质子加速器治疗系统感生放射性辐射剂量研究
发布时间：2018-07-14 22:09
【摘要】：研究背景：随着我国医疗保健水平的不断提高及质子治疗系统的不断完善和成本降低,将来会有更多的质子治疗系统投入临床使用,因此,开展质子加速器治疗系统感生放射性的研究,对于保护放射工作人员的健康,保障质子治疗工作的顺利进行是很有必要的,通过此项研究也可为制订质子加速器治疗系统和感生放射性的职业卫生标准打下良好基础。 感生放射性是指当射束停止后,仍有“残留”辐射的现象,通常是中子活化的结果,较高能量的粒子加速器(大于10MeV)都可能通过(γ-n)、(p-n)等核反应产生泄漏或污染中子,进而产生感生放射性。感生放射性衰减较快,一般2-10分钟可减少一半或更多,如人员在停止出束后立即进入放射治疗室,可能受到感生放射性的照射。国际上对医用电子加速器产生的泄漏中子及感生放射性进行了较多的探讨,但是对质子加速器治疗系统的感生放射性研究尚未开展。 1991年,美国Loma Linda大学医学中心首先启用了医学专用质子装置,当前国际上关于质子治疗生物学效应及肿瘤治疗效果的研究方兴未艾。由于高能质子(230MeV以上)进入人体组织时,在一定深度可产生尖锐的博拉格峰(Bragg Peak),使能量集中于肿瘤部位,因此,质子治疗肿瘤技术已成为世界各国优先发展的肿瘤治疗高新技术。国内质子加速器放射治疗起步较晚,直到2005年,才由淄博万杰集团引进了IBA公司230MeV的质子加速器治疗系统。自万杰质子加速器正式运营开始,本人就一直关注该项目的研究,在读MPH期间对研究内容进行了较为系统的整理分析。 研究结果表明,质子加速器治疗系统的感生放射性水平较高,当以质子能量221.79MeV运行5分钟后停机5分钟时,摆位人员处的感生放射性可达41μGy/h,而一般医用电子加速器以15MV X射线照射6.27分钟(剂量约为40Gy),相应位置只有1.12～1.38μGy/h。但是,这种状况只是在设备调试或维修时才会长时间出束,且没有病人或体模阻挡,能量在治疗床上完全损失,才导致此状况的产生。在正常治疗模式下,根据实际测量,质子加速器机头的感生放射性对工作人员产生的剂量小于10μGy/h,但是随着使用时间及工作负荷的增加,该设备的感生放射性有了较大的增长,对于工作人员的年剂量的贡献增大,但是由于工作人员的摆位技术的提高,防护意识的增加,人员年剂量增长并不明显。 通过本项研究表明,由于感生放射性的累积,其产生的放射线对于放射工作人员的影响将逐年提高,为控制该职业危害,应长期对该项目进行关注,加强放射工作人员的剂量监测,加强他们的放射防护意识,严格其工作制度,以减少因感生放射性对工作人员的健康危害。
[Abstract]:Background: with the continuous improvement of medical care and the continuous improvement and cost reduction of proton therapy system in China, more proton therapy systems will be put into clinical use in the future. The study of induced radioactivity in the proton accelerator therapy system is necessary to protect the health of radiation workers and ensure the smooth progress of proton therapy. This study can also lay a good foundation for the development of proton accelerator therapy system and occupational health standards of induced radioactivity. Induced radioactivity refers to the phenomenon of "residual" radiation when the beam stops, usually as a result of neutron activation. A higher energy particle accelerator (> 10MeV) may leak or pollute neutrons through nuclear reactions such as 纬 -n), (p-n. In turn, it produces sensory radioactivity. The decay of induced radioactivity is faster and can be reduced by half or more in 2-10 minutes. If the personnel enter the radiation treatment room immediately after stopping the beam out, they may be exposed to the radiation. The leakage neutrons and induced radioactivity produced by medical electron accelerators have been discussed in the world, but the study of induced radioactivity in the proton accelerator therapy system has not been carried out yet. The medical center of Loma Linda University first used the medical proton device. The current research on the biological effect of proton therapy and the effect of tumor therapy is in the ascendant in the world. When high energy protons (more than 230 MeV) enter human tissues, a sharp Bragg Peak can be produced at a certain depth, which makes energy concentrate on the tumor site. Proton therapy has become a high-tech cancer therapy technology in the world. The domestic proton accelerator radiotherapy started late, until 2005, Zibo Wanjie Group introduced the IBA 230 MeV proton accelerator therapy system. Since the official operation of Wanjie Proton Accelerator, I have been paying close attention to the research of this project. The results show that the level of induced radioactivity in the proton accelerator therapy system is high. When the proton energy of 221.79 MeV runs for 5 minutes and then stops for 5 minutes, The induced radioactivity of the pendulum can reach 41 渭 Gy / h, while the general medical electron accelerator irradiated with 15MV X ray for 6.27 minutes (dose about 40Gy), the corresponding position is only 1.12g 1.38 渭 Gy / h. However, it is only when the equipment is debugged or repaired that it is out of the beam for a long time, and there is no patient or phantom blocking, and the energy is completely lost in the treatment bed, which leads to the occurrence of this condition. In normal treatment mode, according to actual measurements, the dose of induced radioactivity in the proton accelerator head to the workers is less than 10 渭 Gy / h, but with the increase of service time and workload, the induced radioactivity of the equipment has increased greatly. The contribution of annual dose to the staff is increased, but the annual dose increase is not obvious due to the improvement of the placement technique and the increase of the awareness of protection. Through this study, it is shown that the effects of radiation on radiation workers will increase year by year because of the accumulation of inductive radioactivity. In order to control the occupational hazards, the project should be paid close attention to for a long time. Strengthen the dose monitoring of radiation workers, strengthen their awareness of radiation protection, strict their work system, in order to reduce the health hazards caused by induced radiation.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R144.1
