Multi-leaf Collimator Control System Design And Realization

MLC, for short of multi leaf collimator was widely used in radiation therapy field.The basic application of the MLC is to replace conventional blocking. The field-shaping functions served by these familiar and widely used procedures can be largely duplicated by leaf position sets stored on a computer file to form a desired field shape.The world famous therapy accelerator manufacturers have their own MLC products. But in our country, MLC technology was still stayed at a low level.In the postgraduate study period, the author had taken part in a MLC develop project.The aim of this paper is to provide basic information and to state fundamental concepts of MLC control system.In this paper, the structure and the working principle of multi leaf collimator for radiation therapy were introduced. The control system for the collimator was discussed in detail, including the single chip computer and its interface design, the dc motor PWM control, and the fuzzy control algorithm for high distance moving accuracy. The system has been successfully implemented in a homemade collimator.