Figure 4

Monitoring of treatment response after stereotactic radiosurgery. A patient with known metastatic melanoma underwent treatment to a left frontal lesion (A) and at 3 months (B) the characteristic changes of a blurred margin and necrosis followed by formation of a glial scar at 6 months (C) are seen. However in a similar appearing patient (D) with a right parietal lesion from metastatic renal cell carcinoma the lesion shows more florid changes at 3 months (E) with increased contrast enhancement at the margins and the possibility of progression as opposed to radionecrosis is raised. Multi-modal techniques described in the text may show promise in deciding how to proceed at this stage. The patient was well and on monoclonal antibody chemotherapy, with observation the lesion eventually regressed at 6 months (F) and is currently stable.