A new technique for visualizing our body organs has drastically reduced the need for exploratory surgery to diagnose major illnesses such as cancer. The technique, which involves linking a sophisticated X-ray machine to a computer, is known as computerized tomography (or CT) scanning. Conventional X-ray techniques are relatively poor at showing detail in soft tissue and cannot show organs covered by bone. A CT scan gives a clear, 3-dimensional, colour image of all our body structures. CT scans have revolutionised many aspects of diagnosis and treatment of disease. Now surgeons have a clear idea of what they will find before the operation begins and in some cases surgery can be avoided.