User:Doc James/CT

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Linet, M. S.; Slovis, T. L.; Miller, D. L.; Kleinerman, R.; Lee, C.; Rajaraman, P.; Berrington De Gonzalez, A. (2012 Feb 3). "Cancer risks associated with external radiation from diagnostic imaging procedures". CA: A Cancer Journal for Clinicians. 62 (2): 75–100. doi:10.3322/caac.21132. PMC 3548988. PMID 22307864. {{cite journal}}: Check date values in: |date= (help)


Adverse effects[edit]

the benefits are typically greater than the risks when used for appropriate reasons.[1] , especially in children, the benefits that stem from their use outweigh the risk in many cases.[2]

Cancer[edit]

There is a small increase risk of cancer with CT scans[1] with this risk being slightly larger in children.[3] CT scans involve the use of 10 to 100 times more ionizing radiation than plain X-rays.[4] It is estimated that 0.4% of current cancers in the United States are due to CTs performed in the past and that this may increase to as high as 1.5-2% with 2007 rates of CT usage;[5] however, this estimate is disputed.[6]

These estimates are partly based on similar radiation exposures experienced by those present during the atomic bomb explosions in Japan during the second world war and nuclear industry works.[7] Estimated lifetime cancer mortality risks attributable to the radiation exposure from a CT in a 1-year-old are 0.18% (abdominal) and 0.07% (head) — an order of magnitude higher than for adults — although those figures still represent a small increase in cancer mortality over the background rate. In the United States, of approximately 600,000 abdominal and head CT examinations annually performed in children under the age of 15 years, a rough estimate is that 500 of these individuals might ultimately die from cancer attributable to the CT radiation.[2] The additional risk is still low: 0.35% compared to the background risk of dying from cancer of 23%.[2] Furthermore, certain conditions can require children to be exposed to multiple CT scans.[7]

One study indicated that radiation by CT scans is often higher and more variable than cited, and each of the 19,500 CT scans that are daily performed in the US is equivalent to 30 to 442 chest X-rays in radiation. It has been estimated that CT radiation exposure will result in 29,000 new cancer cases just from the CT scans performed in 2007.[8] The most common cancers caused by CT are thought to be lung cancer, colon cancer and leukemia, with younger people and women more at risk. These conclusions, however, are criticized by the American College of Radiology (ACR), which maintains that the life expectancy of CT scanned patients is not that of the general population and that the model of calculating cancer is based on total-body radiation exposure and thus faulty.[8]

CT scans can be performed with different settings for lower exposure in children, although these techniques are often not employed.[9] Studies support informing parents of the risks of pediatric CT scanning.[10]

Contrast[edit]

The old radiocontrast agents caused reactions in 1% of cases while the newer lower osmolar agents cause reactions in 0.04% of cases. [11]

The contrast agent may induce contrast-induced nephropathy.[4] This occurs in 2 – 7% of people who receives these agents with greater risk in those who have preexisting renal insufficiency,[4] preexisting diabetes, or reduced intravascular volume. People with mild kidney impairment are usually advised to ensure full hydration for several hours before and after the injection. For moderate kidney failure, the use of iodinated contrast should be avoided; this may mean using an alternative technique instead of CT. Those with severe renal failure requiring dialysis do not require special precautions, as their kidneys have so little function remaining that any further damage would not be noticeable and the dialysis will remove the contrast agent.

Hair loss[edit]

A few cases of temporary hair lose following multiple CTs in a short period of time have been reported.[12]

References[edit]

  1. ^ a b Hall, E. J.; Brenner, D. J. (2008 May). "Cancer risks from diagnostic radiology". The British Journal of Radiology. 81 (965): 362–78. doi:10.1259/bjr/01948454. PMID 18440940. {{cite journal}}: Check date values in: |date= (help)
  2. ^ a b c Brenner D, Elliston C, Hall E, Berdon W (February 2001). "Estimated risks of radiation-induced fatal cancer from pediatric CT". AJR Am J Roentgenol. 176 (2): 289–96. doi:10.2214/ajr.176.2.1760289. PMID 11159059.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  3. ^ Brenner, DJ (2010 Jan-Mar). "Should we be concerned about the rapid increase in CT usage?". Reviews on Environmental Health. 25 (1): 63–8. doi:10.1515/reveh.2010.25.1.63. PMID 20429161. {{cite journal}}: Check date values in: |date= (help)
  4. ^ a b c Hasebroock, K. M.; Serkova, N. J. (2009 Apr). "Toxicity of MRI and CT contrast agents". Expert Opinion on Drug Metabolism & Toxicology. 5 (4): 403–16. doi:10.1517/17425250902873796. PMID 19368492. {{cite journal}}: Check date values in: |date= (help)
  5. ^ Brenner DJ, Hall EJ (November 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}}: CS1 maint: date and year (link)
  6. ^ Tubiana M (February 2008). "Comment on Computed Tomography and Radiation Exposure". N. Engl. J. Med. 358 (8): 852–3. doi:10.1056/NEJMc073513. PMID 18287609.{{cite journal}}: CS1 maint: date and year (link)
  7. ^ a b Cite error: The named reference NEJM-radiation was invoked but never defined (see the help page).
  8. ^ a b Roxanne Nelson (December 17, 2009). "Thousands of New Cancers Predicted Due to Increased Use of CT". Medscape. Retrieved January 2, 2010.
  9. ^ Semelka, RC; Armao, DM; Elias, J, Jr.; Huda, W. (May 2007). "Imaging strategies to reduce the risk of radiation in CT studies, including selective substitution with MRI". J Magn Reson Imaging. 25 (5): 900–9. doi:10.1002/jmri.20895. PMID 17457809.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  10. ^ Larson DB, Rader SB, Forman HP, Fenton LZ (August 2007). "Informing parents about CT radiation exposure in children: it's OK to tell them". AJR Am J Roentgenol. 189 (2): 271–5. doi:10.2214/AJR.07.2248. PMID 17646450.{{cite journal}}: CS1 maint: date and year (link) CS1 maint: multiple names: authors list (link)
  11. ^ Drain, K. L.; Volcheck, G. W. (2001). "Preventing and managing drug-induced anaphylaxis". Drug Safety : An International Journal of Medical Toxicology and Drug Experience. 24 (11): 843–53. doi:10.2165/00002018-200124110-00005. PMID 11665871.{{cite journal}}: CS1 maint: date and year (link)
  12. ^ Imanishi, Y.; Fukui, A.; Niimi, H.; Itoh, D.; Nozaki, K.; Nakaji, S.; Ishizuka, K.; Tabata, H.; Furuya, Y.; Uzura, M.; Takahama, H.; Hashizume, S.; Arima, S.; Nakajima, Y. (2005 Jan). "Radiation-induced temporary hair loss as a radiation damage only occurring in patients who had the combination of MDCT and DSA". European Radiology. 15 (1): 41–6. doi:10.1007/s00330-004-2459-1. PMID 15351903. {{cite journal}}: Check date values in: |date= (help)
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