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目的对比放射性~(125)I粒子植入与不同外放疗技术治疗颈椎转移瘤的靶区及危及器官剂量分布,为临床治疗方式选择提供依据。方法随机选取10例颈椎转移瘤患者,三维适形放射治疗(3D-CRT)计划为单前野加双侧斜后野,调强适形放射治疗(IMRT)为5野等分,选用2弧容积旋转调强放疗(VMAT)。将Oncentra治疗计划系统中的图像传输到粒子计划系统,制定近距离放疗(LDR)术前模拟计划。结果脊髓剂量相同时,LDR的D90和D95生物等效剂量(BED)分别为(184.15±25.84)Gy、(161.45±26.35)Gy。VMAT、IMRT、3D-CRT对应的靶区D95BED 2 Gy/f时分别为:(120.52±10.66)Gy、(119.19±10.91)Gy、(96.24±28.65)Gy;3 Gy/f时分别为:(122.19±7.54)Gy、(122.37±8.19)Gy、(95.94±24.70)Gy。靶区各参数与LDR相比,均服从正态分布,配对t检验差异具有统计学意义(P=0.00)。VMAT、IMRT与LDR比较,黏膜V5差异无统计学意义(P=0.16,0.34),只有3D-CRT高于LDR(P=0.00)。黏膜V30、DmeanLDR均低于3种外放疗技术(P=0.00)。其余甲状腺、腮腺、下颌骨各参数,LDR最低,差异具有统计学意义(P=0.00)。结论 3D-CRT、IMRT、VMAT单次2 Gy及3 Gy分割方案与LDR相比,脊髓剂量相同时,LDR的靶区剂量更高,同时有效地保护周围危及器官。对于放疗后复发的颈椎椎体转移瘤,LDR具有剂量学优势。
Objective To compare the dose distribution of radioactive 125 I seed implantation with different external radiotherapy techniques in the treatment of cervical metastases and to provide the basis for the selection of clinical treatment modalities. Methods Ten patients with metastatic cervical spondylosis were selected. The three-dimensional conformal radiotherapy (3D-CRT) was planned to be single anterior plus bilateral oblique posterior, and IMRT was divided into five equal fields. Two arc volumes Rotary IMRT (VMAT). The images in the Oncentra treatment planning system are transmitted to the particle planning system to develop a pre-DRR simulation plan. Results The equivalent dosages of D90 and D95 for LDR were (184.15 ± 25.84) Gy and (161.45 ± 26.35) Gy, respectively, at the same dose of spinal cord. The target area D95BED at VMAT, IMRT and 3D-CRT were (120.52 ± 10.66) Gy, (119.19 ± 10.91) Gy and (96.24 ± 28.65) Gy, respectively at 3 Gy / f 122.19 ± 7.54) Gy, (122.37 ± 8.19) Gy, (95.94 ± 24.70) Gy. The parameters of the target area compared with the LDR, are subject to normal distribution, paired t test was statistically significant difference (P = 0.00). VMAT, IMRT compared with LDR, V5 mucosal differences were not statistically significant (P = 0.16,0.34), only 3D-CRT was higher than LDR (P = 0.00). Mucosal V30, DmeanLDR were lower than the three external radiotherapy techniques (P = 0.00). The remaining thyroid, parotid and mandible parameters, LDR lowest, the difference was statistically significant (P = 0.00). Conclusions Compared with LDR, the 3D-CRT, IMRT and VMAT single 2 Gy and 3 Gy divisions have a higher target dose of LDR compared with LDR. For radiotherapy of cervical vertebral metastases, LDR has a dose-dependent advantage.