Talk:CT scan/Archive 2

Archive 1

Archive 2

Archive 3

Archive 4

sinogram?

an edit was recently made to sinogram (a disambiguation page) such that one of its definitions now points to this article. However, this article does not mention the term. Could someone who is knowledgeable in this area please integrate mention the concept into this article, or change the disambiguation page to point to a more appropriate target? Thanks. Agradman (talk) 18:23, 15 June 2009 (UTC)

added details: Originally, the page only included Radon Transform and Chinese Character (history). Subsequently, someone added tomographic reconstruction (history). Subsequently, someone joined radon transform & tomographic reconstruction with the phrase, "or equivently" (history). This led me to view the concepts as identical, so I brought the page to this version (history). My error was corrected to its current form (history)by Sławomir Biały, an editor who is knowledgeable about the radon transform. Agradman (talk) 18:40, 15 June 2009 (UTC)

This article is fundamentally incorrect

According to this article, a CT scanner is a medical device. This is not true, the medical CT scanner is only one of the many applications of this technology! Will someone please help fix this —Preceding unsigned comment added by 193.191.9.29 (talk) 10:22, 13 November 2009 (UTC)

Richard Gordon

It is interesting to me that the subject of computed tomography completely ignores the author of the first example CT software - that is, Richard Gordon of the radiology department at the University of Manitoba. Indeed, if one reviews the material otherwise available through Gabor Hermann, one learns that Richard Gordon wrote the first version of the software product now known at SNARK. 206.45.135.77 (talk) 01:05, 2 May 2010 (UTC)

Computed tomography versus MRI

Moved this improperly placed link from the article to here for inclusion/discussion:

• guidelines for appropriate use of CT, some discussion of MRI and Ultrasound as alternatives

--Lexein (talk) 18:22, 27 May 2010 (UTC)

Merged Synchrotron X-ray content

In Jan 2008 User:Radagast83 merged content from article Synchrotron X-ray tomographic microscopy I had started. A previous merge was proposed in Aug 2007, but was voted down.

• Why was it merged?
• Where did this content go? It appears it was simply removed.
• Should Synchrotron X-ray tomographic microscopy be recreated?

- RoyBoy 15:06, 6 June 2010 (UTC)

Windowing

I wonder what the most commonly used bit-rate for the storage matrix is in current medical CT systems. If a range of 4000 HU is used to describe practically the whole spectrum of tissue in the human body, a 12-bit matrix would allow 4096 distinct values to be stored. A 8-bit window would allow 256 grey values to be used for 100 Houndsfield units. This gives a resolution of 2,5 grey values for 1 HU. This seems nice, but in face the input and storage in the processing matrix is only 12 bit and gives a resolution of 1 value per 1 HU. Therefore, those 2,5 grey values are all and the same. Nowadays physicians still look at CT's to diagnose patients, but more and more computers and their filters are used to guide the physician through the scan and look for trouble before the physician does. For this reason a higher storage matrix bit rate of 16 bits would increase the resolution (in theory) 65 fold and windows can be smaller to distinguish between even more detail (in contrast). - Remi Verhoeven, Eindhoven University of Technology (talk) 10:05, 13 August 2010 (UTC)

A span of 4000 Hounsfield units is actually very reasonable for CT data, and little would be gained by either increasing the dynamic range, or by introducing fractional units. In practice, typical windows are 400 HU wide - mapping 400 HU onto 256 grey levels (or 1 grey-level onto 1.6 HU). Further, image noise is sufficiently high that even a precision of 1 HU is unnecessary - as the noise in a typical CT image has a standard deviation of approximatley 5-10 HU, and considerably more for studies where radiation exposure needs to be minimized.

The typical data format for CT data is 16 bpp of which 12 bpp are used to represent -1024 to 3071 HU. ChumpusRex (talk) 20:30, 15 August 2010 (UTC)

The table "Typical scan doses" is Wrong for U.S. CT Scans

The table under "Typical scan doses" has radiation exposure values markedly less than the commonly given figures. For instance, a chest, abdomen and pelvis CT is listed at 9.9 mSv but numerous sources have 18 mSv. This latter figure is from Mettler FA, et al: Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog, Radiology 2008 248:254-263). Mettler's values are for the U.S. and not the U.K. which the table cites. However, since the U.S. does more CT scans than any other country, I think we should be using U.S. figures. — Preceding unsigned comment added by TL36 (talk • contribs) 07:05, 30 December 2010 (UTC)

Link Rot fix

Is this a good replacement for the WP:dead link on cite note number 7?--Breawycker (talk to me!) Review Me! 22:03, 27 March 2011 (UTC)

Er, is what a good replacement for etc. etc.? --Redrose64 (talk) 14:09, 28 March 2011 (UTC)

this would be a good replacement.Breawycker (talk to me!) Review Me! 02:14, 1 April 2011 (UTC)

No, because it returns: "Page not found The page you are looking for was not available. This may be because the page was moved or deleted, or because the address in the address bar is incorrect. Please try one of the following: * If you have typed the web address into the address bar yourself, make sure that it is spelled correctly. * Go to the Health Protection Agency home page and use the links available to navigate to the information you are looking for. * Alternatively, use the website search facility available on the home page to find the information you are looking for.". --Redrose64 (talk) 11:52, 1 April 2011 (UTC)

Cancer estimates

The sentence in the intro that reads, "It is estimated that 0.4% of current cancers in the United States are due to CTs performed in the past..." egregiously misrepresents the source article. From the NEJM article that was cited:

"On the basis of such risk estimates and data on CT use from 1991 through 1996, it has been estimated that about 0.4% of all cancers in the United States may be attributable to the radiation from CT studies."

'may be attributable to' =/= 'due to'. Might sound nit-picky, but to say that cases of cancer are due to CT scans suggests an extremely strong causal link, i.e. that in many cases patients who would not otherwise have developed cancer got cancer directly as a result of having a CT scan. The original statement is not that strong, and suggests a statistically significant increased incidence of cancer in patients who receive CT scans. In addition, 'may be attributable' suggests that in the relevant cancer cases, the CT scan may have contributed to the patient developing cancer, not that it caused it independently of any other conditions.

Instead of paraphrasing the statement in a misleading manner, it makes more sense to just quote the article directly. Vikingurinn (talk) 20:14, 11 December 2011 (UTC)

Typically we paraphrase rather than quote, we also typically use more plane language.--Doc James (talk · contribs · email) 04:58, 13 December 2011 (UTC)

Adverse effects

I've done a search for review articles from 2007 to the present, and found:

• Baker JE, Moulder JE, Hopewell JW (2011). "Radiation as a risk factor for cardiovascular disease". Antioxid. Redox Signal. 15 (7): 1945–56. doi:10.1089/ars.2010.3742. PMC 3159113. PMID 21091078. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Pauwels EK, Bourguignon M (2011). "Cancer induction caused by radiation due to computed tomography: a critical note". Acta Radiol. 52 (7): 767–73. doi:10.1258/ar.2011.100496. PMID 21742785. {{cite journal}}: Unknown parameter |month= ignored (help)

• Schonfeld SJ, Lee C, Berrington de González A (2011). "Medical exposure to radiation and thyroid cancer". Clin Oncol (R Coll Radiol). 23 (4): 244–50. doi:10.1016/j.clon.2011.01.159. PMID 21296564. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Lin EC (2010). "Radiation risk from medical imaging". Mayo Clin. Proc. 85 (12): 1142–6, quiz 1146. doi:10.4065/mcp.2010.0260. PMC 2996147. PMID 21123642. {{cite journal}}: Unknown parameter |month= ignored (help)

• Roobottom CA, Mitchell G, Morgan-Hughes G (2010). "Radiation-reduction strategies in cardiac computed tomographic angiography". Clin Radiol. 65 (11): 859–67. doi:10.1016/j.crad.2010.04.021. PMID 20933639. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Kelly RM, Doyle P, Bennett J, McKavanagh P, Donnelly P, Ball PA (2011). "Re.: Radiation-reduction strategies in cardiac computed tomographic angiography". Clin Radiol. 66 (5): 485–6. doi:10.1016/j.crad.2010.12.007. PMID 21315323. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Scaife ER, Rollins MD (2010). "Managing radiation risk in the evaluation of the pediatric trauma patient". Semin. Pediatr. Surg. 19 (4): 252–6. doi:10.1053/j.sempedsurg.2010.06.004. PMID 20889080. {{cite journal}}: Unknown parameter |month= ignored (help)

• Hendrick RE (2010). "Radiation doses and cancer risks from breast imaging studies". Radiology. 257 (1): 246–53. doi:10.1148/radiol.10100570. PMID 20736332. {{cite journal}}: Unknown parameter |month= ignored (help)

• Goske MJ, Applegate KE, Bell C; et al. (2010). "Image Gently: providing practical educational tools and advocacy to accelerate radiation protection for children worldwide". Semin. Ultrasound CT MR. 31 (1): 57–63. doi:10.1053/j.sult.2009.09.007. PMID 20102697. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Romano S, Romano L (2010). "Utilization patterns of multidetector computed tomography in elective and emergency conditions: indications, exposure risk, and diagnostic gain". Semin. Ultrasound CT MR. 31 (1): 53–6. doi:10.1053/j.sult.2009.10.002. PMID 20102696. {{cite journal}}: Unknown parameter |month= ignored (help)

• Birnbaum S (2010). "Radiation protection in the era of helical CT: practical patient based programs for decreasing patient exposure". Semin. Ultrasound CT MR. 31 (1): 46–52. doi:10.1053/j.sult.2009.09.006. PMID 20102695. {{cite journal}}: Unknown parameter |month= ignored (help)

• Tsapaki V, Rehani M, Saini S (2010). "Radiation safety in abdominal computed tomography". Semin. Ultrasound CT MR. 31 (1): 29–38. doi:10.1053/j.sult.2009.09.004. PMID 20102693. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Huppmann MV, Johnson WB, Javitt MC (2010). "Radiation risks from exposure to chest computed tomography". Semin. Ultrasound CT MR. 31 (1): 14–28. doi:10.1053/j.sult.2009.09.003. PMID 20102692. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Shetty MK (2010). "Abdominal computed tomography during pregnancy: a review of indications and fetal radiation exposure issues". Semin. Ultrasound CT MR. 31 (1): 3–7. doi:10.1053/j.sult.2009.09.001. PMID 20102690. {{cite journal}}: Unknown parameter |month= ignored (help)

