X射线生物辐照仪剂量学探讨

目的 探讨X射线生物辐照仪的射野剂量和周围环境辐射剂量。方法 用PTW UNIDOS电离室剂量仪测量X射线生物辐照仪正常工作状态时有效射野80%范围内的多对对称点的剂量,测量射野中心点剂量且每周重复测量一次;用451P环境剂量巡测仪测量X射线生物辐照仪正常工作状态和停机状态时前面、后面、左边、右边和顶部各方向的周围环境辐射剂量。结果 X射线生物辐照仪剂量输出连续7周测量稳定性< 1%,射野对称性为2%,射野平坦度为9.8%;X射线生物辐照仪正常工作状态的周围环境辐射剂量均值为0.194 μSv,属于本底辐射,最大值为辐照仪前面的0.308 μSv略高于且接近本底辐射最高标准。结论 X射线生物辐照仪正常工作状态时射野剂量输出稳定,射野对称性较好,射野平坦度存在瑕疵;环境辐射剂量除前面接近本底辐射最高标准,其余均属于本底辐射,建议操作者在X射线生物辐照仪出束时,远离辐照仪,尽可能减少接受辐射。

Investigation of the Radiation Dosiology in a X-ray Biologic Irradiator

Objective To investigate the field dosage and the environmental radiation dose of the X-ray biologic irradiator.Methods To measure the doses of the multiple-twin points in the 80 percent area of the effective field of the X-ray biologic irradiator,and to measure the dose of the central point of the field and repeat once a week,when the X-ray biologic irradiator was working,by using PTW UNIDOS ionization chamber dosimeter. To measure the environmental radiation doses of the front,the back,the left,the right and the top of the X-ray biologic irradiator,by using 451p model dosemeter,when the X-ray biologic irradiator was working.Results The results showed that the export stability of the field was less than 1%,the dose symmetry of the field equal or less than 2%,the platness of the field was 9.8%,when the X-ray biologic irradiator was working.The environmental radiation dose of the X-ray biologic irradiator,when it was working,averaged 0.194 μSv,which remained with the background radiation.The maximum value of the doses was 0.308 μSv that was the dose of the front,which was slight higher and approached the highest standard of the background radiation.Conclusion The dose exported steadily in the X-ray biologic irradiator.The dose symmetry of the field of the X-ray biologic irradiator was fine,and the flatness of the field had flaw.The environmental radiation dose of the front of the X-ray biologic irradiator was slighty higher and approached the highest standard of the background radiation.The environmental radiation doses of the other parts of the X-ray biologic irradiator remained with the background radiation.The operator is suggested to stay away from the X-ray biologic irradiator for less radiation dose,when the X-ray biologic irradiator is working.