These often involve exposure to ionizing radiation. The reasons for these repeated and unnecessary scans are not well understood, but probably include physician fear of missing a dangerous cause of headache and a desire to allay patient anxiety over possible missed abnormalities, especially when treatment is unsuccessful. In some cases, duplicate scans may be ordered because the physician is unaware of previous testing. The risk of unneeded testing may be especially high in the emergency department, where physicians are unfamiliar with the patient and fear missing serious causes of headache. In ordering diagnostic tests, though, the possible adverse

effects of testing must be balanced against the likely benefits to the patient. In particular, the potential adverse health effects of Carfilzomib research buy radiation exposure should be taken into consideration when ordering diagnostic testing for headache. In many situations, it is very unlikely that a Talazoparib mouse repeat imaging study of the head will identify any abnormality that will alter management. The radiation risks of CT scanning are not negligible. Younger people are at higher risk of radiation adverse effects than older people.

The authors of a recent review of the risks of diagnostic CT scans concluded, “In summary, there is direct evidence from epidemiologic studies that the organ doses corresponding to a common CT study … result in an increased risk of cancer. The evidence is reasonably convincing for adults and very convincing for children.”[8] A single this website CT scan of the head exposes patients to an average of 2 mSV of radiation, the equivalent of 8 months of background radiation.[9] A recently published article noted that 24 of the initial 45 Choosing Wisely recommendations concerned diagnostic

radiology tests or procedures. The authors suggested that this emphasis is appropriate in view of the known risks of radiation exposure. They noted that “if Choosing Wisely is successful and dissuades only nonindicated examinations, it may save lives in addition to money.”[10] One other professional society has also released a recommendation relating to appropriate use of imaging studies for headache. The American College of Radiology Five Things List includes a recommendation that states, “Don’t do imaging for uncomplicated headache.”[11] The AHS recommendation is more specific and limited to patients who meet diagnostic criteria for migraine. The committee did not find sufficient high-quality evidence to make a broader recommendation about headaches that do not meet criteria for migraine. Previous recommendations on chronic headache and neuroimaging found sufficient evidence to state that the incidence of imaging abnormalities in migraine patients is not greater than in nonmigraine patients, but for headaches that are not consistent with migraine, there is insufficient evidence to make a recommendation.[12] It is not easy to define what constitutes an “uncomplicated” headache.