保乳术后固定野动态调强与容积调强放疗的剂量学比较

目的 比较早期乳腺癌保乳术后固定野动态调强与容积调强放疗治疗靶区和危及器官的剂量学差异.方法 20例左侧乳腺癌患者(均女性,24～75岁)保乳术后接受放疗,在同一患者CT影像上分别进行2野共面动态调强和容积调强(RapidArc)两种治疗计划设计.在剂量-体积直方图中读取两种计划的靶区剂量分布参数,心脏、双侧肺及对侧乳腺受照剂量和体积,对各参数的均数进行比较;并比较两者平均机器跳数和平均治疗时间的差异.结果 RapidArc较IMRT计划CTV V95%增加了0.65%(t=5.16,P=0.001),V105%下降了10.96%(t=-2.05,P=0.055),V110%下降了1.48%(t=-1.33,P=0.197).RapidArc计划的适形指数(CI)和均匀性指数(HI)均优于IMRT治疗计划,分别为0.88±0.02 vs 0.74±0.03(t=18.54,P＜0.001),1.11±0.01 Vs 1.12±0.02(t=-2.44,P=0.025).两种计划中左肺V20和Dmax比较差异无统计学意义,但在RapidArc计划中V10、V5、Dmix、Dmean明显增高,V5增高了接近30%.心脏V30和Dmax在两计划中无明显差异,而RapidArc计划的V10增加了18%,V5增加50%.RapidArc计划的右乳V5和右肺V5较IMRT分别增加了9.33%(t=9.31,P＜0.001)和3.04%(t=5.64,P＜0.001).RapidArc和IMRT平均机器跳数分别是608和437 MU(t=10.86,P＜0.001),平均治疗时间111.3和103.6 s(t=3.57,P=0.002).结论 早期乳腺癌保乳术后全乳腺RapidAre放疗与2野动态调强放疗相比,能明显改善靶区剂量分布均匀性.对于危及器官,高剂量区两种治疗计划之间无明显差异,低剂量区RapidArc的照射范围明显增加.与2野动态调强相比,RapidArc放疗机器跳数增加,治疗时间延长.

Abstract：

Objective To compare the dosimetric difference between volumetric are modulation with RapidArc and fixed field dynamic IMRT for breast cancer radiotherapy after breast-conserving surgery.Methods Twenty patients with early left-sided breast cancer received radiotherapy after breast-conserving surgery.After target definition,treatment planning was performed by RapidAre and two fixed fields dynamic IMRT respectively on the same CT scan.The target dose distribution,homogeneity of the breast,and the irradiation dose and volume for the lungs,heart,and eontralateral breast were read in the dosevolume histogram (DVH) and compared between RapidAre and IMRT.The treatment delivery time and monitor units were also compared.Results In comparison with the IMRT planning,the homogeneity of clinical target volume (CTV) ,the volume proportion of 95% prescribed dose (V95%) was significantly higher by 0.65% in RapidAre (t =5.16,P = 0.001) ,and the V105% and V110% were lower by 10.96% and 1.48 % respectively,however,without statistical significance (t =-2.05 ,P =0.055 and t =-1.33 ,P =0.197).The conformal index of planning target volume (PTV) by the Rap~dAre planning was (0.88±0.02),significantly higher than that by the IMRT planning [(0.74±0.03),t = 18.54,P < 0.001].The homogeneity index (HI) of PTV by the RapidArc planning was 1.11±0.01,significantly lower than that by the IMRT planning (1.12±0.02,t =-2.44,P =0.02).There were no significant differences in the maximum dose (Dmax) and V20 for the ipsilateral lung between the RapidArc and IMRT planning,but the values of V10,V5 ,Dmin and Dmean by RapidArc planning were all significantly higher than those by the IMRT planning (all P < 0.01).The values of max dose and V30 for the heart were similar by both techniques,but the values of V10 and V5 by the RapidArc planning were significantly higher (by 18% and 50% ,respectively).The V5 of the contralateral breast and lung by the RapidArc planning were increased by 9.33% and 3.04% respectively compared to the IMRT planning.The mean MU of the RapidArc was 608 MU,significantly higher than that by the IMRT planning (437 MU,t = 10.86,P < 0.001).The treatment time by the RapidArc planning was 111.3 s,significantly longer than that by IMRT planning (103.6 s,t = 3.57,P = 0.002).Conclusions The RapidArc planning improves the dose distribution of CTV and homogeneity of PTV for breast cancer radiotherapy after breast-conserving surgery.However,it significantly enlarges the volume of normal tissues irradiated in low dose areas,prolongs the treatment delivery time,and increases the MU value in comparison with IMRT.     

