Electron arc therapy of the postmastectomy prosthetic breast.

Abstract

Reconstructive surgery of the postmastectomy breast presents new challenges to postoperative radiation therapy. This paper evaluates the dosimetric significance of oblique incidence of the electron field on the reconstructed mound during arc therapy. Using film densitometry, the relative dose distributions resulting from electron arc therapy incident on phantoms simulating the breast and chest wall dimensions of an actual patient are evaluated. Irradiation of the breast phantom in normal supine position results in constriction of the dose distribution at the junction of the reconstructed mound with the chest wall. Angulation of the phantom to provide a more normal incidence of the electron beam during arc reduces the constriction by minimizing obliquity of the incident electrons. These measurements suggest that, with proper positioning of the patient relative to the incident electron beam, electron arc therapy may be used as an alternative treatment technique for treatment of the postmastectomy reconstructed breast and chest wall.