For example, even the most modern scans cannot always pick up tiny areas of cancer. And occasionally other medical conditions give rise to similar results, making it difficult to decide what is and is not cancer. Doctors are trained to piece together information from different tests and examinations along with symptoms and medical history, and put all this information in context. For this reason, it is often best for the doctor to discuss test results with you personally. Usually only those tests are used which give the most helpful information about your condition.
Unnecessary tests can waste time and delay treatment.
However, if you are worried about whether you are having the right tests, talk this over with your doctor. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you contact. You will be asked not to eat or drink for at least four hours before the scan. Special liquids are often used to allow particular areas of the body to be seen more clearly on the scan. They may be given as a drink or an injection, or both.