鼻咽癌放射治疗照射野最佳衔接方法的探讨

A mono-isocentric technique for nasopharygeal carcinoma and regional nodal therapy through dual asymmetric jaws with integral block

目的 探讨鼻咽癌患者放射治疗中面颈野或耳前野与颈切线野的最佳衔接方法。方法 用带独立准直器的直线加速器 ,以一个等中心、半束整体铅模照射面颈野或耳前野与颈切线野用于鼻咽癌患者的放射治疗。结果 根据测量 ,面颈野或耳前野与颈切线野之间的剂量分布满意、无冷点和热点 ,与初步临床观察相符。结论 用一个等中心并半束整体铅模放射治疗鼻咽癌患者时 ,面颈野或耳前野与颈切线野间的剂量衔接满意。

Objective To achieve a perfect transverse plane match between the portals for the primary tumor and the upper neck nodes and portals for middle lower neck and the supraclavicular nodes in patients with nasopharyngeal carcinoma. Methods Our linear accelerator has asymmetric jaws. Integral blocks are used to define the field borders and beam-split the facio-upper neck field and the tangential lower neck-supraclavicular field at the match plane, namely the upper border of the tangential field and the lower border of the facio-upper neck fields. Results Dosimetry showed that asymmetric jaws provided almost equivalent field edge definition and superior absorption in comparison with currobent block. The dose distribution at the junction of the neighboring portals conformed well to QA,without any 'hot spots' or 'cold spots'.Conclusion Our treatment technique takes full advantage of dual asymmetric jaws and integral block to achieve a perfect match-plane, and necessitates only one isocenter and set-up point.