[Abstract]:Background: with the continuous improvement of medical care and the continuous improvement and cost reduction of proton therapy system in China, more proton therapy systems will be put into clinical use in the future. The study of induced radioactivity in the proton accelerator therapy system is necessary to protect the health of radiation workers and ensure the smooth progress of proton therapy. This study can also lay a good foundation for the development of proton accelerator therapy system and occupational health standards of induced radioactivity. Induced radioactivity refers to the phenomenon of "residual" radiation when the beam stops, usually as a result of neutron activation. A higher energy particle accelerator (> 10MeV) may leak or pollute neutrons through nuclear reactions such as 纬 -n), (p-n. In turn, it produces sensory radioactivity. The decay of induced radioactivity is faster and can be reduced by half or more in 2-10 minutes. If the personnel enter the radiation treatment room immediately after stopping the beam out, they may be exposed to the radiation. The leakage neutrons and induced radioactivity produced by medical electron accelerators have been discussed in the world, but the study of induced radioactivity in the proton accelerator therapy system has not been carried out yet. The medical center of Loma Linda University first used the medical proton device. The current research on the biological effect of proton therapy and the effect of tumor therapy is in the ascendant in the world. When high energy protons (more than 230 MeV) enter human tissues, a sharp Bragg Peak can be produced at a certain depth, which makes energy concentrate on the tumor site. Proton therapy has become a high-tech cancer therapy technology in the world. The domestic proton accelerator radiotherapy started late, until 2005, Zibo Wanjie Group introduced the IBA 230 MeV proton accelerator therapy system. Since the official operation of Wanjie Proton Accelerator, I have been paying close attention to the research of this project. The results show that the level of induced radioactivity in the proton accelerator therapy system is high. When the proton energy of 221.79 MeV runs for 5 minutes and then stops for 5 minutes, The induced radioactivity of the pendulum can reach 41 渭 Gy / h, while the general medical electron accelerator irradiated with 15MV X ray for 6.27 minutes (dose about 40Gy), the corresponding position is only 1.12g 1.38 渭 Gy / h. However, it is only when the equipment is debugged or repaired that it is out of the beam for a long time, and there is no patient or phantom blocking, and the energy is completely lost in the treatment bed, which leads to the occurrence of this condition. In normal treatment mode, according to actual measurements, the dose of induced radioactivity in the proton accelerator head to the workers is less than 10 渭 Gy / h, but with the increase of service time and workload, the induced radioactivity of the equipment has increased greatly. The contribution of annual dose to the staff is increased, but the annual dose increase is not obvious due to the improvement of the placement technique and the increase of the awareness of protection. Through this study, it is shown that the effects of radiation on radiation workers will increase year by year because of the accumulation of inductive radioactivity. In order to control the occupational hazards, the project should be paid close attention to for a long time. Strengthen the dose monitoring of radiation workers, strengthen their awareness of radiation protection, strict their work system, in order to reduce the health hazards caused by induced radiation.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R144.1
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