Collimator
Pronunciation: KOL-ih-may-ter
A beam-shaping device that defines the shape and size of the radiation beam before it reaches the patient.
Full Definition
A collimator is a critical component of radiation therapy equipment that shapes and restricts the radiation beam to match the intended treatment area. Primary collimators consist of heavy metal blocks or jaws that can move to create rectangular fields, while secondary collimation may involve multileaf collimators for complex field shaping. The collimator system is essential for protecting healthy tissue while ensuring adequate dose coverage of the target volume, and its position is typically specified in treatment plans.
Usage
Usage note: Distinguished from multileaf collimator (MLC), which provides more sophisticated beam shaping.
In Context
- "The collimator rotation was set to 15 degrees to optimize the field orientation for this treatment." — Treatment verification record
- "Primary collimator settings must be verified against the prescription before beam delivery." — Quality assurance checklist