Abstract
In patients with mammary carcinoma, irradiated postoperatively on the parasternal regions, prospective dose calculations for different fractionation schedules have been performed with the CRE formula. The biologic radiation effect on normal tissue was recorded by reflectance spectrophotometry of skin erythema and pigmentation. The right side received 4 050 R in 25 days, the left side 4 390 R in 47 days with a gap of 3 weeks. A compensation for the gap with 8 per cent of the total exposure was found to be adequate. The smallest exposure difference that could be clearly discriminated visually and with spectrophotometry was recorded in a special series and was found to be 6 to 7 per cent.