Nuclear medicine exams save a lot of people unnecessary surgeries and help with diagnosis. Your doctor should know when the exam needed. Perhaps you are having abdomen pain, sonography and/or CT scan don't show anything. A gallbladder scan will show that the gallbladder is actually functioning correctly or not. Nuclear medicine bone scan will show areas of increase uptake in bone showing areas where there may be hidden bone cancer metastasis with out doing x-rays head to toe, also shows up things like arthritis and stress fractures. Tagged red blood cell scans will help locate sources of bleed for people who are losing blood but the doctor doesn't know where. Nuclear medicine has a scan they do that is for brain death, so that organ transplants can take place. Yes lots of people are scared of the word radiation,but in the case of diagnostic scanning the dosage is small. Risk vs benefit is always a question when working with radiation, that is why you cant just walk in and request a x-ray or exam yourself. The personal physician, the radiologist, and the technologist are all there to keep you safe and health.