Identifying and diagnosing cancerous diseases is currently one of the main tasks of today's radiologist. Every year cancer is diagnosed worldwide in over 12 million people. Within a single year, 7 million people die from cancer worldwide.

The most commonly diagnosed cancers are lung, breast, and colorectal cancers. The most common causes of cancer death are lung, stomach, and liver cancers.

Besides identifying primary tumours, it is also very important that radiology identifies possible metastases in other organs such as the liver, bones, brain, etc. at an early stage. Today all this information is gained using imaging techniques. The radiologist thus plays an important part in the treatment of people suffering from cancer.

A further important task of the radiologist using imaging techniques is judging whether oncological treatment of the tumour's course has to be initiated. In this way, the radiologist is able to make a statement as to whether the targeted oncological therapy has achieved its goal or whether in the absence of a response it has to be further adjusted.

The total medical care costs for people with cancer are approximately 20% higher than those for heart or vascular diseases, which are the second leading causes of global health costs. These high costs, however, arise as the result of many different factors such as costs of medication and the various therapy options, nursing care, and a lesser proportion also due to the application of radiological techniques.

The radiologist has many different techniques at his disposal to identify neoplasias within the body.

In principle, there are techniques using or not using X-rays.