• Devine CE, Mawlawi O (2010). "Radiation safety with positron emission tomography and computed tomography". Semin. Ultrasound CT MR. 31 (1): 39–45. doi:10.1053/j.sult.2009.09.005. PMID 20102694. {{cite journal}}: Unknown parameter |month= ignored (help)

• Gunn ML, Kohr JR (2010). "State of the art: technologies for computed tomography dose reduction". Emerg Radiol. 17 (3): 209–18. doi:10.1007/s10140-009-0850-6. PMID 19936808. {{cite journal}}: Unknown parameter |month= ignored (help)

• Street M, Brady Z, Van Every B, Thomson KR (2009). "Radiation exposure and the justification of computed tomography scanning in an Australian hospital emergency department". Intern Med J. 39 (11): 713–9. doi:10.1111/j.1445-5994.2009.01956.x. PMID 19323702. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

• Mayo JR (2008). "Radiation dose issues in longitudinal studies involving computed tomography". Proc Am Thorac Soc. 5 (9): 934–9. doi:10.1513/pats.200808-079QC. PMID 19056720. {{cite journal}}: Unknown parameter |month= ignored (help)

• Brenner DJ, Hall EJ (2007). "Computed tomography--an increasing source of radiation exposure". N. Engl. J. Med. 357 (22): 2277–84. doi:10.1056/NEJMra072149. PMID 18046031. {{cite journal}}: Unknown parameter |month= ignored (help)

I haven't looked at them yet, but I hope they'll provide a picture of the current state of the science on risk and CT. I'll get back to this later. --Anthonyhcole (talk) 09:12, 28 April 2012 (UTC)

"Effective dose estimates are best used to assess the general level of radiation risk and not to determine the exact radiation dose from an imaging study. Effective dose estimates for individual patients are subject to a substantial level of uncertainty." FROM http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996147/?tool=pmcentrez — Preceding unsigned comment added by 79.177.205.166 (talk) 17:01, 28 April 2012 (UTC) "The effective dose is not measured but is a theoretical calculated dose based on the organs exposed by the applied radiation multiplied by tissue-weighting factors. Because the tissue-weighting factors can change with new data and continuing analysis of existing data, the effective dose estimates can change over time." FROM http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996147/?tool=pmcentrez — Preceding unsigned comment added by 79.177.205.166 (talk) 17:06, 28 April 2012 (UTC)

I haven't read yet all the linked articles, but please pay attention that the cited source of the risk estimates, is usually the study of the Japanese survivors of the nuclear attack. This teach us that the scientific community lack theoretical capacity of estimation of the consequences of the molecular damage to the DNA, and thus attempt to estimate consequences that are easy to diagnose, i.e. cancer, statistically from that event. However radiation damage from a nuclear explosion may be different (lower or higher) than from pure x-ray, Japanese may have different (more/less) susceptibility to cancer (or other health conditions), and conditions that are difficult to diagnose were ignored.

The fact that radiation is certain to cause the molecular damage to the DNA was demonstrated in many experiments, and it is a matter that is related to physics/chemistry rather than medicine.

After the damage is caused, the process of repair of the damage was demonstrated experimentally to have certain odds of faults, due to which some faults remain. Conversely, the studies that showed reduced IQ, and more diseases, in people that were exposed to radiation, indicate that the function of the irradiated cells was altered, and that indicate that DNA alterations remained.

The diseases due to radiation are not limited to cancer: "The indices of morbidity of liquidators for endocrine system diseases exceed by 18.4 times the control ones, for psychical disorders - 9.6 times, for blood circulation diseases - 4.3 times, and all classes of diseases - 1.5 times." FROM http://www.rri.kyoto-u.ac.jp/NSRG/reports/kr21/kr21pdf/Burlakova.pdf , there is also the Swedish study of IQ at adulthood of irradiated infants, and also studies that showed that the IQ of children that were irradiated for cancer were reduced significantly and in a gradual way in a manner over time, each year the IQ was lower than the previous year, and children that started with above average IQ ended up with below average IQ: "The estimated decline in FSIQ after 4 years was 17.4 points." http://jco.ascopubs.org/content/19/15/3470.full http://jco.ascopubs.org/content/19/15/3470/F4.expansion.html — Preceding unsigned comment added by 79.177.205.166 (talk) 18:36, 28 April 2012 (UTC)

About this: "CT scans use a high level of ionizing radiation, which may cause DNA double strand breaks at a rate of 35 double strand breaks per Gray,[11]" - something is missing: the rate of "35 double strand breaks per Gray" is per cell. This point was included in the previous version. The number of DSBs is probably the average i.e. a particular cell may have more, or less DSBs. E.g. a chest CT cause 0.45 DSBs/cell which means that in 100 cells, on average, there would be 45 new DSBs due to the irradiation. Also about "which may cause DNA double strand breaks" - "may" is too relaxed - it would be very improbable that no DSB would occur, or that they would occur at a significantly lower rate. 79.177.205.166 (talk) 01:24, 29 April 2012 (UTC)

I apologise for the delay in getting back to you. It will take me some time to absorb all this, and I have a bit on at work. It may take a week or more before I can respond. --Anthonyhcole (talk) 16:37, 30 April 2012 (UTC)

Cancer Risks

Hi, most of the information below has been thoroughly debunked, and I've added 6 citations that illustrate this (and I was being nice... there are tons more to refute this sensationalist nonsense). Can we jsut remove the original citation about cancer risk until the actual study currently underway for CT patients concludes? — Preceding unsigned comment added by 71.197.146.147 (talk) 01:55, 10 June 2011 (UTC)

I haven't added this due to the insufficient access and time to medical journals for references. I'm sure someone else can find this information out for me? "The amount of cancer-causing radiation exposure in CT scans can vary fourfold or more with different machines, even when identical tests are performed" "Experts have estimated that while the risk of a patient getting a fatal cancer from a chest X-ray is one in 625,000, it is one in 1600 for a chest CT scan and one in 1100 for a pelvic or abdominal CT." referenced from http://www.theaustralian.com.au/news/alarm-grows-over-high-ct-radiation/story-e6frg6no-1225759204933 MrAnderson7 (talk) 00:51, 17 December 2009 (UTC)

• Yes, this information was covered in the US as well..the Today Show, I think?... I googled it and here is a link:

http://www.usatoday.com/news/health/2009-12-15-radiation15_st_N.htm Gandydancer (talk) 02:14, 17 December 2009 (UTC)

The article cites a 23% risk of dying from cancer. Perhaps this is true in some countries, but the worldwide risk is 12.5% as determined by the WHO in 2002, and cited in Wikipedia's article, List of causes of death by rate: http://www.who.int/whr/2004/annex/topic/en/annex_2_en.pdf 98.154.77.115 (talk) 22:19, 13 May 2010 (UTC)

Some peer-review articles and some pop-ed articles (including the previously mentioned USA-Today article) properly mention that that CT scans are (slightly?) more risky for people with rapidly dividing cells. Who would this include? "All young people" and "anyone with cancer in the location to be scanned". Now I guess it goes without saying that a CT scan is preferable to exploratory surgery; so if you are willing to have corrective surgery then a CT scan is probably desired. If you will not authorize surgery, and are worried about the risks of a CT scan, then perhaps a CT scan should be avoided. Just my two cents worth. Neilrieck (talk) 10:48, 14 May 2012 (UTC)

A new primary research article in the Lancet

[1] Doc James (talk · contribs · email) 18:54, 7 June 2012 (UTC)

IP adding unsupported content

We have an IP adding a great deal of unsupported content and content that does not pertain to CT.

Studies showed that radiation of ionizing radiation caused cognitive problems. Radiation of 60-310 mGy at the 8 to 15 weeks of gestation, or of 280-870 mGy at the 16 to 25 weeks of gestation caused mental retardation. Radiation of 100 mGy to the head at infancy caused cognitive deficits. Radiation of 1300-1500mGy to the head at childhood caused schizophrenia, and lowered IQ scores. Exposure of adults to 150−500 mSv caused cerebrovascular pathology, and exposure to 300 mSv caused neuropsychiatric, neurophysiological, neuroimmune, neuropsychological, and neuroimaging dose related effects.

This ref does not even mention CT in it [2].

All of the refs supporting this text are primary research papers

CT scans use a high level of ionizing radiation. Ionizing radiation has the capacity to break molecular bonds, and thus alter the molecular structure of the irradiated molecules. In the human body, a cell's operation is controlled by the chemical structure of the DNA molecule included in the cell. Experiments showed that ionizing radiation cause DNA double strand breaks at a rate of 35 double strand breaks per cell per Gray, and removes a portion of the epigenetic markers of the DNA, which regulate the gene expression. At the radiation doses, which typical CT scans impose, a DNA molecule of 40%-100% of the irradiated cells is damaged by one or more double strand breaks. This insult is followed by an effort of the cell in attempt to repair the damaged and broken DNA, however, the repair process is not perfect, and faults that are not properly repaired can cause the cell to stray from its original design of operation. The improper operation can manifest in cell death, cancer, and in other puzzling health conditions, as can be expected from an operation, which randomly alter cell's DNA, and epigenetic markers. A portion of the population possess a flawed DNA repair mechanism, and thus suffer a greater insult due to exposure to radiation. Unlike CT, MRI does not use ionizing radiation, and does not cause double strand breaks to the DNA.A Study found, that the contrast agent increased the radiation damage to the DNA that was caused by CT examination: The presence of iodinated contrast agent during CT increased the double strand breaks levels in peripheral lymphocytes by approximately 30%.

The refs supporting this also do not refer to CT contrast.

The amount of iodine that is administered with the contrast agent is way above the Tolerable Upper Intake Level (UL) for adults, which is 1,100 μg/day (1.1 mg/day), and thus side effects of excess iodine intake may occur. The tolerable upper limit was assessed by analyzing the effect of supplementation on thyroid-stimulating hormone. "Iodine supplementation over this limit has been shown to potentially contribute to an underlying thyroid pathology in those with Hashimoto’s thyroiditis, Graves’ disease, or exacerbation of nodularities in euthyroid individuals if intake exceeds 20 mg iodine or iodide. Population studies have shown excessive iodine intake may increase the prevalence of autoimmune thyroiditis in animals and humans, increasing the risk of overt hypothyroidism."

