Collimator Jaws

Collimator jaws are precision-engineered, adjustable metal components within a collimator system, typically used in radiation therapy and imaging equipment. They function as movable barriers or shutters that physically limit and shape the beam of radiation (such as X-rays or particle beams) by moving independently along orthogonal axes to create rectangular or irregular field apertures. Their primary role is to precisely control the size, shape, and direction of the radiation field to match the treatment or imaging target while minimizing exposure to surrounding healthy tissues.

Collimator jaws operate by mechanical or motor-driven translation along guide rails or tracks. They are positioned symmetrically in pairs (typically two pairs for X and Y axes) relative to the beam central axis. A control system moves each jaw pair independently based on input parameters (field size, shape). The jaws absorb or block radiation outside the desired aperture, with their inner surfaces often tapered or shaped to minimize penumbra (the fuzzy edge of the radiation field). In multi-leaf collimators (MLCs), individual leaves function similarly but allow more complex shapes.