Almén A, Ahlgren L, Mattsson S
Department of Radiation Physics Malmö, University of Lund, Sweden.
Phys Med Biol. 1991 Jun;36(6):815-22. doi: 10.1088/0031-9155/36/6/009.
Absorbed dose to the trunk and to the hands of technicians working with accelerators for radiotherapy have been measured with TL dosimeters for seven different accelerators. The contribution from induced activity in the accelerator and from radiation transmitted through the walls of the treatment room have been estimated separately. The total annual absorbed dose to the trunk and to the hands have been estimated to be 2 mGy, of which the induced activity contributes one-third (0.7 mGy). The exposure of the technicians was found to be dominated by radiation penetrating the walls of the treatment room. For one accelerator the absorbed dose rate in the treatment room was measured continuously between 0.5 min and 48 h after end of treatment. Immediately after irradiation with high-energy photons the radiation is dominated by 28Al and 62Cu T1/2 = 2.3 and 9.7 min respectively) and later by radionuclides with longer half-lives, 187W and 57Ni (T1/2 = 24 and 36 h respectively). Due to these radionuclides the radioactivity in the accelerator will build up and the technicians will therefore be irradiated every time they enter the treatment room and not only directly after a treatment with high-energy photons.
使用热释光剂量计测量了七台不同加速器的放疗技术人员躯干和手部的吸收剂量。分别估算了加速器中感生放射性以及穿过治疗室墙壁的辐射的贡献。躯干和手部的年总吸收剂量估计为2毫戈瑞，其中感生放射性贡献三分之一（0.7毫戈瑞）。发现技术人员的照射主要来自穿透治疗室墙壁的辐射。对于一台加速器，在治疗结束后0.5分钟至48小时内连续测量了治疗室内的吸收剂量率。在用高能光子照射后，辐射立即以28Al和62Cu为主（半衰期分别为2.3分钟和9.7分钟），随后以半衰期更长的放射性核素187W和57Ni为主（半衰期分别为24小时和36小时）。由于这些放射性核素，加速器中的放射性会积累，因此技术人员每次进入治疗室都会受到照射，而不仅仅是在高能光子治疗后直接受到照射。
