鼻咽癌调强和常规放疗计划的剂量学对比

Dosimetric comparison with conventional radiation therapy and intensity modulated radiation therapy to nasopharyngeal carcinoma

目的利用三维治疗计划系统(3DTPS)对鼻咽癌常规放疗(CRT)和逆向调强放疗(IMRT)计划作剂量学比较,评估不同照射方法的优缺点。方法选择12例病理证实的鼻咽癌患者,用3DTPS对每例患者分别作出CRT和IMRT计划。根据靶区V95%、D5%、D95%、D5%/D95%、靶区最大值、最小值及平均值和正常组织受量(D50,D33,D5、Dm ax和Dm ean等)来比较这两种计划剂量学的差异。结果两种不同计划中的靶区分布,GTVnx、GTVnd和CTV1差别不大,但对于亚临床区CTV2和某些正常组织有显著性差异。结论对鼻咽癌原发灶和转移淋巴结,CRT和IMRT计划均有较好覆盖。但在亚临床病灶方面,IMRT比CRT包含靶区更好一些,且IMRT减少了腮腺、颞叶、垂体和颞颌关节等正常组织的照射剂量。

Objective To compare the difference between conventional radiation therapy （CRT） and intensity modulated radiation therapy （IMRT） to nasopharyngeal carcinoma （NPC） patients by 3 dimensional treatment planning system （3DTPS）. Methods Twelve NPC patients＇ treatment plans were designed as IMRT and CRT according to 3DTPS, respectively. The following values were measured, such as V95%,D5%,D95%,D5%/D95% , Dmin, Dmax and Dmean of the target volume, and the D50 ,D33 ,D5 , Dmax and Dmean of normal tissues. Results The dose coverage rate of PGTVnx, PGTVnd and PCTV1 in the IMRT plan were compared to CRT with no statistical difference. However, there was obvious difference in PCTV2 and some normal tissues. Conclusion Both IMRT and CRT have good coverage to primary tumor and metastatic lymph nodes. IMRT can spare the temporomandibular joint, parotid, temporal lobe and pituitary from high dose irradiation.