Doc James (talk · contribs · email) 21:23, 9 June 2012 (UTC)

Agreed, sources that do not explicitly mention CT do not belong here, per WP:SYNTH. Yobol (talk) 21:29, 9 June 2012 (UTC)

Response of 79.179.224.214 (talk) 22:43, 9 June 2012 (UTC) to First section: CT use high energy x-ray ionizing radiation, that cause the body to absorb a large dose of ionizing radiation. At the UK study page 96, during routine head, up to 140 mGy were absorbed. Now, this procedure would be performed twice, once with and once without iodine, thus multiplying the amount of radiation by two. Thus 280 up mGy would be absorbed. This page is from a hospital stating "Our shuttle mode CTP scanning protocol described above results in a radiation exposure, the volumetric CT dose index (CTDIvol), of 349 mGy.". The FDA allow radiation of up to 500 mGy, a limit that was imposed due to adverse effects, that did occur when CT machines output radiation exceeded that. In this document hosted on US governmental public health web site, it is stated on page 12, that at Ceder Sinai hospital, 269 patients each absorbed 4286mGy of ionizing radiation, more than twice of what radiation therapy patients absorb in a fractionated radiation therapy session. These patients experienced adverse effects of radiation therapy as can be seen at page 13, showing images of their hair loss. (Could someone upload these pictures?)

Now, given the fact, which I assume is not under dispute, that CT machines commonly subject patients to hundreds of mGys, and sometimes to thousands of mGys of ionizing radiation, it is important to described the studied adverse effects of ionizing radiation. This is not original research. CT inflict ionizing radiation on patients, and ionizing radiation cause adverse effects.

Response to Second section: You complain about use of primary research papers in the second section, however, I have reviewed the rules of Wikipedia, and found no rule forbidding use of primary research papers.

Response to Third section: I will think about it, and respond later.

Note, someone have deleted the section about kidney problems due to contrast media. That contribution was not mine, and I don't know where are the refs required for it. Why did that someone just delete stuff without asking for the refs, like by marking next to the wanted refs? 79.179.224.214 (talk) 22:43, 9 June 2012 (UTC)

79.179.224.214 (talk) 22:52, 9 June 2012 (UTC): I think that "Contrast" is not an adverse reaction. Death is, allergy is, etc. DNA damage is also an adverse reaction, but eating fried food cause DNA damage, being in the sun cause DNA damage, but not to the extent that the CT does. Thus the title should be extensive DNA damage, and not just DNA damage. 79.179.224.214 (talk) 22:52, 9 June 2012 (UTC)

You said

Now, given the fact, which I assume is not under dispute, that CT machines commonly subject patients to hundreds of mGys, and sometimes to thousands of mGys of ionizing radiation, it is important to described the studied adverse effects of ionizing radiation.

Everything on Wikipedia is continually under dispute. I think that the way to post this is to provide a source which states the range of radiation to which CT machines expose patients, then state that range and reference a source which says what happens at that range. Also link to a full article on ionizing radiation for sources which are not explicitly about CT scans. When you use a source which does not explicitly mention the article's subject that is WP:SYNTH.

Here is the requested Wikipedia rule which talks about primary sources - WP:PRIMARY. The ideal source is a secondary source which talks about the first paper.

You asked why a section was deleted for not having references when a citation needed tag could have been used. For health articles many editors use the Medical Manual of Style - WP:MEDMOS. This is because it is often easy to see when information is not from a secondary source or when it is contrary to popular understanding. On popular culture articles sometimes Wikipedia rules get relaxed and broken; in health articles editors tend to follow the rule for having verification for all statements per WP:V. Thanks a lot for your interest in this. Blue Rasberry (talk) 23:03, 9 June 2012 (UTC)

Yes we use secondary sources as mentioned by both Blue and Yobol. This [3] is not a secondary source. The key of WP:SYNTH is "Do not combine material from multiple sources to reach or imply a conclusion not explicitly stated by any of the sources". Only a percentage of CTs use contrast and contrast does have some extra risks. Thus it is reasonable to discuss contrast as a section to itself. I in fact added some references to the section on kidney issues. Doc James (talk · contribs · email) 23:09, 9 June 2012 (UTC)

The WP:PRIMARY doesn't state that primary sources can not be used, it just state how they should be used. Instead of helping with the semantics, you (DocJames) just destroy stuff. Why?79.179.224.214 (talk) 00:32, 10 June 2012 (UTC)

Please, I want to help and so many other people do also. If you want other opinions about what you are doing then consider going to the WP:TEAHOUSE, which is a place where new Wikipedia users can ask questions from very friendly people. Also consider registering an account so that you can have sustained conversations. No one wants to destroy work. If you have questions then try to be more specific than asking why things are removed - the answer is that Wikipedia has rules and I think that if you asked other people they would also say that your contributions are not following them. Check out primary and synth again. Blue Rasberry (talk) 02:15, 10 June 2012 (UTC)

References

Dispute filed

User:79.179.224.214 has requested mediation for this issue here - Wikipedia:Dispute_resolution_noticeboard#X-ray_computed_tomography

I feel like that request is premature because discussion is still happening on this talk page. The discussion only began on 9 June. I think that Doc James has a legitimate concern that User:79.179.224.214 wants to use primary sources, and I think that User:79.179.224.214 has not explained why primary sources need to be used in this situation. Blue Rasberry (talk) 15:35, 11 June 2012 (UTC)

I am a volunteer clerk/mediator at the Wikipedia:Dispute resolution noticeboard. There is no requirement for anyone to respond at WP:DRN, but I wanted everyone involved to be notified in case they chose to join the discussion there. In my opinion, in this particular case it is useful to have a discussion at DRN. I have given 79.179.224.214 some advice there that I hope will resolve this issue. --Guy Macon (talk) 17:16, 11 June 2012 (UTC)

How many mGy is a CT?

The FDA mentions much lower levels of radiation from a CT (in the range of 2-8 mGy / mSv). This [4] is a primary source and it appears to be interpreted wrong. Doc James (talk · contribs · email) 23:28, 9 June 2012 (UTC)

79.179.224.214 (talk) 00:05, 10 June 2012 (UTC)

0.001 Gray = mGy is the real physics kind of unit, that measure radiation. It measure how many Joule are absorbed by one Kg of matter. Head CT as you can see in the UK study inflict about 60 mGy on average, but sometime as high as 140 mGy. This means that a Kg of an average head, that is examined, absorbs on average 0.06 Joule of energy. This doesn't seem as much, except that the energy is in a form of ionizing radiation, which make it large enough to cause a double strand break to two DNA molecules in every cell that was irradiated.

On the other hand mSv=0.001 Sievert is a made up unit, that I don't know who has concocted, that on theory work by estimating the real radiation cancer risk, and then stating the real radiation value, that if all the body would have been irradiated, the same risk would have been. Considering that estimation of cancer risks from radiation is still under debate, this unit should be considered under debate as well. Moreover, that unit hide other adverse effect that could occur, such as the extent of DNA damage.

Example, suppose you irradiate the head with 60 mGy, now they estimate the risk of cancer to be "X", and they estimate that irradiating the whole body with 1.5 mGy would also have cancer risk "X", and so they say that the effective dose is 1.5 mSv. Why the big difference? A. because they think that the head is primarily non proliferating cells, and thus have low cancer risk, B. suppose you spread the energy in joules, that the head absorbs with this 60mGy radiation, over the whole body, suppose the head weigh 2Kg this is 0.12 joules, and suppose the whole body weigh 60Kg, then that is 0.12joules/60Kg=0.002=2[joule/Kg]=2mGy; so if you irradiate with 2mGy the whole body, the same amount of ionizing radiation energy, and interactions with the DNA would occur, and thus the same cancer risk. I think this also helps doctors that like to subdue resistance of their patients, as I have seen stated in some article, the article with instructions for the Dr. went something like - state the radiation from the CT as 2mSv, then compare it to the background radiation level of 3mSv per year, which everyone absorbs anyways. But the head still absorbs 60mGy, and this is more like 20 years of background radiation.

79.179.224.214 (talk) 00:05, 10 June 2012 (UTC)

79.179.224.214 (talk) 00:36, 10 June 2012 (UTC) Oh grate. Now I see that even though you don't have a clue between mSv, to mGy, you have edited out all the sections about the doses in mGy. What is the motivation for that. Please do tell. 79.179.224.214 (talk) 00:36, 10 June 2012 (UTC)

79.179.224.214 (talk) 01:31, 10 June 2012 (UTC) Even better, now I see that you have decided that mGy=mSv for X-RAYs, and have put a dead link to prove it. Why do you change stuff you don't understand without consulting? BTW, mGy=mSv for xrays, only if the whole body is irradiated with the same value of radiation, something that doesn't occur often with CTs, even when the whole body is scanned, since the skull has to be bombard with higher radiation in order to get a clear glimps to what is inside bone. 79.179.224.214 (talk) 01:31, 10 June 2012 (UTC)

Fixed the ref for you. Doc James (talk · contribs · email) 01:33, 10 June 2012 (UTC)

79.179.224.214 (talk) 01:47, 10 June 2012 (UTC) The information at that page is wrong. Do you consider it a primary, secondary (or what kind of a source?) that you allow yourself to reference it? Had you read the UK Study, you would have read page 5-8 describing how the effective dose is calculated, which is clearly different than the CTDIvol, and you would have read page 31, in which side by side the for the same CT examination the mSv value is clearly different than the mGy value determined for the same examination. Why do you torment me?79.179.224.214 (talk) 01:53, 10 June 2012 (UTC)

Keep things simple by putting a reference at the end of every sentence. Do not draw conclusions which are not in your references. No one is tormenting you - Wikipedia's guidelines have been around for a long time and they are available for you to read. I really appreciate your interest and what you are trying to do but follow the rules and be WP:NICE. Blue Rasberry (talk) 02:20, 10 June 2012 (UTC)

I am sorry. I am just a bit frustrated, to see many of my contributions just deleted, without discussion, or attempt to rephrase them to fit the semantic requirements. Without a point by point examination. Etc. And to top it all, the one who have deleted my contributions, due to semantic reasons, has added an error backed up by a simple web page, that has an error in it. I think this is in violation of the rules, since it is not even a research, and there is a research that contradict that simple web page. I guess I can try to rephrase the contributions by myself, however, I don't think my contributions got a fair hearing here, and who is to say, that this will not happen again? and if so what is the point? 79.179.224.214 (talk) 02:55, 10 June 2012 (UTC)

