摘要
目的探讨早期乳腺癌保乳术后全乳适形调强放射治疗（IMRT）的剂量学优势。方法选择10例接受保乳手术的Tis-2N0M0早期乳腺癌病例，其中左侧乳腺癌6例，右侧乳腺癌4例，应用三维治疗计划系统（3D—TPS）为每位患者设计两种全乳放射治疗计划，即切线野常规计划与IMRT计划，处方剂量均为50Gy／25次。用剂量体积直方冈（DVH）来比较两种计划中计划靶体积（PTV）、危及器官（OARS）的剂量学差异。结果靶区覆盖率在两种计划中相似，分别为97．83％、97．61％，与常规计划相比IMRT计划的PTV接受〈95％处方剂量与〉103％处方剂量的体积百分比之和（IHI）从25．42％减少到2．71％，PTV接受至少105％处方剂量照射的体积百分比（V105%）从25．79％减少到1．08％，IMRT计划改善IHI和减少V105%的平均值，在PTV较大的患者中更明显。左侧乳腺癌患者心脏的平均剂量（Dmean）从6．72Gy减少到4．95Gy、心脏接受30Gy照射的体积百分比（V30）从7．23％减少到1．04％。所有患者同侧肺的Dmean从9．19Gy减少到7．65Gy、至少接受20Gy照射的体积百分比（V20）从22．34％减少到20．18％。对侧乳腺Dmean从5．12Gy减少到3．52Gy，对侧肺Dmean从2．76Gy减少到1．79Gy。右侧患者肝脏Dmean从7．23Gy减少到1．04Gy。结论全乳IMRT的剂量学优势主要是在保证靶区覆盖率的前提下，显著改善了靶区剂量分布的均匀性，并在一定程度上降低OARS的受照剂量与容积，乳房体积大的病例可以通过IMRT获得更好的剂量学结果。
Objective To evaluate the dosimetrie benefits of intensity-modulated radiotherapy （IMRT） for early stage breast cancer after breast-conserving surgery. Methods Ten patients with stage Tis-2N0M0 breast cancer receiving breast-conserving surgery were selected for the study. Six cases were on the left, four were on the right. A dosimetric comparison of IMRT with conventional wedged tangential technique was performed on each patient using three dimensional treatment planning. The total prescribed dose for both plans was 50 Gy/25 fractions. Dose volume histograms （DVH） were used to compare the planning target volume （PTV） and organs at risks（OARS）. Results The PTV coverage in IMRT plan was similar to that of the conventional plan （97.83 % vs 97.61%）. A better dose uniformity throughout the whole breast was achieved by IMRT plan. The percentage of PTV receiving less than 95 % prescribed dose and more than 103 % prescribed dose （inhomogeneity index IHI）, decreased from 25.42 % to 2.71%： the percentage of PTV receiving more than 105 % prescribed dose （V105%） decreased from 25.79 % to 1.08 %. A better amelioration of IHI and reduction of V105% in IMRT plans were observed in the relatively large VIN subgroup. The Dmean and percentage of volume receiving more than 30 Gy （V30） of heart from 6.72 Gy to 4.95 Gy, and from 7.23 % to 1.04 %. the Dmean and percentage of volume receiving more than 20 Gy （V20） of ipsilateral from 9,19 Gy to 7.65 Gy, and from 22.34 % to 20.18 %; the Dmean of contralateral breast decreased from 5.12 Gy to 3.52 Gy; the Dmean of contralateral lung decreased from 2.76 Gy to 1.79 Gy; the Dmean of liver decreased from 7.23 Gy to 1.04 Gy for right side patients. Conclusion Forward planning IMRT based on a standard tangential beam arrangement significantly improves the dose homogeneity throughout the target volume of intact breast and reduces the dose to OARS, especially in patients with large breast volumes who might be proposed as candidates of IMRT for intact breast.
出处
《肿瘤研究与临床》
CAS
2010年第3期182-185,共4页
Cancer Research and Clinic
关键词
乳腺肿瘤
放射疗法
调强放射治疗
三维治疗计划系统
剂量体积直方图
乳房保留
Breast neoplasms
dimensional treatment planning
DVH
Radiotherapy
Intensity modulation radiation therapy
Three- Breast-conserving surgery
