This paper gives a detailed description of a radiological accident of ^(192)Ir source occurring on May 7,2014 in Nanjing,China(the 5⋅7 accident),encompassing a combination of accident overview,emergency response,inves...This paper gives a detailed description of a radiological accident of ^(192)Ir source occurring on May 7,2014 in Nanjing,China(the 5⋅7 accident),encompassing a combination of accident overview,emergency response,investigation process and results,dose estimation,medical treatment,experience and lessons learnt.The investigation showed that the accident was mainly caused by insufficient attention to the radiation safety,non-compliance with licensing conditions and employment of untrained temporary radiographer without equipped with alarm dosimeters.Additionally,no area radiation survey meter was used to verify whether the source would have retracted to radiography camera after every exposure.It therefore is the important means to strengthen the management of radioactive source safety and put the strict management measures in place,implement the requirements for personnel qualification management,strengthen regulatory inspection and actively poster safety culture,which are necessary to avoid accidents.This paper aims to provide experience and reference for the emergency response and countermeasure of radiological accidents involving industrial radioactive sources.展开更多
高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,...高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,但针对原子高科股份有限公司生产的HDR ^(192)Ir源的国内研究较少。为了计算国产HDR ^(192)Ir源的剂量学参数,依据美国医学物理师协会(American Association of Physicists in Medicine,AAPM)TG43-U1推荐的剂量学参数计算方法,使用蒙特卡罗模拟软件建立^(192)Ir源的详细结构模型进行模拟计算。模拟结果显示:剂量率常数为1.105 cGy·h^(-1)·U^(-1),与文献值差异小于1.2%;单位活度空气比释动能率为9.788×10^(-8) U·Bq^(-1),差异为0.23%;径向剂量函数和各向异性函数结果与文献一致。结果表明,该模型对于国产HDR ^(192)Ir源的临床应用,具有一定的指导意义。展开更多
The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-ra...The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment.展开更多
文摘This paper gives a detailed description of a radiological accident of ^(192)Ir source occurring on May 7,2014 in Nanjing,China(the 5⋅7 accident),encompassing a combination of accident overview,emergency response,investigation process and results,dose estimation,medical treatment,experience and lessons learnt.The investigation showed that the accident was mainly caused by insufficient attention to the radiation safety,non-compliance with licensing conditions and employment of untrained temporary radiographer without equipped with alarm dosimeters.Additionally,no area radiation survey meter was used to verify whether the source would have retracted to radiography camera after every exposure.It therefore is the important means to strengthen the management of radioactive source safety and put the strict management measures in place,implement the requirements for personnel qualification management,strengthen regulatory inspection and actively poster safety culture,which are necessary to avoid accidents.This paper aims to provide experience and reference for the emergency response and countermeasure of radiological accidents involving industrial radioactive sources.
文摘高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,但针对原子高科股份有限公司生产的HDR ^(192)Ir源的国内研究较少。为了计算国产HDR ^(192)Ir源的剂量学参数,依据美国医学物理师协会(American Association of Physicists in Medicine,AAPM)TG43-U1推荐的剂量学参数计算方法,使用蒙特卡罗模拟软件建立^(192)Ir源的详细结构模型进行模拟计算。模拟结果显示:剂量率常数为1.105 cGy·h^(-1)·U^(-1),与文献值差异小于1.2%;单位活度空气比释动能率为9.788×10^(-8) U·Bq^(-1),差异为0.23%;径向剂量函数和各向异性函数结果与文献一致。结果表明,该模型对于国产HDR ^(192)Ir源的临床应用,具有一定的指导意义。
文摘The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment.