The issue with your additions had to do with the references. The references where simply not appropriate.Doc James (talk · contribs · email) 05:28, 10 June 2012 (UTC)

Prove that. With a reference that prove it. And with an exact quote from that recerence. I think, that it is possible that you are wrong with the rules too.79.179.224.214 (talk) 06:15, 10 June 2012 (UTC)

Read WP:MEDRS "Ideal sources for biomedical material include general or systematic reviews in reliable, third-party, published sources, such as reputable medical journals, widely recognised standard textbooks written by experts in a field, or medical guidelines and position statements from nationally or internationally recognised expert bodies." Doc James (talk · contribs · email) 06:55, 10 June 2012 (UTC)

This does not prove it. It just state what is ideal. It does not state that non ideal sources can't be uses.79.179.224.214 (talk) 07:26, 10 June 2012 (UTC)

For important medical information we use ideal sources. Doc James (talk · contribs · email) 07:28, 10 June 2012 (UTC)

Prove that. With a reference that prove it. And with an exact quote from that recerence. I think, that it is possible that you are wrong with the rules too.79.179.224.214 (talk) 07:42, 10 June 2012 (UTC)

"1 mSv is the dose produced by exposure to 1 milligray (mG) of radiation." [5] Another ref is The essential physics of medical imaging (2. ed. ed.). Philadelphia [u.a.]: Lippincott Williams & Wilkins. 2002. p. 57. ISBN 9780683301182. {{cite book}}: |edition= has extra text (help); |first= missing |last= (help)

Yes I do know that number are different for CTDIw (which are in mGy) but the recommended measurement of diagnostic radiation is in mSv not mGy.

Doc James (talk · contribs ·email) 07:15, 10 June 2012 (UTC)

Did you notice that that quote is from a military book? Military in the context of radiation deals with radiation contamination due to radioactive substance, which form a uniform radiation through the whole body. This is not the case in CTs. If you look back you will see, that I have already addressed that issue in this talk page.79.179.224.214 (talk) 07:42, 10 June 2012 (UTC)

Who recommended? Why he/she recommended it? Do you have a primary or a secondary source? Prove it. 79.179.224.214 (talk) 07:58, 10 June 2012 (UTC)

That is why I provided "The essential physics of medical imaging"Doc James (talk · contribs · email) 08:00, 10 June 2012 (UTC)

This doesn't really answer my query. Anyway, what page? 79.179.224.214 (talk) 08:18, 10 June 2012 (UTC)

Per Applin, David (2002). Biology extension file (Rev. ed. ed.). Cheltenham: Nelson Thornes. p. 8. ISBN 9780748762569. {{cite book}}: |edition= has extra text (help) "the effect of ionizing radiation on the human body is measured in mSv" Thus we are not adding mGy.Doc James (talk · contribs · email) 08:39, 10 June 2012 (UTC)

Please provide the page. Without seeing the page, I can tell you that in other sources, in which similar things were written, the effect they talked about was cancer and hereditary effects. Those are the only body effects, that these scientist think that they know to measure, and yet there still is debate over the cancer risks figures, hence they don't really know, yet this unit exist. Do you know how it is computed? You take the mGy value and multiply it with a factor that correspond to the estimated sensitivity of the organ that was radiated. So, there you have it. The gray unit is the real thing. The Sievert is based on estimations, that are under debate. See the publication dates of these factors, they change them every few years as they figure out that the previous ones were off. The same dose in Gray would be one value of Sievert according to one year's factors, and an other on an other year.79.179.224.214 (talk) 08:55, 10 June 2012 (UTC)

I have added page numbers. Doc James (talk · contribs · email) 08:57, 10 June 2012 (UTC)

Thanks, I have managed to read the first one. Anyway, what do you think are the biological effects they talk about? Do you know how the effective dose is computed? Did you notice that many researches include the radiation absorbed dose in Gray, the CTDIvol in Gray? Does it cost you anything to include the absorbed dose in Gray?79.179.224.214 (talk) 09:11, 10 June 2012 (UTC)

I have asked you the above questions in order that you would educate yourself about them. This will help you understand that Sievert is not equal to Gray in the context of CTs. Did you understand that yet? Please read the dosimetry section here and chapter 3 here. This will help you understand that. Please Google search the following line: effective dose cancer hereditary. I didn't read the results, but according to google's short description, I think the 1st,6th, 7th results, would help you understand the answer to the first question. You might want to search in these document for cancer or hereditary.79.179.224.214 (talk) 16:38, 10 June 2012 (UTC)

I am guessing that you prefer books, if so, you can search the same thing in google books here is one result.79.179.224.214 (talk) 17:39, 10 June 2012 (UTC)

I think, that displaying only Sievert radiation dose values violates neutral point of view WP:NPOV. It is not up to anybody here to decide which units are "good". Radiation doses in Gray, and Gray*cm exist in the same source from which the Sievert values were taken. If that source is acceptable for Sievert it should be acceptable for Gray, and Gray*Cm. — Preceding unsigned comment added by 79.182.215.205 (talk) 20:36, 14 June 2012 (UTC)

This article [6] from the New England Journal of Medicine clearly states CT is measured in both absorbed dose in Gray and in estimated equivalent effective dose in sieverts. Additionally FDA notes estimates can vary by factor of 10 so there's clearly justification for including both in the article. [7] Nobody Ent 21:18, 14 June 2012 (UTC)

Working together

I am happy to work together to improve this page if we all use pubmed index review article from the last 5-8 years that directly refer to the effects of CT imaging.Doc James (talk · contribs · email) 07:10, 10 June 2012 (UTC)

Lets start with what we can agree up on, and then get to resolve what we can't. I suggest to start with the Extensive DNA damage section. What is wrong with that section according to you? 79.179.224.214 (talk) 07:51, 10 June 2012 (UTC)

Sure "Extensive DNA damage" is not an adverse effect per say. It is the pathophysiological process that results in cancer. Ie people do not come in complaining of extensive DNA damage. There are some good references for cancer. We do not need to resort to in vitro studies or animal models. It is well accepted that CT imaging causes cancer. Doc James (talk · contribs · email) 07:56, 10 June 2012 (UTC)

From Adverse effect "In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.". Do we agree that DNA damage is harmful/undesired? Cancer is just one form of DNA damage, that is easy to detect, because people die from it, and they have strange lumps all over their bodies when they so die. Other types of DNA damage do occur, and their health effect are described in one of the referenced articles, which found all diseases among people exposed to radiation in chernobyl to rise. There is also the cognitive deficits, hair loss, etc, all are due to DNA damage, and how many issues, or preformance indicators, doctors have problem to diagnose and are not addressed by research due to that? The DNA is the engine of life, therefor damage to it is an adverse effect. Can we agree? 79.179.224.214 (talk) 08:13, 10 June 2012 (UTC)

We should be looking at hard end point rather than surrogate markers, DNA damage is a surrogate marker. Here is an interesting review Pauwels, EK (2011 Sep 1). "Cancer induction caused by radiation due to computed tomography: a critical note". Acta radiologica (Stockholm, Sweden : 1987). 52 (7): 767–73. PMID 21742785. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help) Doc James (talk · contribs · email) 08:22, 10 June 2012 (UTC)

I think that Extensive DNA damage is not a surrogate marker. DNA damage cause the cells to function improperly which is a culprit for other diseases and sub-optimal performance. This is an issue that I think is of interest to most people. But this is a debate of the importance of that adverse effects, which I think is redundant, because I think that the adverse effects section should include all adverse effects. Just like in a medication leaflet there could be adverse effects from a small itch up to an agonizing death.79.179.224.214 (talk) 08:41, 10 June 2012 (UTC)

DNA damage may result in neither signs nor symptoms and thus is not an adverse effect. But let hear what others have to say. Doc James (talk · contribs · email) 08:56, 10 June 2012 (UTC)

When one take a medication, one may experience no side effects, despite the label describing a side effect. Adverse effects are things that can happen as a result of the procedure, not only things that are sure to happen. As it happens to be, the DNA damage is 100% certain to happen. The only question is which part of the DNA would be damaged? would it be fixed correctly? what genetic information would be lost due to homologue recombination? How all of that effect the body function? One of the answers to this is cancer. But other answers also exist. As DNA damage can be harmful and is undesired (do anyone desire DNA damage?) it is an adverse effect 79.179.224.214 (talk) 09:27, 10 June 2012 (UTC)

Btw, can you use similar logic to claim that cancer is not an adverse effect? I.e. something like - 'someone with cancer doesn't feel the cancer, cancer is not an adverse effect. Someone with cancer might feel pain, lack of appetite, these are the adverse reactions.'. If yes, should we replace the cancer title with a list of cancer symptoms? 79.179.224.214 (talk) 09:40, 10 June 2012 (UTC)

Lets continue on the above two topics, and also on more topics: What is wrong by you with the cognitive decline section?79.179.224.214 (talk) 17:10, 10 June 2012 (UTC)

The same thing as with all the content in question. It was not supported by proper references. If you insist on using primary sources there is really nothing more to discuss. Doc James (talk · contribs · email) 22:43, 10 June 2012 (UTC)

This is a return to the above discussion, which ends with that I ask you for a proof that only ideal sources can be used, and you not replying. You must prove your opinion or abandon it. — Preceding unsigned comment added by 79.179.224.214 (talk) 23:06, 10 June 2012 (UTC)

Hi 79.179.224.214. First off, have you considered creating creating an account? There are a number of benefits to doing so and it makes communication/referring to one another much easier.

I'm sure that James has linked you to WP:MEDRS. Take a look at section 2, "Basic advice", with emphasis on subsections 2.4–2.6. Does that page explain well why James is asking that review articles be used over an original research piece? It's because hundreds to thousands of papers involving CT scans are published every year, and for a tertiary source like Wikipedia, we are best off using sources that have already attempted to survey and appropriately weight the relevant literature. NW (Talk) 04:20, 11 June 2012 (UTC)

Hi NW. I have reviewed sections 2.4–2.6 of the WP:MEDRS, and I do not see there any statement that primary sources should never be used. On the other hand, I see a lot of statements that primary sources can be used, and describe how primary sources should be used.

