鼻咽癌调强放疗技术临床应用初浅体会

Intensity Modulation Radiation Therapy for the Nasopharyngeal Carcinomas.

目的探讨用动态调强放疗技术对鼻咽癌在日常临床工作中的可行性。方法2000年3月～2004年2月共有25例鼻咽癌接受调强破疗，病人用PQSCT扫描，医师在CT模拟工作站上（AcQsim）勾画GTV，CTV颈部淋巴结。再将CT模拟工作站上勾画好的图像传至逆向治疗计划（Cadplan-Helios）。用放疗专用局域网Varis将做好治疗计划连接varian2100C／D带有80叶多叶准直器（MLC）的直线加速器，实施调强放疗。治疗前用体膜用Farmar剂量仪，Scanditronix半导体剂量仪510DPD以及Scanditronix胶片剂量仪分别对逆向治疗计划以及直线加速器和MLC进行质量验证。结果调强放疗的病人GTV平均刺量为72Gy。计划靶区体积平均剂量〉90％的处方剂量。治疗的野数一般用5～7个野。由于动态调强，5个放射野总共花费12～15min时间。位置验证射野中心误差为±3mm。MLC叶片验证误差在规定范围内。治疗计划剂量计算在体膜上做绝对剂量验证，结果〈2％剂量误差。急性放疗毒副反应在Ⅱ～Ⅲ级，均在正常组织耐受量范围内。病人口干情况用非参数统计。结论运用动态调强放射治疗技术和逆向治疗计划在临床日常放疗中活疗鼻咽癌是确实可行的。用调强放射治疗技术，病人有好的耐受性。比较常规的放射治疗技术，调强放射治疗技术显示更能减少肿瘤周固正常组织的削量同时能提高肿瘤靶区的荆量，提高了治疗增益比。

Objective It is intent to evaluate the nasopharyngeal caner in our clinical department. Methods dynamic technique of intensity modulated radiation therapy （IMRT） for the From the March 2000 to February 2004 there are twety-fivc patients who suffered from the nasopharyngeal carcinoma to performing intensity modulated radiation therapy （IMRT）. At first the PQS CT scan had been done for all patients. The doctor delineate GTV or PTV on CT scan slice step by step in CT simulation workstation （AcQsim） . Varis that is network play a role to connected from the AcQsim to the Cadplan-Ilelios and from the Cadplan-Helios to the Linac （Varian 2100C/D） with 80 pairs of multileaf collimator （MLC）. Befbre IMRT it had to do to verity, the Cadplan-llelios and the Linac with MLC .We have used a phantom With Farmar dosimeter and Scanditronix semiconductor dosimeter DPD510 and film dosimeter.Results The average dose of the GTV is 72 Gy. The average dose of the measurement for planning target volume is more than 90% prescribed dose. The 5 ～ 7 radiotherapy fields were delivered for most patients. Owing to dynamic technique of IMRT, We have just spent 12 ～ 15 minutes for delivering 5 radiotherapy fields. The center error lbr radiation position is ＋3mm. MLC verification guaranteed to do IMRT.The absolute dose verification in the phantom is〈2% dose error. According to RTOG, acute toxicity reaction were in grade Ⅱ～Ⅲ . Conclusion It is possibility to apply IMRT for the nasopharyngeal caner in the clinic. The patients who performed IMRT have had good tolerance. To compare conventional radiotherapy skill, IMRT have advantage that it can more reduce the dose in surrounding normal tissue and escalate dose in the target volume.