Beam Spoiler

Full Definition

A beam spoiler is a low atomic number material, typically acrylic or polystyrene, placed in the path of an electron beam to reduce its energy and modify the dose distribution. Spoilers are used to create more uniform dose distributions for irregularly shaped treatment volumes, particularly in total skin electron therapy or when treating superficial targets with underlying critical structures. The spoiler increases the dose rate while reducing the practical range and therapeutic ratio of the electron beam.

Usage

Usage note: Distinguish from beam hardening filters used with photon beams.

In Context

• "A 1-cm acrylic beam spoiler was used to improve dose uniformity across the chest wall treatment field." — Treatment technique report
• "The beam spoiler configuration required commissioning measurements to verify dose calculation accuracy." — Physics documentation