E.g. 2.4 "Where In vitro and animal-model data are cited on Wikipedia, it should be clear to the reader that the data are pre-clinical, and the article text should avoid stating or implying that the reported findings necessarily hold true in humans. The level of support for a hypothesis should be evident to the reader.","Results of studies cited or mentioned in Wikipedia should be put in sufficient context that readers can determine their reliability."

2.5 "These instructions are appropriate for actively researched areas with many primary sources and several reviews and may need to be relaxed in areas where little progress is being made or few reviews are being published."

2.6 "Whenever writing about medical claims not supported by mainstream research, it is vital that third-party, independent sources be used. Sources written and reviewed by the advocates of such marginal ideas can be used to describe personal opinions".

For medications, an adverse effects report usually rely on patients' description of their feelings. Here we have scientific researches, that found the adverse effects by means of scientific measurements, and not only by asking patients how they feel. This is a whole order of magnitude grater evidence, and a more objective evidence, than what is commonly accepted for reports of adverse effects. If subjective feeling reports are accepted for reports of adverse effects, then scientific measurements must be accepted as well.

I think that it is important, that people will have all the information with regard to adverse effects, when they are offered a medical procedure. Hiding such information is lying by omission. It is not ethical.

The deletions that Mr. DocJames has performed were not properly explained, and therefor it is impossible to understand the justification. He didn't define the researches that were used, one by one, as primary, secondary, etc. He didn't quote each contribution point, and described which point of the WP:MEDRS it violates. Am I expected to accept DocJames' decisions just because he said so? I think not. I think that if a deletion have merit, then that merit should be explained and proven in detail. 79.179.224.214 (talk) 14:43, 11 June 2012 (UTC)

Isn't this article a secondary review? (see e.g. page 25 that include a table, that concentrate many other researches that were reviewed.)

You stated that you think, that I have "not explained why primary sources need to be used in this situation". Does this mean that you think that in some cases primary sources can be used? 79.179.224.214 (talk) 17:23, 11 June 2012 (UTC) I found this article stating "Radiation induces thousands of single-strand breaks per Gray, but only about 50 double-strand breaks." Is this a secondary source?79.179.224.214 (talk) 18:41, 11 June 2012 (UTC) How about "20–40 DSB foci per nucleus per Gray of radiation for a mammalian cell" ? How about "For X-rays, on average 20–30 DSBs are induced per Gray"?79.179.224.214 (talk) 18:49, 11 June 2012 (UTC) In this case, I don't understand why would anyone prefer to quote a secondary review, in which it is difficult to find how the given fact was determined, over a primary source in which it is clear. An other point, is that Xray creation of DSBs in DNA is a subject of physics not medicine. Thus WP:MEDRS should not apply. 79.179.224.214 (talk) 19:15, 11 June 2012 (UTC)

Few things regarding this article 1) is it pubmed indexed, I am unable to find it on pubmed 2) not once does it mention CT scans thus not sure how it is applicable to this article (this article is about Chernobyl) 3) the radiation doses (>0.3 S or 300 mSv) are many times greater than that from CT imaging. Doc James (talk · contribs · email) 08:06, 12 June 2012 (UTC)

Regarding the dose - the article describe 10mSv to the fetus (which is a whole body exposure to the fetus, and thus equal 10mGy to the abdomen of the mother), 0.1 Gy= 100 mGy to the head of a child, and 0.15 Sv=150 mSv whole body exposure of adult (from a uniform external source, which means that each part of the body including the head absorbed 150mGy). These doses are within the expected doses of contemporary CT scanners.

Regarding the applicability to CT - The article describe the effect on cognitive performance of many sources of radiation, including xray radiation therapy. One of the primary sources referred to in that article state:

"External radiotherapy to the head of infants with dose levels that overlap those from computed tomography may adversely affect intellectual development."

"Irradiation of the brain with dose levels overlapping those imparted by computed tomography can, in at least some instances, adversely affect intellectual development. Although formal diagnostic protocols do not advocate computed tomography in cases of minor head injuries, clinical practice dictated by legal and financial considerations does not always adhere to these protocols. The risk and benefits of computed tomography scans in minor head trauma need re-evaluating.".

Clearly, if radiation from radiotherapy was not effectively the same as from CT, that primary source wouldn't have advised to reevaluate the risks and benefits from CT.

Moreover, the secondary article's review of many cases, that affected human being's cognitive performance, due to radiation from various sources, and during various procedures. It is clear from that, that the ionizing radiation has the effect on the cognitive performance regardless of its source, be it radiation therapy, a yellow CT machine, or a purple one.

Please ignore the following, since it is a common sense remark, and AFIK common sense remarks doesn't count according to Wikipedia rules, but ionizing radiation break molecular bonds, and molecular composition is what affect the performance of the cells. As long as the same molecular changes occur, the same effects will result. Thus it doesn't matter much where the Xrays came from. 79.181.241.242 (talk) 17:15, 12 June 2012 (UTC)

A paragraph from "Computed Tomography — An Increasing Source of Radiation Exposure", that support my view with regard to "Biologic Effects of Low Doses of Ionizing; Radiation Mechanism of Biologic Damage;Ionizing radiation, such as x-rays, is uniquely energetic enough to overcome the binding energy of the electrons orbiting atoms and molecules; thus, these radiations can knock electrons out of their orbits, thereby creating ions. In biologic material exposed to x-rays, the most common scenario is the creation of hydroxyl radicals from x-ray interactions with water molecules; these radicals in turn interact with nearby DNA to cause strand breaks or base damage. X-rays can also ionize DNA directly. Most radiation-induced damage is rapidly repaired by various systems within the cell, but DNA double-strand breaks are less easily repaired, and occasional misrepair can lead to induction of point mutations, chromosomal translocations, and gene fusions, all of which are linked to the induction of cancer.23"

Thus the source of the ionizing radiation is irrelevant for its biological effect.

This paragraph also support the DNA damage section that was removed.

And this article is a secondary source about CT.79.181.241.242 (talk) 20:36, 12 June 2012 (UTC)

Complaints from a reader

One of our readers wrote me through Wikipedia complaining about the state of this page. Thus why I am involved. There is tons of excellent secondary sources which discuss the risk / benefits of CT imaging with due weight. Using primary sources or sources that do not pertain to CT imaging specifically is not needed in this case. And we do not use primary sources typically to refute secondary ones. Doc James (talk · contribs · email) 08:12, 12 June 2012 (UTC)

I am a volunteer clerk/mediator at the Wikipedia:Dispute resolution noticeboard. I am working on what may be a related issue here. As you can see, this has involved telling a particular editor that he cannot use primary sources the way he wants on this page. Meanwhile, the page has been put under full protection for a week. Is there anything else that we at WP:DRN can do to help with this problem? --Guy Macon (talk) 09:00, 12 June 2012 (UTC)

Appreciate your efforts. One of the keys I find to editing Wikipedia is that editors should start by finding the best available evidence and than summarizing it, rather than starting with preconceived ideas and looking for evidence to support those ideas.Doc James (talk · contribs · email) 11:47, 12 June 2012 (UTC)

It's not clear to me what you mean by that remark. Expertise in a field is a valuable, often lacking, resource on Wikipedia that we should encourage rather than discourage. The difficultly is, of course, our editing standards are significantly different than other venues; it can be a difficult and frustrating experience for the both the established Wikipedian and new expert editor to break through cultural differences and find common ground. Nobody Ent 21:22, 14 June 2012 (UTC)

What I mean is that it appears some editors come with personal conclusions and than try to find evidence to support them rather than coming with an open mind and simply summarizing the best available literature.Doc James (talk · contribs · email) 21:29, 14 June 2012 (UTC)

Doc James, some times people attribute their own faults to others. I think, that it would be in your best interest to reevaluate your position in this.

79.182.215.205 (talk) 22:06, 14 June 2012 (UTC)

I would encourage the IP to heed Doc James' advice here. Experts can be especially important because they often know where the best sources to use are. Experts, however, are not allowed to substitute their judgements about a topic or to WP:UNDUEly weight certain aspects of a topic against what is dictated by our sources. Yobol (talk) 22:13, 14 June 2012 (UTC)

Yobol, quoting rules without explaining how they apply in the specific situation is a very good way to say something, without saying anything at all.

79.182.215.205 (talk) 23:08, 14 June 2012 (UTC)

What part of "It appears some editors come with personal conclusions and than try to find evidence to support them rather than coming with an open mind and simply summarizing the best available literature." is quoting a rule without explaining how it applies? The advice is good. Your continued hostility towards Doc James is toxic. He wants what is best for the article too. --Guy Macon (talk) 23:25, 14 June 2012 (UTC)

That comment was a reply to Yobol, including his/her reference to WP:UNDUE, however, since you bring it up, it could apply to Doc James as well. See the discussion in the above sections.

79.182.215.205 (talk) 23:42, 14 June 2012 (UTC)

In far less time than it took to read through the WQA and the DRN and this talk page I found two secondary sources [8], [9] that support much of what the new editor is saying. It's ridiculous to dismiss obvious expert knowledge because a new editor hasn't learned all of the WP-this and WP-that. See WP:IAR. And WP:BITE, of course. Nobody Ent 01:39, 15 June 2012 (UTC)

Both those sources are already used in this article, and neither appear to address disputed content such as cognitive defects and schizophrenia or address the inappropriate use of primary sources or synthesis. Indeed, I'm not sure what disputed content you think is supported by the references you presented; no one disputes there are risks from CT, just that we need to present them appropriately. Yobol (talk) 02:43, 15 June 2012 (UTC)

I was the one who added both those sources :-) and there are many more great ones. Agree completely that their are risk from CT.