双示踪剂用于PET-CT图像勾画胸段食管癌生物靶区的模拟计划剂量学 比较

目的 探讨氟脱氧胸苷(FLT)PET-CT用于食管癌放疗计划的可行性,并与氟脱氧葡萄糖(FDG)PET-CT图像勾画生物靶区的模拟计划的剂量学进行比较.方法 对22例胸段食管癌患者分别行FLT、FDG PET-CT,在Philips Pinnacle3治疗计划系统中分别基于FLT、FDG PET-CT的最佳阈值图像进行靶区(GTV、CTV、PTV)勾画,并制定两种模拟放疗计划.在射野方向相同、保证处方剂量线包绕95%靶体积前提下,比较两组计划的剂量体积直方图参数.结果 基于FLT PET-CT计划的GTV、CTV和PTV小于FDG PET-CT的,分别为29.03 cm3∶33.05 cm3(t=-2.62,P＜0.05)、244.22 cm3∶257.01 cm3(t=-3.53,P＜0.05)和351.29 cm3∶379.85 cm3(t=-4.01,P＜0.05);而适形指数和均匀指数均相似,分别为0.74∶0.72(t=0.89,P＞0.05)和1.09∶1.11(t=1.41,P＞0.05);全肺V20、心脏V40和脊髓最大剂量也相似(t=-1.60、-1.55,P＞0.05).FLT PET-CT计划的平均肺受量、双肺V5、V10、V30、V40和V50、平均心脏受量和心脏V30明显低于FDG PET-CT的(t=-5.442～-2.637,P＜0.05).结论 两种示踪剂的PET-CT计划中靶区均能满足剂量要求,但FLTPET-CT的模拟计划会给心脏和肺带来潜在受益.

Abstract：

Objective To investigate a feasibility of treatment planning in thoracic esophageal carcinoma with 3-deoxy-3-fluorothymidine (FLT) PET-CT and to compare with fluorodeoxyglucose (FDG) PET-CT based on dosimetric analysis.MethodsTwenty-two patients with esophageal squamous cell carcinoma detected by FLT and FDG PET-CT were enrolled.The gross tumor volumes ( GTV ),clinical target volume(CTV) and planning target volume ( PTV ) were delineated using treatment planning system of Philips Pinnacle3 based on the optimal threshold of FLT and FDG PET-CT respectively,and to make two groups simulation treatment planning.The parameters of dose-volume histograms in two groups planning were compared in the similar direction and ensuring prescribed dose line surround 95% target volume.Results The values of GTV,CTV and PTV in FLT PET-CT planning were less than those of FDG,that dose received by spinal cord in two planning were not significantly yet ( t = - 1.60,- 1.55,all P ＞ 0.05 ).While,the values in mean lung dose,V5,V10,V30,V40 and V50 of bilateral lung,mean heart dose,and V30 of heart in FLT PET-CT planning were significant lower than those of FDG( t = -5.442 - -2.637,all P ＜0.05).Conclusions Compared with FDG,FLT PET-CT based treatment planning brings potential benefits for lungs and heart.     

