Written by Greg Arnold, DC, CSCS. CT scanning creates radiation exposure 1000 times as much as a chest x-ray, but only 35% discuss these risks with their doctor.
Of the many advances in modern medicine over the decades, from vaccines to prescription medications to surgical techniques, medical imaging has become very important in diagnosing disease. While x-rays have been used since the early 1900’s (1), computed tomography, also called “CT Scanning” or “CAT Scanning”, has been used since the 1970’s and is regarded as “the greatest innovation in the field of medical radiology since x-rays” (2), ranks as one of the top five medical developments in the last 40 years, and has proven so valuable as a medical diagnostic tool that the 1979 Nobel Prize in Medicine was awarded to the inventors (3).
Where x-rays produce one picture, computed tomography produces “slices” of areas of the body, like the slices in a loaf of bread, giving a much more complete picture inside the body and allows for a variety of diagnostic and therapeutic purposes (4).
But computed tomography does come with possible health risks, including radiation exposure that can increase cancer risk as well as skin reddening (erythema), skin tissue injury, hair loss, cataracts, and potentially, birth defects (if scanning is done during pregnancy) (3). Now a new study (5) suggests that many patients are not only unaware of the risks of computed tomography, but very few are informed of these risks by their doctor.
In the study, 217 patients in a veterans’ medical facility undergoing a computed tomography scan were divided into 2 groups: those who knew that computed tomography produced a higher exposure to radiation than traditional x-ray scans and those who did not. They were then further divided into another 2 groups: those who had a discussion with their doctors about the radiation risks of computed tomography and those who did not. An annual radiation limit is usually set at 20 millisieverts and lifetime radiation limit is 400 mSV. A typical chest CT exposes the body to 5-7 mSV of radiation compared to a chest X-ray which exposes the body to 0.02 mSV of radiation.
The researchers discovered that 1 in 3 patients (35% of patients) discussed the potential risks of the test with their health care provider while less than 1 in 5 patients (17%) reported having a shared final decision with their doctor on whether to have the scan as well as discussing the potential risks and benefits with their doctor (p < 0.05). A majority of the patients (62%) believed that the final decision to undergo a computed tomography scan was their doctor’s and not their own (p < 0.05). (6,7).
The researchers called this lack of communication between doctor and patient “problematic” since the risk of developing cancer from the radiation associated with a single scan has led to calls for mandatory informed consent (8).
They did admit that this was a small study of a specific population demographic but stated that “Correcting the lack of knowledge and the lack of communication about the potential harms of imaging tests—thereby enhancing shared decision making—should be part of any attempt to curb imaging overuse.”
Source: Caverly, Tanner J., et al. “Weighing the potential harms of computed tomography: patient survey.” JAMA internal medicine 173.7 (2013): 588-590.
© 2013 American Medical Association. All rights reserved.
Posted May 13, 2013.
References:
- “Medical X-rays” posted on the FDA website.
- “Computed Tomography Its History and Technology” – Siemens Medical Company, accessed online April 2, 2013.
- “What are the benefits of CT scans?” press release from theAmericanCollegeof Radiology and the Radiologic Society of North America posted on Radiology.org
- “Computed Tomography” posted on the FDA website.
- Caverly TJ. Weighing the Potential Harms of Computed Tomography: Patient Survey. JAMA Intern Med 2013 Apr 8:1-2. doi: 10.1001/jamainternmed.2013.2918.
- Godwin J. D, et al., Lifetime exposure to radiation from imaging investigation. Can Fam Physician 2006;52:976-977.
- Furlow, B (2010 May–Jun). “Radiation dose in computed tomography.” Radiologic technology 81 (5): 437–50.
- BaerlocherMO,DetskyAS.Discussing radiation risks associated with CT scans with patients. JAMA. 2010;304(19):2170-2171.
