Dosimetric effects of isocenter on intensity-modulated radiotherapy for MR-Linac / 中华放射医学与防护杂志

Objective:To analyze the dosimetric effects on off-center tumour treatment plan resulting from the MR-Linac-based isocenter position radiotherapy plan.Methods:The cases of 19 patients who were treated in Sun Yat-sen University Cancer Center in 2020 were collected in this study. Two different IMRT plans were designed for each patient with off-center tumor both for group A with planned isocenter position as IMRT and group B with planed target center position as geometric center. The conformity index and homogeneity index of target, the dose normal tissue and the number of MU were compared between two plans.Results:The two IMRT plans met clinical dosimetric requirements. No statistical differences were found both in homogeneity index and conformity index ( P>0.05). Also there was no differences found in doses to normal tissues. However, the MU number (1 149±903, t=2.804, P=0.012) in group A was higher than that in group B (970±652). Conclusions:It is feasible to perform MR-Linac-based off-center treatment plan.

Two-Dimensional Electron Beam Radiotherapy Planning System with Modeling Function / 中国医疗器械杂志

In order to adapt to different target shapes and protect the surrounding normal tissues, the design of two-dimensional electron beam radiotherapy planning requires additional lead blocks. But the Pinnacle treatment planning system can not directly shape the lead block conformity to the size of the beam field given by the doctor. Every time, physicists need to manually drag the lead block to form the required beam field. When meeting a two-dimensional electron beam treatment planning with the same field parameters as before, physicists need to rearrange the field for dose calculation, which greatly reduces the design efficiency of the two-dimensional electron beam treatment planning. In this study, we independently developed a two-dimensional electron beam radiotherapy planning system based on Qt Creator. The system can quickly design a two-dimensional electron beam radiotherapy plan, which reduces the repeated work of physicists.

The demand analysis and plan design for the maintenance management system of medical equipment / 中国医学装备

Objective:To analyze the demands of maintenance management system of medical equipment, and realize the scientization and normalization of plan design for maintenance management system of medical equipment.Methods: On the basis of current status of maintenance management system of medical equipment, the demands of various department during management process were analyzed, and then a systematic maintenance management plan was designed to face to all of medical equipment in hospital.Results: The preponderances of this system were discussed from three aspects: equipment maintenance, equipment archive and equipment benefit.Conclusion: The application of this system can accelerate the progress of maintenance for medical equipment, enhance maintenance awareness of clinical medical staffs for medical equipment, improve the transparency of equipment scrapping and disposal, and provide effective references for demonstration and purchase of medical equipment.

Discussion of Three-dimensional Conformal Radiotherapy Plan for Pancreatic Cancer / 医疗卫生装备

Objective To discuss the three-dimensional conformal radiotherapy(3D-CRT) plan for pancreatic tumors.Methods The 3D-CRT plan of 30 cases of primary pancreatic cancer were designed according to the request of the doctors for PTV and the restricted receiving dose of the peripheral normal sensitive organs.The best plan was chosen referring the dose-volume histogram.Results By using ICRU dose reference point(the central point of target)as theunitary dose,95% dose line could be surrounded above 95% of the PTV.Conclusion The focus in different localization can be treated with different design in treating the pancreatic tumors.The reaction to radiotherapy is directly influenced by the volume and dosage of radiation to the normal hepatic tissues.