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[Positron emission tomography in evaluating the response to treatment of brain tumors, lymphomas and breast cancer].

Positron emission tomography (PET) with the glucose analogue (18)F-FDG is increasingly used to monitor tumour response in patients undergoing chemotherapy, radiotherapy or new therapeutic schemes including antiangiogenesis and molecular targeted cancer treatment. PET as a functional imaging technology provides timely, quantitative, cross-sectional, non invasive assessment of several biologic processes targeted by the above-mentioned therapies. Tests by the camera PET can be useful in distinguishing between radiation necrosis or scarring and tumour recurrence, thus evaluating response to therapy. The information provided by this technique is more sensitive and specific than that provided by conventional anatomic imaging modalities such as computerised tomography, magnetic resonance imaging or ultrasound and superior in evaluating the effectiveness of various treatment regimens early during therapy or after the completion of therapy. With this information in hand, physicians can modify ineffective therapy and consequently improve patient's outcome and reduce the cost of treatment. In the present review article we discuss the contribution of tests performed by the PET camera, mainly using (18)F-FDG as a radiotracer, in the evaluation of treatment response in patients with brain tumours, lymphomas and breast cancer.