保乳术后放射治疗的剂量学研究

目的探讨保乳术后全乳切线野调强放射治疗（T-IMRT）的剂量学优势。方法选择7例乳癌保乳术后病人,利用治疗计划系统分别设计切线野三维适形放射治疗（T-CRT）计划和T-IMRT计划。处方剂量均为50 Gy/25次。用剂量体积及靶区剂量分布评估T-CRT与T-IMRT计划优劣。结果 T-CRT和T-IMRT放疗计划计划靶区（PTV）V95、V100、V105、V110分别为（99.54±4.28）%、（60.71±9.77）%、（11.85±1.83）%、（0.10±1.08）%和（95.13±7.52）%、（92.28±2.29）%（、33.57±3.72）%、（0.09±1.16）%,V95、V100和V105差异有显著意义（t=2.447~3.707,P〈0.05）;T-IMRT与T-CRT比较,心脏和患侧肺的指标均有统计学差异（t=2.232~3.645,P〈0.05）。结论对乳癌保乳术后的PTV虽然T-CRT和T-IMRT计划均有较好覆盖,但T-IMRT有效降低了心、肺等正常组织的照射剂量。

STUDY ON DOSIOLOGY OF RADIOTHERAPY IN PATIENTS AFTER BREAST-CONSERVING SURGERY

Objective To evaluate the dosimetric superiority of intensity modulated radiotherapy of tangent field（TIMRT） for breast cancer after breast-conserving surgery（BCS）. Methods A 3-dimensional treatment planning system was used to design conventional radiotherapy of tangent field（T-CRT） and T-IMRT plans for seven breast cancer patients after BCS,with the prescribed dosage of 50 Gy/25 F.T-CRT and T-IMRT were compared by evaluation of the dose volume and dose profile. ResultsThe V95,V100,V105,V110 of PTV for T-CRT were（99.54±4.28）%,（60.71±9.77）%,（11.85±1.83）%,and（0.10±1.08）%,and those for T-IMRT were（95.13±7.52）%,（92.28±2.29）%,（33.57±3.72）%,and（0.09±1.16）%,respectively.Statistical differences were observed in V95,V100 and V105（t=2.447-3.707,P0.05）,but not in V110（P0.05）.Both the heart and lung indices of T-CRT and T-IMRT showed statistical differences（t=2.322-3.645,P0.05）. Conclusion For PTV after BCS,both T-CRT and T-IMRT plans have a satisfactory coverage,but the latter effectively reduce the expose dose for normal tissue of the heart and lung.