[RECIST and the radiologist].

Biomedical imaging makes it possible not only to diagnose and stage cancer, but also to follow up patients and evaluate the response to treatment. RECIST (Response Evaluation Criteria In Solid Tumors) provides a method to monitor the response to treatment based on one dimensional measurements of tumors obtained with reproducible imaging techniques like CT, MRI, and PET. The metabolic changes induced by new treatments modify the biology and behavior of the tumor; occasionally, there is a discrepancy between the patient's clinical condition and the response measured by RECIST, which indicates that functional tests need to be included in the evaluation of the response to treatment. The objective is to review the RECIST criteria to include the contribution of functional imaging to enable the efficacy and effects of the treatment in patients with solid tumors.