Bone-density test Aside from those who are at high risk for weak bones, women should wait until they are 65 to have their bone density measured. Younger women are unlikely to have outright osteoporosis, and while the scan may detect mild bone loss (osteopenia), the risk of a fracture is low and the drugs that may be prescribed to treat this condition carry side effects and haven't proved to be highly beneficial in these cases. CT scan or MRI, for headaches Most of the time a careful medical history and a neurological exam (e.g., measuring reflexes) can diagnose the problem. And CT scans involve a hefty dose of radiation. EKG or exercise stress test Hooking up to an electrocardiogram (EKG) and/or taking an exercise stress test makes sense if you have symptoms of heart disease or are at high risk, but those at low risk who are just looking for reassurance may get inaccurate results that can lead to further testing and overtreatment with drugs. Imaging for lower-back pain You don't want to skip an X-ray, CT scan or MRI if there are signs of a severe problem (a history of cancer, fever or pain that lasts several weeks), but lower-back pain often gets better in about a month. PET/CT for cancer screening in healthy people The likelihood of finding cancer in healthy adults using these screening methods is extremely low, according to the Society of Nuclear Medicine and Molecular Imaging. Source
