質子加速器治療系統(tǒng)感生放射性輻射劑量研究
發(fā)布時間：2018-07-14 22:09
【摘要】：研究背景：隨著我國醫(yī)療保健水平的不斷提高及質子治療系統(tǒng)的不斷完善和成本降低,將來會有更多的質子治療系統(tǒng)投入臨床使用,因此,開展質子加速器治療系統(tǒng)感生放射性的研究,對于保護放射工作人員的健康,保障質子治療工作的順利進行是很有必要的,通過此項研究也可為制訂質子加速器治療系統(tǒng)和感生放射性的職業(yè)衛(wèi)生標準打下良好基礎。 感生放射性是指當射束停止后,仍有“殘留”輻射的現(xiàn)象,通常是中子活化的結果,較高能量的粒子加速器(大于10MeV)都可能通過(γ-n)、(p-n)等核反應產(chǎn)生泄漏或污染中子,進而產(chǎn)生感生放射性。感生放射性衰減較快,一般2-10分鐘可減少一半或更多,如人員在停止出束后立即進入放射治療室,可能受到感生放射性的照射。國際上對醫(yī)用電子加速器產(chǎn)生的泄漏中子及感生放射性進行了較多的探討,但是對質子加速器治療系統(tǒng)的感生放射性研究尚未開展。 1991年,美國Loma Linda大學醫(yī)學中心首先啟用了醫(yī)學專用質子裝置,當前國際上關于質子治療生物學效應及腫瘤治療效果的研究方興未艾。由于高能質子(230MeV以上)進入人體組織時,在一定深度可產(chǎn)生尖銳的博拉格峰(Bragg Peak),使能量集中于腫瘤部位,因此,質子治療腫瘤技術已成為世界各國優(yōu)先發(fā)展的腫瘤治療高新技術。國內質子加速器放射治療起步較晚,直到2005年,才由淄博萬杰集團引進了IBA公司230MeV的質子加速器治療系統(tǒng)。自萬杰質子加速器正式運營開始,本人就一直關注該項目的研究,在讀MPH期間對研究內容進行了較為系統(tǒng)的整理分析。 研究結果表明,質子加速器治療系統(tǒng)的感生放射性水平較高,當以質子能量221.79MeV運行5分鐘后停機5分鐘時,擺位人員處的感生放射性可達41μGy/h,而一般醫(yī)用電子加速器以15MV X射線照射6.27分鐘(劑量約為40Gy),相應位置只有1.12～1.38μGy/h。但是,這種狀況只是在設備調試或維修時才會長時間出束,且沒有病人或體模阻擋,能量在治療床上完全損失,才導致此狀況的產(chǎn)生。在正常治療模式下,根據(jù)實際測量,質子加速器機頭的感生放射性對工作人員產(chǎn)生的劑量小于10μGy/h,但是隨著使用時間及工作負荷的增加,該設備的感生放射性有了較大的增長,對于工作人員的年劑量的貢獻增大,但是由于工作人員的擺位技術的提高,防護意識的增加,人員年劑量增長并不明顯。 通過本項研究表明,由于感生放射性的累積,其產(chǎn)生的放射線對于放射工作人員的影響將逐年提高,為控制該職業(yè)危害,應長期對該項目進行關注,加強放射工作人員的劑量監(jiān)測,加強他們的放射防護意識,嚴格其工作制度,以減少因感生放射性對工作人員的健康危害。
[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 緯 -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.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：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 緯 -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.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：R144.1
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