Henry Ford Hospital Medical Journal


Computer-generated depth-dose data was obtained for the region of overlap of the internal mammary and supraclavicular portals utilized in post-operative radiation therapy for carcinoma of the breast. A phantom arrangement was created and measurements were obtained and compared with computer-generated depth doses for this arrangement. The actual measured and computer-generated values agreed to within 3%. On the patients measured at the center of the overlap region, the dose was found to vary from 3323 rets to 2571 rets over a depth range of 2-6 cm. It is occasionally the practice to ignore small areas of overlap. The dose at the center of this region is significant even for small areas, and therefore, the corner should be blocked from one of the two fields.