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目的通过测量钴-60治疗机在射野内的输出剂量率及其分布,获得当前剂量率的大小,并分析剂量分布的均匀性包括射野平坦度和对称性,以此来指导临床肿瘤放射治疗和放射医学实验。方法用指形电离室剂量计在源皮距80 cm处对20 cm×20 cm射野Cross-Plane和In-Plane方向取点测量,通过数据分析来评估钴-60治疗机的剂量率和射野内剂量的均匀性。结果得到5个方形野内当前的平均剂量率,可提供给使用者作为参考数据。钴-60治疗机的平坦度与对称性标准要求偏差±3%以内,分析结果基本符合。结论该钴-60治疗机的射野剂量分布较均匀,对肿瘤治疗或者放射医学实验的影响较小。
OBJECTIVE: To measure the output dose rate and its distribution in the field of Cobalt-60 treatment machine to obtain the current dose rate, and to analyze the uniformity of dose distribution including flatness and symmetry of the field to guide clinical tumor radiotherapy And radiology experiments. Methods A finger ionization chamber dosimeter was used to take measurements of the Cross-Plane and In-Plane directions of 20 cm × 20 cm at the source skin distance of 80 cm. The data rates were used to evaluate the dose rate and radiation of the cobalt-60 treatment machine Intra-field dose uniformity. The results obtained in the current five square field average dose rate can be provided to the user as a reference data. Cobalt-60 treatment machine flatness and symmetry standards deviation within ± 3%, the analysis results are basically consistent. Conclusion The dose distribution of the Cobalt-60 treatment machine is more uniform, and it has less effect on tumor treatment or radiation medicine experiment.