Serial ultrasonic measurements performed on 85 melanoma patients who were treated with radioactive plaques and followed for up to 141 months revealed that no 2 patients had identical patterns of change. Eighty-two of the patients were categorized into one of four patterns after treatment: Type D (decrease in height, 57 patients), Type S (same height, 12 patients), Type I (increase in height, 9 patients), and Type RG (tumour regrowth, 4 patients). The calculated mean total change in tumor height for Type D was 1.92 mm at 6 months, 2.58 mm at 12 months, 2.97 mm at 24 months and 3.61 mm at 48 months. For Type I, the mean total change in tumor height was 0.80 mm at 6 months, 0.95 mm at 12 months, 2.28 mm at 24 months, and 3.0 mm at 48 months.