Any suspicious findings in the physical exam or the lab test results will make your doctor want to find out what is going on inside your body. He or she could just look inside directly, either with special instruments or by opening up some area. But the first step usually involves the use of one or more devices that produce images of suspicious areas.
These "imaging studies" may show a tumor in a specific organ and the image will help your doctor assess its size and whether it has involved surrounding tissues.
If you complain of indigestion, for example, your doctor may suspect stomach cancer. This would lead to an x-ray or endoscopy of the upper gastrointestinal tract. Lower digestive tract complaints such as constipation or bleeding might lead to an x-ray or endoscopy to diagnose a possible carcinoma of the colon. Blood in the urine may lead to an x-ray of the kidneys to confirm a suspected tumor in the kidneys or bladder. And complaints of severe headaches, together with other symptoms of increased pressure in the head, may result in a CT scan of the head in search of a brain tumor.
Until fairly recently, radiography (x-ray) was the only imaging technique available. If x-rays couldn't answer critical questions in the diagnostic investigation, then a surgeon would have to open up the body to take a direct look. But new techniques have revolutionized the art and science of diagnosis. Some of the new techniques involve the use of x-rays, others do not.
X-rays This familiar imaging technique involves passing a small dose of electromagnetic radiation through a
