Quality Assurance of IMRT

Intensity-Modulated Radiation Therapy (IMRT) differs from conventional therapy in that the intensity distribution of each field is non-uniform. This intensity distribution is typically determined by an optimization algorithm so that, when combined with other fields, an optimum dose distribution can be obtained. The delivery of an intensity-modulated field can be accomplished with a physical compensator, a special multileaf collmator (MLC) such as MIMIC, or a conventional MLC. To ensure accurate and safe delivery of IMRT in the clinic, it is prudent to implment additional quality assurance procedures to those that are already used for conventional therapy. In this wrok, we describe the procedures used in our hospital that are specific to the delivery of DVIRT with a conventional MLC.