Objective:To improve the quality assurance (QA) skills of radiotherapy personnel and medical students and reduce the radiation risk of training by developing a remote training system for QA of medical electronic linear accelerators.Methods:This training system was built based on radiotherapy technology and quality control contents of medical electronic linear accelerators, and a virtual reality interactive software was developed using extended reality (XR) technology Unity 3D. A remote control module of multi-terminal platform was also developed. A multi-perspective evaluation system was adopted and a questionnaire was designed to analyze the application value of this system.Results:The training system reproduced the live environment and physical objects of medical electronic linear accelerator treatment room. It built a multi-terminal virtual simulation training system with radiotherapy technology as well as QA knowledge system. This system could provide 5G remote control of medical electronic linear accelerator for off-site quality control demonstration and guidance. By March 1, 2022, a total number of 133 people had been trained using this system, 76 valid questionnaires had been taken, of which 90.79% (69/76) of the respondents trusted the experimental results shown by the system and 88.16% (67/76) of the respondents considered the training system necessary.Conclusions:The training effect of this system is widely recognized. It fundamentally reduces the training radiation hazard and provides reference for the reform and progress of QA training mode of medical electronic linear accelerators.

Objective:To explore the feasibility of recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology in the Cyberknife Synchrony-based respiratory tracking.Methods:CT scans of an inflatable pig lung after anti-rot processing were obtained. Then, eight simulated tumor lesion sites were designed in the left and right lung lobes using intelligent navigation software, with four classified as the sputum bronchial environment group and four classified as the wet bronchial environment group. Based on the implantation principle of Cyberknife fiducial markers, 32 recoverable fiducial markers were implanted around various simulated tumor lesions via bronchus under intelligent guidance. Then, the end-expiratory state of the pig lung was simulated, the pig lung was scanned again to obtain CT images of the implanted recoverable fiducial markers, and the number of successfully implanted fiducial markers was recorded. Eight deliverable Synchrony treatment protocols were designed using the Cyberknife planning system (Multiplan v4.6), and then the pig lung with simulated respiratory movements was exposed to radiation. After radiation, the implanted recoverable fiducial markers were retrieved using the bronchoscopy technique, and the number of successfully retrieved fiducial markers was recorded. Moreover, the translational errors, rotational errors, and rigid body errors were extracted from the Cyberknife log file and analyzed.Results:No recoverable fiducial markers slipped or fell during the experiment. Thirty-two recoverable fiducial markers were successfully implanted and recovered under the guidance of intelligent navigation bronchoscopy, with implantation and recovery success rates of both 100%. Moreover, the tracking rate and rigid body errors of the fiducial markers were 100% and less than 5 mm, respectively. The data from the Cyberknife log file indicated that there was no significant difference between the sputum bronchial environment group and the wet bronchial environment group in the translational errors in the left-right direction, the rotational errors in the roll direction, and the rotational errors in the pitch direction ( P>0.05). Compared to the wet bronchial environment group, the sputum bronchial environment group had slightly higher translational errors in front-back ( Z=-3.57, P<0.01) and cranio-caudal ( Z=-2.53, P<0.05) directions, lower rotational errors along the yaw axis ( Z = -3.88, P < 0.01), and lower rigid body error ( Z=-3.32, P<0.01), and the differences were all statistically significant. Conclusions:The recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology is feasible. Recoverable fiducial markers are stable in the bronchus of the phantom, and the Cyberknife tracking precision can meet clinical requirements. Therefore, the recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology has promising prospects in clinical and teaching applications.

目的 探讨射波刀治疗过程中幽闭恐惧症发作的成因与对策.方法 观察射波刀治疗的患者共373例,其中6例出现不同程度的幽闭恐惧症.对出现幽闭恐惧症者采取停止摆位措施,先解除诱因,继而进行认知行为疗法和放松训练为主的心理干预,同时运用音乐治疗技术进行干预.结果 6位患者均接受放射治疗师的综合应对措施,幽闭恐惧症程度逐渐减轻,最终均完成了全疗程的射波刀治疗.结论 射波刀治疗期间发生幽闭恐惧症,主要对策是解除患者的生理、心理诱因,通过合适的心理干预手段和音乐治疗技术缓解患者焦虑情绪,控制惊恐发作,使治疗顺利完成.

目的:本研究旨在探讨血浆EB病毒DNA(Epstein-Barr virus DNA EBV DNA)拷贝数在鼻咽癌转移患者化疗疗效监测方面的临床意义.方法:选取2006年12月至2007年6月在中山大学肿瘤防治中心确诊的16例鼻咽癌转移患者,均接受6个疗程化疗.化疗方案以PF为主,辅以TP方案.每2个疗程化疗后外周静脉采血并采用影像学检查评价疗效.血浆EBV DNA检测采用荧光定量PCR法.结果:化疗后,EBV DNA下降者,疗效评价与EBV DNA变化基本一致,一致率达80％以上；升高者,疗效评价与EBV DNA变化高度一致,一致率达100％.而EBV DNA始终为0者,或在治疗过程中降为0者,疗效评价与EBV DNA变化不一致.根据疗效分为PR、SD、PD三组,将化疗前后EBV DNA拷贝数的对数值进行分析,三组分别为-4.63±2.5、-2.25±2.3、3.23±0,三组比较有显著性差异(P=0.025).结论:血浆EBV DNA检测可作为评价鼻咽癌转移患者化疗疗效的一项血清学指标,与影像学联合应用可提高鼻咽癌疗效评价的准确性.

目的通过在乳腺癌患者体表放置铅点标记,解决电子摄影成像系统(EPID)的组织空间分辨率及影像清晰度质量较差造成的与数字重建射野(DRR)图像比较困难的实际问题。方法抽取就诊我院的女性乳腺癌切线野放射治疗患者10例,于原点0°与+90°/-90°位置预置体表铅点标记,分别摄取0°与+90°/-90°验证片与计算机断层显像模拟技术(CT-sim)重建所生成的DRR图像比较验证,求取所摄图像X、Y、Z轴实际摆位误差。结果 10例患者使用体外铅点标记法验证实际摆位,使用EPID所摄取的验证片图像与CT-sim重建所生成的DRR图像比较,取得X、Y、Z轴方向上摆位误差值,分别对X、Y、Z轴误差进行医学统计配对设计均数比较,所得X、Y、Z轴t值分别为2.836,3.564,2.910,P<0.05,两种方法比较结果所得差异具有统计学意义。结论使用体外铅点标记法对改进乳腺癌切线野摆位误差的图像验证具有实际意义。