Design And Analysis Of Proton Heavy Ion Radiotherapy Chair

In recent years,the proton heavy ion radiotherapy is widely used as a new type of radiotherapy which can be orientated,quantitatively and accurately controlled.Because of the proton heavy ion beam accelerator can’t be moved,fixed beam radiotherapy is used.For patients with head and neck tumors,lung tumors,orthopnea,sitting posture radiotherapy is necessary.However,there is no proton heavy ion radiotherapy chair dedicated to the fixed beam treatment room for sitting radiation therapy.Currently,thermoplastic film is used for head and neck fixation,but it takes a long time,poor universality,uncomfortable.In this paper,a proton heavy ion radiotherapy chair with head and neck positioning function is designed for posture adjustment and head and neck positioning of patients in fixed beam radiotherapy room,so that the fixed beam of proton heavy ion radiation can be used to irradiate the tumor from different directions.It also can improve the efficiency,versatility and comfort of head and neck positioning.Based on the analysis research status of radiotherapy equipment at home and abroad and the need of proton heavy ion radiotherapy for patients’ posture,the design criteria of proton heavy ion radiotherapy chair is proposed.The U-TRIZ theory is used to analyze the whole scheme of the position adjustment mechanism.According to this scheme,a position adjustment mechanism with6-DOF is designed.Considering the principle of ergonomics,a head and neck positioning device is designed by analyzing the parameters of human head and neck.The device is universal and can be used for head and neck positioning of patients with various body types.The structural diagram of the treatment chair position adjustment mechanism is established for analyzing the chair,obtain the relationship between the length of the branch rod with the adjustment angle by analysis positive and negative kinematics of the XY angle adjustment module.Using MATLAB to solve the reachable position of each positioning bracket of the head and neckpositioning device,the results show that the position of each positioning bracket can satisfy the positioning requirements.ANSYS was used to analyze the stiffness and strength of several limiting situations of the chair posture adjustment mechanism and head-neck positioning device,the results show that the deformation of the attitude adjustment mechanism and the head and neck positioning device meet the radiotherapy requirements.The prototype of head and neck positioning device for proton heavy ion radiotherapy was fabricated and assembled,the experimental study was carried out,and the range of motion of each positioning module was measured.It verified that each positioning module can reach the position of the operation requirement and the positioning is reliable.From the perspective of ergonomics,an evaluation experiment is made on the prototype of the positioning device.The results show that the neck positioning device designed to meet the proton heavy ion radiotherapy of head and neck posture positioning requirements.