调强放疗对36例鼻咽癌患者腮腺功能的保护作用

目的 探讨调强适形放疗对鼻咽癌患者腮腺功能的保护作用。方法采用均衡配对方法将36例鼻咽癌患者分为调强放疗组(调强组)和常规放疗组(常规组),每组18例。调强组计划靶体积(pGTVnx) 72.0 Gy,常规组放疗2.0Gy/次,5次/周,共70.0Gy。于放疗前、放疗结束时及放疗后3及6个月、1及2年进行腮腺动态显像检测,计算腮腺的放射性摄取指数(UI)及酸性刺激后的分泌指数(EI)。并利用剂量体积直方图对腮腺组织进行受量分析。结果调强组和常规组的患者在放疗结束时、2年后腮腺的UI分别是77.6％、96.2％和56.8％、7.0％,EI分别是64.1％、95.3%和19.4％、0。调强组和常规组患者的健侧和患侧腮腺受照射的平均剂量分别为20.0、31.0Gy和61.0、68.2Gy。结论调强放疗可以明显减少腮腺受照剂量,有效保护腮腺功能。

Function protection of the parotid gland after intensity modulated radiotherapy for thirty-six patients of nasopharyngeal carcinoma

Objective To study the parotid gland function protection of intensity modulated radiotherapy (IMRT) for patients with nasopharyngeal carcinoma (NPC) Methods Thirty-six NPC patients were divided into IMRT group (therapy group) and conventional fraction (CF) group (control group) by random balanced design. Each group had 18 patients. The planning gross tumor volume (pGTV) of nasopharyngeal was treated with a total dose of 72.0 in therapy group, with a total dose of 70.0 Gy in control group(with daily 2.0 Gy/fraction and 5 times/week). Before treatment and at 3,6, and 9 months,1 and 2 years after therapy, all patients performed parotid imaging and both uptake index (UI) and excretion index (EI) after acid stimulation were calculated. The dose-volume histogram (DVH) was used to analyse the dose of parotid.Results The values of UI were 77.6% and 96.2% at the end of therapy and after tow years in therapy group and 56.8% and 7.0% in contrast group. The values of EI were 64.1% and 95.3% at the end of therapy and after tow years in therapy group and 19.4% and 0 in control group. The mean doses of normal side and the trouble side of parotid gland were 20.0 Gy and 31.0 Gy in therapy group and 61.0 Gy and 68.2 Gy in control group.Conclusions IMRT can reduce radiation dose of parotid glands compared with CF distinctly and thus protect parotid function effectively.