Here is another good source Linet, MS (2012 Feb 3). "Cancer risks associated with external radiation from diagnostic imaging procedures". CA: a cancer journal for clinicians. PMID 22307864. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help) Doc James (talk · contribs · email) 03:36, 15 June 2012 (UTC)

Typical scan dose

The "Typical scan dose" section included the following table:

Examination	Typical effective dose (mSv)	(millirem)	Real dose (mGy)	Dose in number of years it would take the irradiated body part to absorb the same energy from background radiation	Dose in number of DNA double strand breaks that are induced per cell
X-ray Personnel security screening scan	0.00025	0.025
Chest X-ray	0.1	10
Head CT	1.5	150	64	21	2.24
Screening mammography	3	300
Abdomen CT	5.3	530	14	4.6	0.49
Chest CT	5.8	580	13	4.3	0.45
CT colonography (virtual colonoscopy)	3.6–8.8	360–880
Chest, abdomen and pelvis CT	9.9	990	12	4	0.42
Cardiac CT angiogram	6.7-13	670–1300
Barium enema	15	1500
Neonatal abdominal CT	20	2000

The following columns were deleted: "real dose (mGy)","Dose in number of years it would take the irradiated body part to absorb the same energy from background radiation", and "Dose in number of DNA double strand breaks that are induced per cell".

The edit summary for that removal stated: "removed wrong stuff".

Later edit rewrote the column title "Typical effective dose (mSv)" with the title "Typical effective dose (mSv = mGy for X-rays)"

The edit summary for that rewrite stated "fixed".

The inserted edit title include the error mSv = mGy for X-rays. That error is supported by a web page at the FDA web site. (BTW, what kind of source is that web page anyway?). However the error is contradicted by many other sources. This include the "Doses from Computed Tomography (CT) examinations in the UK - 2003 Review", which in page 31 include a table with a CTDIvol(mGy) column value of 57mGy for head CT scan, and an E(mSv) column value of 1.5mSv for the same head CT scan. Clearly 1.5mSv is not equal to 1.5mGy in this case, but to 57mGy. That is a big difference. The same source page 9 describe the formula for calculating the effective dose E as E=Edlp,reagion,age*DLP and of DLP as DLP=CTDIvol*L. Hence E=Edlp,reagion,age*L*CTDIvol=something*CTDIvol. CTDIvol is measured in mGy, E is measured in mSv. How can the mSv value be equal to the mGy value, if the mSv value is a multiplication of something with the mGy value? Clearly mSv is not equal to mGy. If you like, there are reference books having the same information, some of which are linked in above discussion sections. Thus there was nothing wrong with the mGy columns, and there is something wrong with the current effective dose column.

The "Dose in number of years it would take the irradiated body part to absorb the same energy from background radiation" column, is a division of the mGy value, by 3mGy which is the background radiation per year. This is a simple calculation, and is allowed.

The "Dose in number of DNA double strand breaks that are induced per cell" column, is a division of the mGy value with the value of 35 DSB per cell per Gray. This is a simple calculation, and is allowed.

I think that the table should be restored to its previous state. If anything should have been removed from it, it is the (millirem) column that doesn't convey any new information compared to the mSv column.

Still waiting on proper sources. Doc James (talk · contribs · email) 20:26, 15 June 2012 (UTC)

Please explain to me why this source is not appropriate. In my view it is a review article for the way doses are computed, and a primary source with regard to measured doses in CTs in the UK. Part of the dose data from it is already quoted in the table. If it is good for what quoted, why is it not good for what wasn't quoted.

79.182.215.205 (talk) 21:04, 15 June 2012 (UTC)

"Cancer risks from diagnostic radiology" , "Adult patient radiation doses from non-cardiac CT examinations: a review of published results."

79.182.215.205 (talk) 03:28, 16 June 2012 (UTC)

With respect to this article: Rothkamm, K (2003 Apr 29). "Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses". Proceedings of the National Academy of Sciences of the United States of America. 100 (9): 5057–62. PMID 12679524. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

1) not listed as a review by pubmed

2) does not once mention CT scans

With respect to this article Hunold, P (2003 Jan). "Radiation exposure during cardiac CT: effective doses at multi-detector row CT and electron-beam CT". Radiology. 226 (1): 145–52. PMID 12511683. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

1) it is a primary source

Other problems include that their is no ref for "Dose in number of years it would take the irradiated body part to absorb the same energy from background radiation" Also this is not a side effect. And no one quotes CTs in number of DNA strands broken.Doc James (talk · contribs · email) 04:32, 16 June 2012 (UTC)

OK ... what does that second source (pmid=12511683) you put here has to do with anything I wrote?

You are correct, "Dose in number of years it would take the irradiated body part to absorb the same energy from background radiation" is not a side effect. I didn't write that as a side effect. Is there a reason in the text for this confusion?

You are correct, it has no ref written next to it ... but I can write for it the ref of the mGy column since it is calculated from its values.

You wrote "And no one quotes CTs in number of DNA strands broken" - People will find this dose much more relevant than any of the others. After all what people care about? They care about the impact over their own structure.

About the first source, I agree that it is primary, and does not mention CT. However, it is used for the '35 DSB per cell per gray' fact, and it mention use of radiation of 90 kV xray, which is the same radiation, that is used in CTs, and hence have the same effect that CT radiation have.

79.182.215.205 (talk) 05:27, 16 June 2012 (UTC)

The current table does not appear to be supported fully by the citations. For example, the "Typical Equivalent Dose" of head CT is described at 64 mSv, but cannot find it anywhere in cited source. I see this in multiple numbers, and I think reverting to the previous version of the table is appropriate until we can verify ALL material. Yobol (talk) 21:44, 17 June 2012 (UTC)

The table which you have reverted to include the statement "mSv = mGy for X-rays". That statement is true for equivalent dose, see the wikipedia article on equivalent dose.

The source "Doses from Computed Tomography (CT) examinations in the UK - 2003 Review", include the value 64mGy for the absorbed dose of a head CT scan.

Thus, according to your own edit "mSv = mGy for X-rays" and the source 64mGy, a head CT scan impart an equivalent dose of 64mSv.

Thus, I am reverting to the previous version. — Preceding unsigned comment added by 79.182.215.205 (talk) 23:01, 17 June 2012 (UTC)

So the numbers are NOT in the source you are using to cite it. You really need to stop. Yobol (talk) 23:04, 17 June 2012 (UTC)

The mGy values are in the source, and they are equal to the mSv values of equivalent dose. I have inserted that column in order to show you how confused the units are. Confusing enough to confuse you, evidently, as you can see your edit is completely wrong - stating mSv=mGy for effective dose, when it is true only for equivalent dose. Moreover no sources needed for calculations, especially when the calculation is a simple equality between absorbed dose and equivalent dose for x-rays.

Thus, I am reverting.

79.182.215.205 (talk) 23:11, 17 June 2012 (UTC)

You are intentionally inserting material that is not in the source, against our core policy of verifiability. I would suggest you stop breaking our rules. Yobol (talk) 23:13, 17 June 2012 (UTC)

According to the rules, "Basic arithmetic, such as adding numbers, converting units, or calculating a person's age, is allowed provided there is consensus among editors that the calculation is an obvious, correct, and meaningful reflection of the sources. See also Category:Conversion templates."

What I did counts as converting units.

Do you think that the calculation not obvious, or not correct, or not meaningful reflection of the sources?

PS, You deleted more than you complained about. That gives me the impression, that you didn't think about your deletion, and acting on impulse instead of reason. I am open to reason. 79.182.215.205 (talk) 23:27, 17 June 2012 (UTC)

Converting units such as meters to centimeters, which is a completely different scenario than this. Someone trying to find "equivalent dose" in the cited article will be unable to find it, because there is no mention of it in the entire article. You cannot cite a source for something that is not in it. When someone objects, you discuss with them, or follow the dispute resolution process to get consensus. You do not bulldoze your way through trying to get your version in, like you have been doing. That way lies you being blocked from editing here. Yobol (talk) 23:33, 17 June 2012 (UTC)

The equivalent dose is well known, and have a Wikipedia article, which is linked in, and I trust all required references are there. Since you want a reference, and can't search by yourself, or read the linked wikipedia article, I have found for you the following text book which state: "For X rays, the radiation-weighting factor is equal to one; so the equivalent dose in Sv units is equal to the absorbed dose in Gy."

I am new to Wikipedia, but I think that having correct information in such an important matter is far more important than any rules, and warrant WP:IAR. That said, I am reasonable, and if you show reason, and change only what you find wrong, instead of just deleting everything, then I would most certainly discuss it with you, and perhaps accept. But when I see that you change correct stuff to incorrect stuff, and delete also things that you can verify, and not just things that you can't verify, excuse me, but my respect to that particular edit is not high.

79.182.215.205 (talk) 23:51, 17 June 2012 (UTC)

I have reverted. You are welcome to insert the source for the unit conversion, where ever you find it necessary, or open a case about it at the WP:DRN, which ever you like.

79.182.215.205 (talk) 23:57, 17 June 2012 (UTC)

References

See also

The see also section included:

• Tomosynthesis
• Virtopsy
• Xenon-enhanced CT scanning
• X-ray microtomography
• MRI versus CT
• Biological effects of ionizing radiation
• Dosimetry
• DNA damage
• Harmful mutations
• Radiation induced cognitive decline
• Radiation therapy

The last four entries were removed. Edit summary state "remove POV pushing".

WP:SEEALSO state "The links in the "See also" section do not have to be directly related to the topic of the article, because one purpose of the "See also" links is to enable readers to explore topics that are only peripherally relevant."

I think that the last four links are related or are peripherally relevant. I ask this deletion to be explained further or reverted.

79.182.215.205 (talk) 12:46, 19 June 2012 (UTC)

Those additions appear to be POV pushing about the risks of CT scans against due weight expected; for example, instead of just linking mutations, you link the internal "Harmful mutations" instead and internal link to DNA damage instead of DNA. Yobol (talk) 12:49, 19 June 2012 (UTC)

I think that if peripherally relevant is allowed, then arguments about due weight are not appropriate.

Since a link is short and can't be shorter, its weight is fixed, and due.

Eliminating a link from the "See also" section with an argument that it is "POV pushing" is a violation of NPOV.

79.182.215.205 (talk) 14:26, 19 June 2012 (UTC)

Eliminating inappropriate links is good editorial decision making. If we included any and all links that might be "peripherally relevant" the list would be thousands of links long. We have to use common sense; in this case, having multiple links that describe safety risks when one (biological risk from ionizing radiaiton) is the most relevant seems much too much. I await outside input as we will likely have to agree to disagree about the appropriateness here. Yobol (talk) 16:27, 19 June 2012 (UTC)

There's no point providing links to articles that have already been linked in the article body. I am particularly weary of the way in which piped links were used in this particular instance. JFW | T@lk 19:52, 19 June 2012 (UTC)

JFW, none of the links that were removed appear in the article.

