CAJ | 학술논문

目的：比较早期乳腺癌保乳术后三维适形放疗（3DCRT）及简化逆向动态调强放疗（IMRT）剂量学特点。方法随机选择14例早期乳腺癌保乳术后患者（4例左侧乳腺癌），每例患者选用6 MV-X线分别设计3DCRT、IMRT计划，全乳腺50 Gy/25次。3DCRT组：采用切线野照射，瘤床区不加量；IMRT组：采用逆向动态调强技术，以2对类切线野为调强主野的入射方向，瘤床区同步加量10 Gy/25次。根据剂量体积直方图（DVH）进行适形度指数（CI）及不均匀度指数（HI）、危及器官受照射剂量及体积的评价。结果与3 DCRT计划比较，IMRT计划降低了患侧肺、左侧乳腺癌患者心脏的高剂量受照体积，提高了其低剂量受照体积，DVH叉点剂量分别为（25．16±9．11）Gy、（28．63±10．41）Gy；IMRT组和3DCRT组计划健侧乳腺的V10差异无统计学意义[（4．13±5．17）％∶（1．99±2．43）％，t＝2．11，P＞0．05]，IMRT计划D30、平均剂量均较3DCRT增高[（2．23±1．77）Gy ∶（1．20±0．46）Gy，t＝2．58，P＜0．05；（2．35±1．59）Gy ∶（1．54±0．88）Gy，t＝3．15，P＜0．01）]；2组计划的HI差异无统计学意义[（1．25±0．10）∶（1．23±0．11），t＝1．25，P＞0．05]，IMRT计划CI 高于3DCRT[（0．75±0．07）∶（0．62±0．09），t＝5．68，P＜0．0001]。结论早期乳腺癌保乳术后四野简化逆向动态 IMRT技术较3 DCRT技术的主要优势在于瘤床同步加量，同时可以降低患侧肺的高剂量受照射体积，明显改善计划靶区CI，但HI无显著改善。早期乳腺癌保乳术后四野简化逆向动态IMRT技术是一种简便、合理、可行的计划设计方法。
목적：비교조기유선암보유술후삼유괄형방료（3DCRT）급간화역향동태조강방료（IMRT）제량학특점。방법수궤선택14례조기유선암보유술후환자（4례좌측유선암），매례환자선용6 MV-X선분별설계3DCRT、IMRT계화，전유선50 Gy/25차。3DCRT조：채용절선야조사，류상구불가량；IMRT조：채용역향동태조강기술，이2대류절선야위조강주야적입사방향，류상구동보가량10 Gy/25차。근거제량체적직방도（DVH）진행괄형도지수（CI）급불균균도지수（HI）、위급기관수조사제량급체적적평개。결과여3 DCRT계화비교，IMRT계화강저료환측폐、좌측유선암환자심장적고제량수조체적，제고료기저제량수조체적，DVH차점제량분별위（25．16±9．11）Gy、（28．63±10．41）Gy；IMRT조화3DCRT조계화건측유선적V10차이무통계학의의[（4．13±5．17）％∶（1．99±2．43）％，t＝2．11，P＞0．05]，IMRT계화D30、평균제량균교3DCRT증고[（2．23±1．77）Gy ∶（1．20±0．46）Gy，t＝2．58，P＜0．05；（2．35±1．59）Gy ∶（1．54±0．88）Gy，t＝3．15，P＜0．01）]；2조계화적HI차이무통계학의의[（1．25±0．10）∶（1．23±0．11），t＝1．25，P＞0．05]，IMRT계화CI 고우3DCRT[（0．75±0．07）∶（0．62±0．09），t＝5．68，P＜0．0001]。결론조기유선암보유술후사야간화역향동태 IMRT기술교3 DCRT기술적주요우세재우류상동보가량，동시가이강저환측폐적고제량수조사체적，명현개선계화파구CI，단HI무현저개선。조기유선암보유술후사야간화역향동태IMRT기술시일충간편、합리、가행적계화설계방법。
Objective To compare the dosage characteristics between three-dimensional conformal radiotherapy (3DCRT)plan and simplified inverse dynamic intensity modulated radiotherapy (IMRT)in patients with early-stage breast cancer after breast-conserving surgery.Methods 3DCRT and IMRT treament plans were designed for 14 female patients with early-stage breast cancer after breast-conserving surgery,4 of whom were left breast cancer cases.A dose of 50 Gy in 25 fractions to the whole ipsilateral breast was delivered using 6 MV photons for 3DCRT or IMRT.For 3DCRT plans,tangential field irradiation was adopted.While for IMRT,reverse dynamic intensity modulated technology was done through two pairs of tangential-likely fields, and 10 Gy was boosted to the tumor bed concomitantly in 25 fractions.The conformity index (CI),heterogenei-ty index (HI),dose and volume of organs at risk were evaluated by dose volume histograms (DVH).Results Compared with 3DCRT plans for ipsilateral lung,the high dose volumes were reduced and the low dose volumes were increased in IMRT plans.The same phenomenon was also observed for the heart of the patient with left breast cancer.The crosspoint doses of 3DCRT DVH and IMRT DVH for lung or heart were (25.16 ±9.11) Gy,(28.63 ±10.41 )Gy respectively.There was no difference between the two plans in the V10 of contra-lateral breast [IMRT(4.13 ±5.17)%∶3DCRT(1.99 ±2.43)%,t=2.11,P>0.05],but the D30 and mean of IMRT plan were higher than that of 3DCRT [(2.23 ±1.77)Gy ∶(1.20 ±0.46)Gy,t=2.58,P<0.05;(2.35 ±1.59)Gy ∶(1.54 ±0.88)Gy,t=3.15,P<0.01].The difference in HI between the two plans was not observed [IMRT(1.25 ±0.10)∶3DCRT(1.23 ±0.11),t=1.25,P>0.05].While the CI of IMRT plans were improved compared with 3DCRT [(0.75 ±0.07)∶(0.62 ±0.09),t =5.68,P<0.000 1]. Conclusion Compared with 3DCRT plan in patients with early-stage breast cancer after breast-conserving surgery,the main advantages of four fields simplified inverse dynamic IMRT are concomitant tumor boosting, decreasing the high dose volumes of ipsilateral lung,and improving the CI of planning target volume at the same time,but the HI is not improved.The IMRT plan is a simple,rational and feasible design scheme.