不同放疗计划对局限期颅内生殖细胞瘤患者正常脑组织的影响

Influence of different radiotherapy plans on the normal brain tissue in patients with localized intracranial germinoma

目的探讨全脑室调强放疗、三维适形放疗和两野对穿放疗对局限期颅内生殖细胞瘤患者正常脑组织的影响。方法颅内生殖细胞瘤患者21例,给予局部病灶20Gy/10~11F诊断性放疗,确诊颅内生殖细胞瘤后给予第2疗程放疗,分别制定全脑室调强放疗计划、全脑室三维适形放疗计划和全脑两野对穿放疗计划,推量至50~54Gy/25~29F。比较3种计划下覆盖99%、95%全脑室靶区、局部肿瘤靶区的最小剂量和10、20、30、40Gy剂量下正常脑组织的辐射体积。结果 3种放疗计划覆盖99%、95%全脑室靶区、局部肿瘤靶区的最小剂量比较差异无统计学意义（P〉0.05）;10、20、30、40Gy剂量下,全脑室调强放疗时正常脑组织的辐射体积（71.63%、55.07%、29.45%、6.98%）低于全脑室三维适形放疗计划（82.32%、64.22%、44.85%、12.69%）和全脑两野对穿放疗（100.00%、100.00%、94.18%、32.52%）（P〈0.01）。结论全脑室调强放疗用于颅内局限期生殖细胞瘤治疗可减少正常脑组织所受的高剂量辐射。

Objective To evaluate the influence of intensity-modulated radiotherapy（IMRT）,three-dimensional conformal radiotherapy（3D-CRT）and whole-brain parallel opposed fields irradiation（WBI）on the normal brain tissue in patients with localized intracranial germinoma.Methods Twenty-one patients with localized primary intracranial germinomas diagnosed by radiotherapy at a radiation dose of 20Gy/10~11Freceived the second course of radiotherapy at the dose of 50~54Gy/25~29F.Similar treatment plans were produced by use of IMRT,3D-CRT and WBI to compare the minimum dose covering 99%and 95% whole-ventricular irradiation（WVI）and planning target volume（PTV）,and cerebral hemisphere sparing at the doses of 10,20,30 and 40Gy.Results There were no significant differences in the minimum dose covering 99% and 95% WVI and PTV among three plans（P〉0.05）.The mean irradiated cerebral hemisphere volumes were significantly lower in IMRT plan（71.63%,55.07%,29.45%,6.98%）than those in 3D-CRT plan（82.32%,64.22%,44.85%,12.69%）and WBI plan（100.00%,100.00%,94.18%,32.52%）at the doses of10,20,30 and 40Gy（P〈0.01）.Conclusion IMRT is the most conformal technique in the treatment of localized primary intracranial germinoma which offers significant sparing of normal brain from high-dose irradiation.