乳腺癌术后放疗3种治疗计划的剂量学研究

Objective To investigate the dosimetric characteristics of helical tomotherapy(HT),intensity-modulated radiation therapy(IMRT)and three.dimensional conformal radiation therapy(3D-CRT)for the post-operative breast cancer as well as their comparison in protecting the normal tissues.Methods The CT images of 10 postoperative patients with early stage breast cancer were transferRed into HT and IMRT and 3D- CRT planning system respectively after the target region and normal tissues were drawn out with the same doctor.Each prescribed dose for three kinds of plans was 50 Gy/25 fractions.Inrradiation doses and volume at heart and double lungs as well as conformity index(CI)and homogeneity index(HI)were evaluated.Results The PTV volume of prescribed target dose of 95% and 100%in HT, IMRT and 3D-CRT groups were 99.13%and 95.87%,97.80%and 94.05%,96.37%and 87.29%.respectively.The CI and HI in HT.IMRT and 3D-CRT groups were 0.80±0.10 and 1.09 ±0.03,0.65±0.07 and 1.14±0.02,0.40±0.08 and 1.17±0.04,respectively V5,V10 and V20 of the heart were the lowest at 3D-CRT than HT and lM RT.V5 of the diseased lung was the lowest at 3D-CRT compared to HT and IMRT.V5 and V10 of the healthy lung were the lowest at 3 D-CRT compared to other groups.Conclusions Compared with IMRT and 3D-CRT.HT technique in treating breast cancer had the best conformity index and homogeneity index as well as steeper dose gradient.Irradiated doses and volume at the heart was the lowest at 3D- CRT and the highest at IMRT.Irradiated doses and volume of the heart and healthy lung as well as the diseased lung were the lowest at 3D-CRT compared to HT and IMRT groups.     

乳腺癌术后放疗3种治疗计划的剂量学研究

Objective To investigate the dosimetric characteristics of helical tomotherapy(HT),intensity-modulated radiation therapy(IMRT)and three.dimensional conformal radiation therapy(3D-CRT)for the post-operative breast cancer as well as their comparison in protecting the normal tissues.Methods The CT images of 10 postoperative patients with early stage breast cancer were transferRed into HT and IMRT and 3D- CRT planning system respectively after the target region and normal tissues were drawn out with the same doctor.Each prescribed dose for three kinds of plans was 50 Gy/25 fractions.Inrradiation doses and volume at heart and double lungs as well as conformity index(CI)and homogeneity index(HI)were evaluated.Results The PTV volume of prescribed target dose of 95% and 100%in HT, IMRT and 3D-CRT groups were 99.13%and 95.87%,97.80%and 94.05%,96.37%and 87.29%.respectively.The CI and HI in HT.IMRT and 3D-CRT groups were 0.80±0.10 and 1.09 ±0.03,0.65±0.07 and 1.14±0.02,0.40±0.08 and 1.17±0.04,respectively V5,V10 and V20 of the heart were the lowest at 3D-CRT than HT and lM RT.V5 of the diseased lung was the lowest at 3D-CRT compared to HT and IMRT.V5 and V10 of the healthy lung were the lowest at 3 D-CRT compared to other groups.Conclusions Compared with IMRT and 3D-CRT.HT technique in treating breast cancer had the best conformity index and homogeneity index as well as steeper dose gradient.Irradiated doses and volume at the heart was the lowest at 3D- CRT and the highest at IMRT.Irradiated doses and volume of the heart and healthy lung as well as the diseased lung were the lowest at 3D-CRT compared to HT and IMRT groups.     

