低熔点铅挡块在常规和适形放疗应用中的质量保证

目的探讨低熔点铅挡块的应用、制作、验证及质量保证。方法综合分析本院6年来所制作的计12000余块常规铅挡块和适形铅挡块，对3000余块挡块进行验证，对不同类型挡块做出误差分析和评价。结果有95%以上的挡块经验证符合临床使用要求，取得了良好效果，提高了放疗水平和治疗效果。但由于制作过程中环节众多，约有5%的挡块需重新制作。结论低熔点铅挡块在临床上使用广泛，效果满意，但因技术水平、设备精度、材料差异等因素，有小部分挡块不符要求。良好的质保措施可使其发挥经济、方便、简洁的特点。

The quality assurance of low melting-point alloy lead in conventional radiotherapy and conformal therapy

Objective To discuss the appllcation,production, verification and quality assurance of low meltingpoint alloy lead （LML）in conventional and conformal radiotherapies. Methods More than 3000 alloy lead blocks used in the past 6 years were studied. Then the variances of all the types of the blocks were analysed and evaluated. Results More than 95% lead blocks could meet the requirement of clinical treatment. About 5% lead had to be reproduced because of so many steps in the producing procedures. Conclusion Low melting-point alloy lead is widely used in radiation treatment. Because of the variances of technique ,accuracy of the equipment and materials, a fraction of them is not qualified. The strict quality assurance is necessary.