Design and physical properties of an Iris™ collimator for robotic radiosurgery

Abstract

Robotic radiosurgical treatments using more than one circular field size may confer improvements in plan quality and total monitor units for many cases when compared with single-collimator treatments, but delivery efficiency is diminished when fixed collimators are used to deliver such treatments owing to the need for multiple traversals of the robotic manipulator. We describe an Iris Collimator that allows the full range of circular field sizes to be used within a single robot traversal. The radiation and mechanical properties of this device are described, and a beam commissioning procedure is detailed. The device meets all of its design goals, and thereby offers the potential to greatly increase the clinical application of multiple field sizes for treatment delivery. © 2009 Springer-Verlag.