Preliminary research on dosimetry methods of 252Cf neutron after-loading radiotherapy machine / 中国医学装备

Objective:To study the dose measurements methods of neutron andγ-ray for 252Cf neutron after-load radiotherapy machine. Methods:To measure the neutron-γmixed field with one ion chamber that have the similar sensitivities of neutron andγ-ray, another ion chamber that only have sensitivities for γ-ray, little sensitivity for neutron. Verification measurement results with calculated values. Results:Calculate key parameters, measure neutron andγ-ray dose rate at the position of 2.5cm, 5cm, 7.5cm and 10cm from the 252Cf, the Maximum deviation is-5.22%compared with calculated values. Conclusion:The method of twin ion chamber can measure the neutron andγ-ray mixed field dose.