摘要
目的探讨适形放疗在60Co放射治疗机上的应用及临床意义。方法应用剂量仪检测不同厚度的低熔点铅对60Coγ射线的穿透率。采用双曝光技术进行放射治疗射野片的拍摄,然后与模拟机的计划片进行比较分析。结果低熔点铅的厚度达到5.8 cm可使60Coγ射线的穿透率<5%;射野片上的铅丝和挡块轮廓的影像都较清晰,但射野内组织影像的分辨率和图像对比度逊于常规的模拟机摄片。仍可以从射野片上分辨出照射野内各组织的结构和位置,从而分析和判断实际照射野是否达到放射治疗计划的要求。结论适形放疗有利于提高治疗增益比。射野片的实时性不如电子射野影像系统,但其具有成本低廉、容易实施的特点,可成为放疗执行阶段中重要的质量控制手段。
Objective To investigate the application and clinical significance of conformal radiation therapy in Cobalt-60 radiotherapy unit. Methods The dosemeter was used to detect penetration rate of ^60Co γ-ray through low-melting-point alloy lead（LML） of various thickness. Double radiography technique was used to take a portfilm. Then, the portfilm was analyzed and com- pared with the simulator planning film. Results It demonstrated that ^60Co γ-ray penetrates 5.8- centimeter-thick low-melting-point alloy lead plate less than 5%. The images of both plumbum lines and block boundaries were distinct in the portfilm, but the resolution and contrast of the tissue structure image was inferior to the ordinary film from simulator. However, all different structures and positions could be identified in order to assess if the actual field coincided with the radiation planning. Conclusion Conformal radiation therapy can contribute to improve therapeutic gain ratio. Although the real-time property of the portfilm is inferior to the electronic portal image device （EPID）. The double radiography portfilm is feasible as an important quality control method in radiation therapy due to its low cost and easier performance.
出处
《江西医学院学报》
2007年第3期77-80,共4页
Acta Academiae Medicinae Jiangxi
关键词
^60Co放射治疗机
适形放疗
挡铅托架
照射野
放射摄影术
cobalt-60 radiotherapy unit
conformal radiotherapy
block carriage
irradiation field
radiophotography
