γ累积剂量对闪烁凝胶剂量响应影响研究

Effect of γ Cumulative Dose on Dose Response of Scintillation Gel

针对基于闪烁凝胶的放疗剂量验证装置中γ累积剂量对闪烁凝胶剂量响应的影响,使用60Co放射源对多个凝胶样品分别照射不同时长,利用光电倍增管和放疗平台对各样品进行测试,对比凝胶的发光效率和对剂量的响应.结果表明,γ累积剂量在1000 Gy以下时凝胶对剂量的响应呈线性,且发光效率基本保持不变,而累积剂量在1000~2000 Gy时凝胶发光效率明显下降,但对剂量的响应仍呈线性.

In order to study the effect ofγcumulative dose on the dose response of scintillation gel in radiotherapy dose verification device based on scintillating gel.Firstly,gel samples were irradiated at different times by using~(60)Co.Then,the samples were tested by photomultiplier tube and radiotherapy machine.Finally,the luminous efficiency and the dose response of the gel were compared.The experimental results showed that the gel dose response was linear and the luminous efficiency basically remained unchanged under the cumulative dose of 1000 Gy.When the cumulative dose was 1000~2000 Gy,the luminous efficiency of the gel decreased significantly,but the response to the dose was still linear.The results can effectively guide the use period of gel samples in radiotherapy dose verification device based on scintillation gel.And it is of great significance to avoid inaccurate dose verification due to the gel degeneration caused by higherγcumulative dose in practical work.