Wedge Filter
A beam-modifying device that creates a graduated dose distribution across the treatment field by preferentially attenuating one side of the beam.
Full Definition
A wedge filter is a beam modification device used in radiation therapy to create an angled or graduated dose distribution across the treatment field. Physical wedges are made of dense materials like lead or tungsten and are placed in the beam path, while dynamic wedges are created by moving the collimator jaws during beam delivery. Wedge filters are particularly useful for treating curved surfaces, matching adjacent fields, and compensating for missing tissue or irregular patient contours. The wedge angle describes the slope of the resulting isodose distribution.
Usage
Usage note: Distinguish between physical wedges (hardware) and dynamic/virtual wedges (software-generated).
In Context
- "A 30-degree wedge filter was used to improve dose uniformity across the chest wall." — Treatment planning note
- "The wedge filter orientation must be verified before each treatment delivery." — Treatment checklist