Intelligent Control Of Speed And Position In The Dynamic Multi-leaf Collimator

With the development of tumor radiation therapy technology and the clinical application matures of 3-dimension conformal radiotherapy, intensity-modulated radiotherapy, image guide radiotherapy, Radiotherapy as a kind of tumor treatment way, have been accepted by more and more doctor and patient. More patient need to radiotherapy. However, it is inefficient if develop the new radiotherapy technology in the tradition way, also the treatment effect is very bad. So the new equipment which helps the doctor and patient is very necessary, as more as tumor patient will be treatment as early.As an equipment to implement new technology of radiotherapy, Dynamic multi-leaf collimator plays a vital role. It can implement all of conventional radiotherapy, 3D conformal radiotherapy, intensity-modulated radiotherapy and image guided radiotherapy, improve treatment efficiency than the before nearly doubled, greatly reduce the workload of doctors and protect them effectively, reduce lead contamination and environmental pollution. At the same time, there is an increasingly high technical requirement for the advanced equipment. From the clinic effect of the dynamic multi-leaf collimator, the demands for motion control of leaves, as the most important part of the equipment, is especially higher. These leaves are tungsten alloy, very heavy, and the whole equipment is hung to the head of linac when treatment. So the motion control should take the weight of leaves and acceleration into account. The motion performance of leaves has a direct effect to radiation distribution in the patient body, so the fast acceleration and best dynamic performance are required so as to help improve the results of radiotherapy for lung tumor or other motion tumor. The Highly precise position control of leaves is important for the prostate patients. As import complete sets of equipment,dynamic multi-leaf collimator is very expensive, so developing new dynamic multi-leaf collimator to meet the new clinic requirements is more of an urgent need in market.The main topics of this research is the design of dynamic multi-leaf collimator speed and position intelligence control system to meet the demand of three-dimensional conformal radiotherapy, the intensity-modulated radiation therapy and imaging guide radiotherapy. The paper related to the requirement analysis of dynamic multi-leaf collimator, intelligence control system design, implementation and verification, especially, the design of the Cascade PID control and the adaptive feed forward control strategy based on CMAC. Through designing control system on the 54 intelligent servo motors, we completed position and velocity intelligent control of DMLC leaves. The result of the implementation of control systems is presented. And the position and velocity comparison with similar foreign products is done. The comparison results show our control system is successful and meet the design requirements. Finally, the adaptive control technology of dynamic multi-leaf collimator is explored, and its MATLAB simulation result is demonstrated.