Development Of Control System For Medical Multi-leaf Collimator

Malignancy is one of the serious diseases that threaten human health. Among thetherapeutic methods against tumors, radiation therapy has being used more widely. Toachieve the purpose of killing cancer cells in radiation therapy, high-energy rays are used toirradiate tumor lesions. As the high-energy rays will also affect the normal cells, the controlof irradiation area is particularly important. Multi-Leaf Collimator(MLC) is commonly usedto control the irradiation area in Radiotherapy equipments. In order to precisely control thearea, this paper develops a kind ofcontrol system for the MLC.MLC control system bridges the treatment service software and MLC. After receivinginstructions from treatment service software, MLC control system produces motor signalswhich are needed for the formation of irradiation area, meanwhile, the relevant sensorinformation in the MLC and treatment head is transmitted through the system. According tothe functional requirements, the MLC control system is divided into two submodule in thispaper, i.e., the data transmission module and signalprocessing module.As the MLC control system is used in medical equipment, nonreliable data may lead todeviation of radiation area, which will bring accident harm to patients. Based on this idea,we use the the PC104bus for the internal data transmission of the system, and the RS232serial standard for the outsider communication.Test results show that the MLC control systemcan form corresponding irradiationrange,but, the accuracy of irradiation range is not enough. Especially for the edge of the range. Inthe future work, we should consider the accuracycontrolof the leaf movement.