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Radiation
For many people, the term radiation is linked to atomic bombs, cancer and death. Even without these associations, ionising radiation in the form of X-rays is frightening. Acute exposure to X-rays cannot be sensed in any way, yet can be lethal within days or weeks if received at a high enough dose. There is clearly good reason to be concerned about unnecessary exposure to X-rays. In diagnostic imaging, balancing this danger is the benefit that can be realised from the use of these X-rays. When a group of leading general internists was asked to rank 30 medical innovations by the most adverse effect on their patients if the innovation were unavailable, the most important innovation ‘by a considerable margin’ was MRI and CT scanning.1 MRI does not use ionising radiation, but CT scanning is more widely available, can be completed in under 10 s compared with 20–30 min for MRI, and is the imaging modality of choice for acute trauma to the head or abdomen and for evaluation of the lungs.
How can your concern about radiation risk hurt your patient? Simply put, by not doing an imaging study that could benefit the patient more, or by unduly compromising image quality in an effort to reduce radiation dose. The following are 10 common ways that a medical caregiver can wrongly assess the risk : benefit of imaging to the detriment of his or her patients.
Overweighting the risk of radiation
The risk is very, very low. The lifetime attributable risk of cancer mortality to a 10-year-old from a 3 mGy average organ dose (similar to that from a body CT scan) is approximately 1/3000 for a girl and1/4700 for a boy, using the Biological Effects of Ionising Radiation VII estimates.2 This compares to the 1/5 probability, without additional radiation exposure, of dying of cancer for a typical person …
Footnotes
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Competing interests None.
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Provenance and peer review Not commissioned; internally peer reviewed.