Stereotactic Radiotherapy Equipment ISO Center Calibration Instrument Design

Isocenter is a mportant idea in the radiotherapist.Normally we put the nidus mark on the position of isocenter.At the time of treatment,the axis of beam must pass through the isocenter.So,the structure design of the stereo and targeted radiotherapy equipment should be layouted around the isocenter.Isocenter is a virtual spatial point.At the time of treatment,the body of patient should occupy the space,so we cannot put a noumenal Indicating device in this space.But the accuracy of the point is so important that we must put nidus mark restore to the point Accurately in the every treatment.So Electron linear accelerator have set 4 indication device of isocenter:(1)Laser Lamps;(2)Field lamp;(3)Ranging lamp;(4)Front Point.Based on the mark methods of isocenter in the world,there is no Mature method to use except for the front pointer,and most of the methods is manually operated.Based on the present situation,this paper describe a design of Accurate 6 dimension platform drived by Linear Actuator and controlled by microcontroller.,it realized a accurate method to indicate the isocenter and we can controll the device by remote.This paper firstly analysis the the background and the application value,then analysis the indicate methods of isocenter in the world,then it confirms the present situation and requirement,at last,it brings a new method to indicate the space of isocenter base on the requirement.The scheme designs a white cube model of side length 100 mm and a six dimen--sional motion platform.There is a 2 mm dense Tungsten alloy ball in the center of model for X-ray radiogram and exposure.In addition,there are four 1mm hole on the center of four vertical surface.For all light sensor could apparently detect the light when the hole shined by laser,we must install a lens in all hole.So the light sensor could monitor the luminance in realtime and display the value by led array on the platform.The platform installed 6 Linear Actuator with 6 DC motor,we receive the instruction by nRF905 module,then STM32F103 accords the instructions to drive corresponding DC motor to realize the 6 dimension motion.All told,the design innovative realize the accurated indicate of isocenter by nRF905 wireless technology and linear actuator,and Saving time and facilitates handling.