ABSTRACT
Introduction Radiological imaging plays a crucial role in cancer disease. It can be used to confirm the histological diagnosis, which is often made by image-guided biopsy and in the detection of local and distant disease at diagnosis. The diagnosis and accurate staging of cancer is imperative in determining whether potentially curative or palliative therapy is instituted. Radiological techniques can also be used during therapy to evaluate response to treatment. This can be done by comparing the pre-treatment (baseline) examination with subsequent examinations, thereby determining if the disease has responded to treatment, is stable, or has progressed. This may influence further treatment approach. Response evaluation by radiology is accurate with the use of traditional “cytotoxic” agents that kill cells and decrease tumor size. However with the newer “cytostatic” agents (e.g., anti-angiogenesis agents) the radiological tumor size may not change. The main difference between clinical practice and clinical trials is that in many clinical trials measurable disease of a minimum size at baseline is required and that pre-determined examinations with set imaging protocols within specific time frames relating to the administration of therapy are undertaken. The following sections summarize the common imaging modalities used in clinical practice and clinical trials.
