The use of an optical outlining system for weekly on-set verification of patients with carcinoma of the breast.

The installation of an optical outlining system on both a simulator and treatment unit has enabled patient cross-sectional outlines to be measured throughout a radical treatment period of 5 weeks. Two studies were conducted to assess the reproducibility of positioning in treatments for breast carcinoma. The first study assessed changes in outline for 23 patients treated on a home-made tilt-board. Seven patients (32%) displayed a change in shape in excess of 1 cm during the course of treatment, which could have significant dosimetric consequences. The second study focused on the reproducibility of set-up using different tilt-boards. This included a further 19 patients treated using a commercial board, which is now in routine use.