A Study on the Application of Two Different Position Fixation Devices in Radiotherapy of Tumor Patients
Objective To compare the effects of thermoplastic individual body pad combined with phantom,body frame fixation technology and phantom combined with body frame fixation technology on tumor radiotherapy setup error.Methods 52 patients were treated with thermoplastic individual body pad combined with phantom,body frame fixation technique(group A),and 58 patients were treated with phantom combined with body frame fixation(group B).Before radiotherapy,2 weeks and 4 weeks of treatment,simulated locator reduction was performed and images were collected(abdominal and pelvic tumors with less times of treatment were repositioned once before treatment and 2 weeks after treatment).The setup errors of X axis,Y axis and Z axis were compared and analyzed.Results The setup errors of Y axis and Z axis in group A were smaller than that in group B before radiotherapy and the second week of treatment(P＜0.05).The others were no significant differences(P＞0.05).The stratification of tumors in different parts were analyzed.In head and neck tumors,the setup errors of X axis,Y axis before radio-therapy,Y axis 2 weeks after radiotherapy and Y axis 4 weeks after radiotherapy in group A were less than those in group B(P＜0.05).The others were no significant differences(P＞0.05).In chest tumors,except X axis before radiotherapy and X axis direc-tion 2 weeks after radiotherapy,the setup errors in group A were less than those in group B(P＜0.05).In abdominal and pelvic tumors,the setup errors of Y axis and X,Y and Z axis 2 weeks before radiotherapy in group A were less than those in group B(P＜0.05).The others were no significant differences.According to the comparative analysis of the setup errors of head and neck tumors at different time points of radiotherapy,the setup errors of X-axis radiotherapy at 4 weeks were significantly higher than that before radiotherapy(P＜0.05).There were significant differences in Y-axis between before radiotherapy and 4 weeks of ra-diotherapy,2 weeks and 4 weeks of radiotherapy(P＜0.05),and the setup errors of radiotherapy increased with time.Conclusion For different malignant tumors,the setup errors of thermoplastic individual body pad combined with phantom and frame fixation are smaller and has better therapeutic accuracy.For head and neck malignant tumors,the setup error of 4 weeks of radiotherapy is si-gnificantly larger than that before radiotherapy.If conditions permit,it is recommended to relocate and make radiotherapy plans.
Postural fixation techniqueRadiotherapySetup errorsIndividualized body pad
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