79.182.199.172 (talk) 21:19, 19 June 2012 (UTC)

But they easily could be. JFW | T@lk 21:23, 19 June 2012 (UTC)

Really? Do you really think that I could insert somewhere a reference to radiation therapy, DNA damage, Harmful mutations, or Radiation induced cognitive decline, without that the people who own a CT scanning facility would try to delete it?

79.182.199.172 (talk) 23:55, 19 June 2012 (UTC)

Cognitive decline - Adverse effect

The following is the deleted Cognitive decline section, which was deleted due to not mentioning CT in the refs:

"Studies showed that radiation of ionizing radiation caused cognitive problems. Radiation of 60-310 mGy at the 8 to 15 weeks of gestation, or of 280-870 mGy at the 16 to 25 weeks of gestation caused mental retardation. Radiation of 100 mGy to the head at infancy caused cognitive deficits. Radiation of 1300-1500mGy to the head at childhood caused schizophrenia, and lowered IQ scores. Exposure of adults to 150−500 mSv caused cerebrovascular pathology, and exposure to 300 mSv caused neuropsychiatric, neurophysiological, neuroimmune, neuropsychological, and neuroimaging dose related effects."

First, CT was mentioned in one of the refs:

"The dose delivered to the brain of an infant during computed tomography of the skull is around 120 mGy."

"External radiotherapy to the head of infants with dose levels that overlap those from computed tomography may adversely affect intellectual development."

"Irradiation of the brain with dose levels overlapping those imparted by computed tomography can, in at least some instances, adversely affect intellectual development. Although formal diagnostic protocols do not advocate computed tomography in cases of minor head injuries, clinical practice dictated by legal and financial considerations does not always adhere to these protocols. The risk and benefits of computed tomography scans in minor head trauma need re-evaluating."

Second, this proves, that the experts opinion is that what matter for cognitive decline is the absorbed dose in Gray units, and not the protocol of the administration of the radiation dose, be it radiotherapy or CT.

Third, the other refs also include evidence of cognitive decline with absorbed dose overlapping those imparted by computed tomography, and thus should be included.

Forth, the other refs also include evidence of cognitive decline from various administration protocols of the absorbed dose, thus also proving that the administration technique is not relevant. — Preceding unsigned comment added by 79.182.215.205 (talk) 17:47, 15 June 2012 (UTC)

Please present appropriate secondary sources per WP:MEDRS, to establish WP:weight. Yobol (talk) 17:52, 15 June 2012 (UTC)

"DO LOW DOSES OF IONIZING RADIATION AFFECT THE HUMAN BRAIN?" is a secondary source for radiation induced cognitive decline, as it review many studies in the matter.

79.182.215.205 (talk) 18:48, 15 June 2012 (UTC)

That article seems to be studying radiation accidents, not medical procedures. What is your proposed edit in this article, and what text in that source are you proposing to use to support that edit? Yobol (talk) 19:01, 15 June 2012 (UTC)

The source is not pubmed indexed. And just as a heads up not all secondary sources are high quality. We prefer to use high impact journals with good peer review. Doc James (talk · contribs · email) 19:07, 15 June 2012 (UTC)

Did not realize it wasn't MEDLINE indexed. That is a huge red flag, and would wait for a better source before discussing this further. Yobol (talk) 19:08, 15 June 2012 (UTC)

1. Why does it matter where source is indexed or published?
2. The paper was made by Dept of Radiation Psychoneurology, Institute for Clinical Radiology, State Institution "Research Centre for Radiation Medicine of Academy of Medical Sciences of Ukraine". If you think that they are not an appropriate source please explicitly say so and explain why.
3. My proposed edit is the edit that was deleted. The statements in that edit are from this paper review of other papers. The other papers include pubmed indexed papers IIRC, and included medical procedures, not just radiation accidents.
4. The other papers should be accepted also as facts determined from primary sources. — Preceding unsigned comment added by 79.182.215.205 (talk) 20:13, 15 June 2012 (UTC)

Sources for medical information need adequate peer review. Articles published in non MEDLINE indexed journal, in my experience, tend to not be adequately peer reviewed and of poor quality. If it is an important aspect that should be in this article, it should not be a problem finding another source that complies with MEDRS to use. Yobol (talk) 20:18, 15 June 2012 (UTC)

Here are some of the articles, that I found in pubmed: "Long-term cerebral effects of small doses of x-irradiation in childhood as manifested in adult visual evoked responses.","Threshold for radiation-related severe mental retardation in prenatally exposed A-bomb survivors: a re-analysis.", and this in cancer.gov:"Late Effects of Treatment for Childhood Cancer".

79.182.215.205 (talk) 21:36, 15 June 2012 (UTC)

The first two are primary articles and not appropriate. The 3rd does not discuss CT scans as far as I can tell. Please limit the suggestions to MEDRS compliant sources that discuss CT scans. Thanks. Yobol (talk) 21:40, 15 June 2012 (UTC)

Why are the first two articles not appropriate? They are in pubmed like you required. The third article discuss cognitive effects of radiation from radiation therapy. In some cases CT emit radiation of the range of a radiation therapy session.

21:46, 15 June 2012 (UTC) — Preceding unsigned comment added by 79.182.215.205 (talk)

Here is a pubmed index of "Effect of low doses of ionising radiation in infancy on cognitive function in adulthood: Swedish population based cohort study." and of a secondary article referring to it "Low radiation doses; are they harmful in infancy?".

79.182.215.205 (talk) 22:09, 15 June 2012 (UTC)

They are primary studies, and therefore do not deserve WP:WEIGHT to be discussed. I get the sense that you want to include this information (for whatever reason) and are now trying to justify it, rather than finding high quality sources and summarizing them and letting the sources dictate what should be in the article. That is not the appropriate way to write a good encyclopedia article. Yobol (talk) 22:22, 15 June 2012 (UTC)

I just don't understand how you rate the articles. This one is secondary "Low radiation doses; are they harmful in infancy?", why do you say that it is primary? How about the following one, which pubmed tag as a review? "Radiation-related brain damage and growth retardation among the prenatally exposed atomic bomb survivors.". Aren't reviews considered good? — Preceding unsigned comment added by 79.182.215.205 (talk) 23:10, 15 June 2012 (UTC)

The first is an editorial (not a review article) published in an obscure journal; while technically secondary, per MEDRS we prefer reviews (preferably systematic reviews, but literature reviews can be good as well) and not editorials, especially ones in obscure Greek journals. The second is a review, but of prenatal exposure to the atomic bomb, and not CT scans. At some point you need to find high quality reviews, preferably in high impact journals, that speak about CT scans (such as NEJM). That you seem intent on throwing out poor source after poor source unfortunately speaks again to the fact that you seem determined to add specific information regardless of what the high quality sources tell us we should be adding. Yobol (talk) 23:17, 15 June 2012 (UTC)

How do you determine if an article is a review, or a systematic review, or a literature review, or an editorial? How do you know if it is from a good journal?

First you said that the article I found is no good because it is primary, and it have to be secondary to be good, then when I found a secondary article, you said that it is no good, and for it to be good it has to be pubmed indexed, then I found a pubmed indexed article, and you tell me oh right, it is pubmed indexed, but it is no good because it is from Greece. Give me a brake. I honestly think, that the sources I found are good, you say they aren't because of this or that, and I find a new article, and you find a new reason to trash it. Maybe you are right, and there is an obscured set of rules for identifying quality articles, but you haven't disclosed them rules, and for all I know, you (for whatever reason) may be inventing the reasons to reject articles on the fly. Secondly, the adverse effect are from ionizing radiation, which is present during a CT scan - see an other (hopefully a) review article, "Environmental factors associated with a spectrum of neurodevelopmental deficits.", that list ionizing radiation as a neurotoxicant.

79.182.215.205 (talk) 00:32, 16 June 2012 (UTC)

Finding the highest quality sources can be difficult, especially for those not experienced at looking at the medical literature. The first clue that a journal article is an editorial or a review is by reading it (you are reading the sources you are mentioning, right?) - journals often label them with "Editorial" or "Review" on the journal, and the tone/content is a big tip-off (editorials are usually less formal in tone than reviews). On the Pubmed page, one only needs look in the bottom of the page and hit the "Publication Type", and the type of article is usually there. The best journals usually have high impact factors; those who read medical journals regularly know the highest quality ones (NEJM, Lancet, etc); these impact factors can often be seen on the home page of the journal (or in the "About Us" section). The higher the number, the higher the impact that journal has, in general, in the medical literature and usually higher quality. Once again, to discuss adverse effects in this article, the source must discuss CT scans. You are more than welcome to get the input of other editors who edit medical articles (on the talk page of the Medicine Wikiproject if you would like other opinions. Once again, the best way to improve an article, is to find the best sources that discuss that topic and to summarize them. You seem to have started with a point you want to add to this Wikipedia page, and are now trying to find a source that will barely pass our guidelines to include that information. This is not the way to best improve the article. Yobol (talk) 03:46, 16 June 2012 (UTC)

Technical question - suppose I find an article, and its journal has an impact factor 7. Now 7 is just a number, and doesn't tell me 'this is a prestigious journal'. How do you translate 7?

An other question, suppose that I will not find an article that would satisfy you, and that nothing will be written at the wikipedia article, about the cognitive decline adverse effect of CT. Then, I will ask you, please find for me, an article that satisfy the same stringent requirements that you made, and that state that there isn't a cognitive decline adverse effect of CT, and suppose you would actually search, and find nothing. And I will tell you - well there is no proof that cognitive decline is not a side effect of CT, but if you don't write anything about it in the Wikipedia, it is like saying that it is known that there isn't a cognitive decline adverse effect to CT, which is not true, because it is not known. What would you say then?

79.182.215.205 (talk) 06:16, 16 June 2012 (UTC)

I got one with impact factor 3.15 - yea it is higher than 0.01 by so much, it must be excellent! - "Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure."

79.182.215.205 (talk) 06:58, 16 June 2012 (UTC)

That doesn't mention CT scans, and is a discussion of possible effects of occupational exposure of interventional radiologists. At this point, I'm getting of this merry-go-round, as you do not seem to get the underlying principle that to be a source on this page, it has to mention CT scans. Yobol (talk) 12:34, 16 June 2012 (UTC)

Forget about that for moment, does that article satisfy your quality requirements?

