论文部分内容阅读
目的比较鼻咽癌采用常规放疗和适形调强放疗在照射靶区和正常组织及危及器官的剂量分布差异。方法选择52例初次治疗的鼻咽癌患者为研究对象,调强组:CT(增强)扫描后融合MRI(增强)图像,勾画出原发肿瘤区(GTVnx)、PGTVnx(GTVnx+外放5mm)、CTV(PGTVnx+周围高危区域)、PCTV(CTV+外放3mm)等靶区和脑干、脊髓等重要的危及器官,自动多叶准直器(MLC)进行适形调强放疗。常规组:面颈联合野逐步缩野技术,GTV的处方剂量为DT 70Gy/35次,CTV的剂量要求为DT60Gy/30次。勾画出个体化挡铅的轮廓后,低熔点铅制作人工铅挡进行常规放疗。两组分别在治疗计划系统上计算各靶区的剂量分布及生物等效剂量(EUD)并进行比较。结果两种放疗方法在肿瘤PGTVnx、PCTV靶区平均剂量和生物等效剂量比较差异均无统计学意义(P>0.05);在危及器官的保护方面,两种放疗方法的脑干和脊髓的平均剂量、最高剂量与EUD值相近,差异无统计学意义(P>0.05)。结论 MLC适形调强放疗和人工铅挡常规放疗的肿瘤原发灶靶区和关键危及器官的剂量分布总体上无明显差异。实际应用中MLC适形调强放疗代替人工铅挡常规放疗进行鼻咽癌放疗更简便可行。
Objective To compare the dose distribution of nasopharyngeal carcinoma with conventional radiotherapy and conformal IMRT in the irradiated target area, normal tissues and organs at risk. Methods Fifty-two patients with nasopharyngeal carcinoma (NPC) treated initially were selected as study subjects. The intensity-modulated group (CT) images were fused with CT images and GTVnx, PGTVnx (GTVnx + exo 5 mm) CTV (PGTVnx + high-risk areas around), PCTV (CTV + external 3mm) and other target organs and brain stem, spinal cord and other important organs, automatic multilobar collimator (MLC) for IMRT. Routine group: facial and neck joint wild step shrinking technology, GTV prescription dose of DT 70Gy / 35 times, CTV dose requirement of DT60Gy / 30 times. After delineating the profile of individualized block lead, artificial lead block made of low melting point lead is used for conventional radiotherapy. The two groups calculated the dose distribution and the bioequivalent dose (EUD) of each target area on the treatment planning system and compared them. Results There was no significant difference in the mean dose and bioequivalent dose of PGTVnx and PCTV between the two radiotherapy methods (P> 0.05). In the aspect of organ protection, the mean of both brain stem and spinal cord The dose and the highest dose were similar to those of EUD, with no significant difference (P> 0.05). Conclusion There is no significant difference in the dose distribution of tumor-targeted target organs and key organs at risk in MLC conformal intensity-modulated radiotherapy and routine lead radiotherapy. Practical application of MLC conformal intensity modulated radiotherapy instead of manual lead block conventional radiotherapy of nasopharyngeal carcinoma radiation more simple and feasible.