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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0.194μSv,属于本底辐射,最大值为辐照仪前面的0.308μSv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。
Objective To investigate the radiation dose and ambient radiation dose of X-ray bioradiator. Methods The PTW UNIDOS ionization chamber dosimeter was used to measure the dose of multiple pairs of symmetrical points within 80% of the effective field when the X-ray bioradiator was in normal working condition. The dose of the center of the field was measured and repeated every week. Dosimeter measures the ambient radiation dose in front of, behind, on the left, right, and top of each X-ray bio-irradiator during normal operation and shutdown. Results The dose stability of X-ray bioradiator was less than 1% for 7 weeks, the field symmetry was 2%, and the flatness of field was 9.8%. The mean ambient radiation dose of X-ray bioradiator in normal working condition 0.194μSv, belonging to the background radiation, the maximum value of 0.308μSv in front of the irradiator slightly higher than and near the highest background radiation standards. Conclusions X-ray bioradiator output dose is stable under normal working conditions with good field symmetry and flaw in field flatness. The ambient radiation dose is near the highest background radiation level, the rest are background radiation, It is recommended that operators leave the irradiator as soon as the X-ray bioradiator is out of the beam, minimizing exposure to radiation.