Now back to that, that is also a review of the effects of ionizing radiation on the brain.

CT produce ionizing radiation, and the ionizing radiation cause adverse effects.

If you would drink boiling water, you will get burned, even if you would drink it from a golden cup.

What you say to me is like saying, oh it is true that we have sources that show, that drinking boiling water cause severe burns, but we don't have sources that show, that drinking boiling water from a golden cup cause nasty burns, so until you find a source that say that drinking boiling water from a golden cup cause severe burns, we can't write in an article about a 'drinking boiling water from a golden cup', that its adverse effect include severe burns. Now that is just plain silly.

79.182.215.205 (talk) 19:48, 16 June 2012 (UTC)

Yobol, note that you didn't answer many of my questions above. I have asked the same question in the talk page of the medicine project, which you have referred me to, and someone there answered that it is OK to describe side effects to the ionizing radiation in an article about CT.

You have deleted the following subsection stating it is OR, however, all there is in there are statements that appear in reviews, and one statement from a study, which was described as from a study, which is in line with WP:MEDRS:

CT scans involve use of ionizing radiation, which is classified as a neurotoxicant. A 2004 cohort study concluded that irradiation of the brain with dose levels overlapping those imparted by computed tomography can, in at least some instances, adversely affect intellectual development. Prenatal exposure to ionizing radiation at the 8-15 and 16-25 weeks after ovulation was found to induce severe mental retardation as well as variation in intelligence quotient (IQ) and school performance. It is uncertain, if there exist a threshold, under which one or more of these effects, of prenatal exposure to ionizing radiation, do not exist. Cumulative equivalent doses above 500 mSv of ionizing radiation, which head CT scans can contribute to, were proven with epidemiological evidences to cause cerebro-vascular atherosclerotic damage.

Why did you consider it to be OR?

79.182.215.205 (talk) 20:39, 17 June 2012 (UTC)

What part of "the sources don't mention CT scans" don't you understand? Yobol (talk) 21:16, 17 June 2012 (UTC)

I understand and agree that "the sources don't mention CT scans", but I don't understand nor agree that sources must include a CT scan.

An other user NickCT seem to agree with me. He wrote to me, Saying something like "M involves using C at D concentrations which has been linked to A" should be ok. As long as all of those assertions are reliably sourced, even if M and A aren't specifically linked in literature, I don't know of any policy which would say you can't mention them together. Where. M=CT scan; C=ionizing radiation; D=some dose like 120mGy,350mGy, or 4000mGy; A=some adverse effect.

Do you have anything that support your opinion on this? — Preceding unsigned comment added by 79.182.215.205 (talk) 21:31, 17 June 2012 (UTC)

If you don't have anything that support your opinion, I will consider your argument as false, and reinsert the material.

79.182.215.205 (talk) 00:08, 18 June 2012 (UTC)

OK. Because you didn't provide any support, I will reinsert the section.

79.182.215.205 (talk) 00:55, 18 June 2012 (UTC)

And I've removed it because it's original research. If there's no source that mentions CT scans, then we don't synthesise a conclusion from multiple disparate sources. Here's what the policy states:

• Do not combine material from multiple sources to reach or imply a conclusion not explicitly stated by any of the sources. If one reliable source says A, and another reliable source says B, do not join A and B together to imply a conclusion C that is not mentioned by either of the sources.

Now please understand this civil warning: your behaviour here is verging on dispruptive editing. You need to accept the policies governing collaborative editing on Wikipedia, and desist from trying to insert your unsupported opinion. --RexxS (talk) 22:38, 18 June 2012 (UTC)

I support a civil discussion: Lets see, bellow is the new version of Cognitive effects:

CT scans involve use of ionizing radiation, which is classified as a neurotoxicant. A 2004 cohort study concluded that irradiation of the brain with dose levels overlapping those imparted by computed tomography can, in at least some instances, adversely affect intellectual development. Prenatal exposure to ionizing radiation at the 8-15 and 16-25 weeks after ovulation was found to induce severe mental retardation as well as variation in intelligence quotient (IQ) and school performance. It is uncertain, if there exist a threshold, under which one or more of these effects, of prenatal exposure to ionizing radiation, do not exist. Cumulative equivalent doses above 500 mSv of ionizing radiation, which head CT scans can contribute to, were proven with epidemiological evidences to cause cerebro-vascular atherosclerotic damage.

What there do you consider as A, and B of the rule that you quoted? What is the conclusion C? (Please reply for each statement)

79.182.215.205 (talk) 00:25, 19 June 2012 (UTC)

I didn't receive a reply, without a reply, I can't see how your point apply, and would have to revert.

79.182.199.172 (talk) 23:58, 19 June 2012 (UTC)

There is no need for a reply, as consensus here, on WT:MED and WT:OR is against you. We discuss up until consensus is reached, not until everyone agrees with that consensus. That you disagree with said consensus does not give you the right to go against it. Yobol (talk) 01:10, 20 June 2012 (UTC)

Yobol, consensus is just a matter of the people who are currently involved in the discussion. I can easily bring more people here, and out number you, and shift the consensus as I wish. Do you really want the discussion to be about the number of people supporting each side? I suggest that we keep the discussion focus on the content. If you don't have anything that make sense to say, I will consider it as you admitting in an error, and act accordingly.

79.182.199.172 (talk) 01:24, 20 June 2012 (UTC)

Local consensus does not overrule policy, and your edits breach WP:SYNTH which is policy. If you can't see that (A) CT scans use radiation; (B) radiation causes brain damage; therefore (C) CT scans cause brain damage is synthesis, then you really need to step away. No matter how you try to wrap it up, that is what you are writing, and yet you have no reliable source that reaches that conclusion with sufficient WP:WEIGHT to deserve inclusion. Your editing is tendentious and you have had sufficient warnings. If you do not now immediately desist from your disruption to these pages, I will take steps to remove your ability to edit here. --RexxS (talk) 02:30, 20 June 2012 (UTC)

SYNTH is not a policy

The (A),(B),(C) that you wrote don't appear anywhere in the discussed text.

Please see WP:BOLD in order to learn about the editing process.

79.182.199.172 (talk) 02:44, 20 June 2012 (UTC)

Wow, I just read this whole section and while I have no opinion on the brain damage issue and certianly do not advocate lessining MEDRS. I do, however, believe that requiring a specific mention of CT Scans for radiation effects in the article is, in this case, incorrect. The causitive agent is ionizing radiation whether from a CT scan or from some other source. It is disingenous to say that the radiation from at CT is unique or special in some way. I do not see that (general statement that radiation causes) ==> (radiation from CT causes) is synthysis. @Rexx I think you might be missing the point that (CT Scan) == (Radiation)for the purpose of this discussion unless there is something that makes the radiation from a CT Scan different from other ionizing radiation Maybe you or someone else asserts that CT Scans use a specific energy spectrum that is more begnin :), and should be considered as its own kind. If this, or something similar is the basis for not equating the two I believe an explanation of that would help the IP editor. I believe the whole purpose of the sievert is to level out diferences of source isotope / radiation type.) Jbhunley (talk) 16:07, 20 June 2012 (UTC)

There are a large number of excellent sources on the topic of the adverse effects of CT imaging. We use many of them already. One cannot simply take studies that look at large doses of radiation from radiation therapy or nuclear explosions and say that the same is true for CT without references that make that connection. Whether or not the dangers of radiations are linear is disputed. And units are less than ideal (the Sievert is an attempt to level out the differences which is different than saying that it does). We are not here to do original research. Doc James (talk · contribs · email)(please leave replies on my talk page) 16:44, 20 June 2012 (UTC)

My expertise is more in physics than in medicine, so I'm well aware that a CT scan exposes the body to electromagnetic radiation. However, even I know that the interaction of high-energy photons with the human body is exceedingly complex, and so are the mechanisms that the body employs to repair damage. If it were the case that CT scans were producing a significant amount of damage in the way that IP79.182 is theorising, then I am absolutely certain that good quality reviews would exist describing that significant risk. The fact that none of the major reviews already cited make the link: (CT Scan) == (Radiation), therefore {CT Scan) => (Significant Damage) is a big red flag. In Wikipedia - and particularly in medical claims - there should never be any need to make those sort of syntheses ourselves. If an effect exists, then there should be no problem finding good quality sources describing it, otherwise we must assume that it is insignificant and not worth mentioning per WP:UNDUE.

It seems to me that IP79.182 has come here with an agenda (that CT scans are dangerous), and has been synthesising from primary studies to support that belief in exactly the way that WP:MEDRS requires us not to. What needs to be done is to read all of the quality secondary sources first and only then to summarise them in a balanced, neutral manner. I have little doubt that that has been the route taken by the experienced members of WikiProject Medicine, Doc James and Yobol, who are the principal contributors to this article. I therefore have to respectfully disagree with your assertion that we don't need sources that describe the radiation effects of CT scans. --RexxS (talk) 17:05, 20 June 2012 (UTC)

I shall bow out of this. It is too charged a subject. I would however suggest that, when dealing with appropriate WP:MEDRS that someone might want to find some sources that say either sievert for sievert comparasons are appropriate or not appropriate and why. That will put the discussion to bed once and for all. It would also be of great use to the readers of this article. Jbhunley (talk) —Preceding undated comment added 21:16, 20 June 2012 (UTC)

I will be editing and adding this section back to the article. I have seen enough user intimidation here. Any info about adverse effects that I add will be sourced. I do not need your permission or your consensus to do this. If you edit or move or delete what I add, assuming it was well sourced, I will take appropriate and immediate action against you. I don't care who you are, or how much you have edited this article in the past. I hereby declare here that I have no private interests in favor of or against the topic of this article. If you do comment below, I appreciate if you first make a similar declaration. If, however, you do have a commercial interest in favor of the topic of the article, such as if you are a medical professional or student, I advise you to completely refrain from removing content from the section on adverse effects because your bias will be obvious. --IO Device (talk) 02:34, 21 June 2012 (UTC)

If what you add is supported by high quality sources and pertains to CT imaging I am sure no one will have problem with it. Might be good to take into account these comments here though [10] Doc James (talk · contribs · email)(please leave replies on my talk page) 02:57, 21 June 2012 (UTC)

References