Design and production of wax compensators for electron treatments of the chest wall

Abstract

The primary aim of electron treatment planning for the post mastectomy chest wall is to encompass the volume between the skin surface and the lung-rib interface while limiting dose to the lung. Electron energies for treatment of the chest wall are chosen based on the thickness of tissue between these two areas. Surgical defects or surface irregularities often result in differing thicknesses of tissue across the treatment volume, and patient-specific compensation is necessary to achieve the desired dose distribution. This is true whether the treatment plan is designed using fixed or rotational electrons to treat the chest wall. These clinical requirements are often met using custom shaped wax of varying thickness which conforms to the chest surface. This paper will discuss the treatment planning process used to design these compensators, creation and use of an exact duplicate of the patient's chest wall to aid in the production of these compensators, the production process itself, and verification of the completed compensator.