直肠癌术前放疗中三维适形放疗与调强适形放疗的剂量学比较分析

Objective To compare the dose distribution of the three-dimensional conformal radiotherapy(3D-CRT)and 5-field or 7-field intensity modulated radiation therapy(IMRT), and to explore the value of IMRT in preoperative radiotherapy for rectal cancer.Methods Ten rectal cancer patients treated with preoperative combination radiotherapy and chemotherapy were enrolled in this study. 3D-CRT plan and the 5.field or 7-field IMRT plans were performed for each patient.The conformal index (CI),heterogeneity index(HI)of the planning target volume(PTV)and the dose of normal organs of 3D-CRT plan(3D-CRTp)and the 5-field or 7-field IMRT plans(IMRT5fp or IMRT7fp)were analyzed with the dose-volume histogram.Results The CI values of PTV were 0.91,0.87 and 0.78 in IMRT7fpIMRT5fp and 3D- CRT but with IMRT7fp>IMRT5fp>3D-CRTp(t=-5.69、-8.91,P<0.01),respectively.The HI values of PrV were 1.09,1.08 and 1.05 in IMRT5fp,IMRT7fp and 3D- CRTp but with IMRT5fp >IMRT7fp>3D- CRTp(t=3.41、-6.89,P<0.01),respectively.The ratio of dose volume were 0.08,0.10 and 0.19(t=2.79、3.52,P<0.05)in IMRT7fp,IMRT5fp and 3D- CRTp on the small intestine V50,with 0.07,0.10 and 0.19(t=2.58、3.40,P<0.05)in IMRT7fp,IMRT5fp and 3D-CRTp on the bladder V50 and 0.01,0.01 and 0.05(t=3.00、3.17,P<0.01)in IMRT7fp,IMRT5fp and 3D- CRTp on the fomoral head V45.The ratio of dose volume were 0.31 and 0.38(t=3.91,P<0.01)in IMRT7fp and IMRT5fp on the bone marrow V50,with 0.07 and 0.10 in IMRT7fp and IMRT5fp on bladder V45.Conclusions IMRT plan is superior to 3 D- CRT plan in dose conformal degrees of PTV with preoperative radiotherapy of rectal cancer and can significantly protect the normal tissues.The 7-field IMRT plan might be the optimal plan for dose conformal degree and dose uniformity compared with 5-field IMRT.     

旋转调强与固定野逆向调强放疗在颅脑多发转移瘤中的剂量学比较研究

Objective To evaluate the performace of fixed field Intensity modulated radiation therapy (IMRT) and RapidArc in the radiotherapy for multiple intracranial metastases.Methods The clinical data of 10 patients with multiple intracranial metastases,8 male and 2 female,aged 65-73,were used to design 3 plans:fixed field IMRT,RapidArc with single Arc (RA1),and RapidArc with double Arc (Arc 2).Dose-volume-histogram analysis was used to compare dose results,monitor unit,and delivery time.Results All 3 plans met the clinical requirements.The best target conformity and homogeneity were observed in the RA2 plan (Z = -2.803,- 2.904,P ＜ 0.05) and there were no statistical differences between the IMRT plan and RA1 plan.The maximum doses to the lens,eyes,and brainstem of the two RapidArc plans were all significantly lower than those of the IMRT plan(Z = -2.803--2.191 ,P ＜0.05),and the maximum dose to the optic nerves of the RA2 plan was significantly lower than that of the IMRT plan (Z = -2.293,-2.701 ,P ＜0.05).Compared with the IMRT plan,the average monitor units of the RA1 and RA2 plans were reduced by 29% and 24%,respectively,and the delivery time of these plans were significantly shorter by 84% and 69%,respectively.Conclusions Compared to the IMRT plan,RapidArc plans with single or double Arcs show similar or better effects in the target dose distribution,reduction of irradiation doses on organs at risk and,moreover,significant decrease of the monitor units and delivery time.     

直肠癌术前放疗中三维适形放疗与调强适形放疗的剂量学比较分析

Objective To compare the dose distribution of the three-dimensional conformal radiotherapy(3D-CRT)and 5-field or 7-field intensity modulated radiation therapy(IMRT), and to explore the value of IMRT in preoperative radiotherapy for rectal cancer.Methods Ten rectal cancer patients treated with preoperative combination radiotherapy and chemotherapy were enrolled in this study. 3D-CRT plan and the 5.field or 7-field IMRT plans were performed for each patient.The conformal index (CI),heterogeneity index(HI)of the planning target volume(PTV)and the dose of normal organs of 3D-CRT plan(3D-CRTp)and the 5-field or 7-field IMRT plans(IMRT5fp or IMRT7fp)were analyzed with the dose-volume histogram.Results The CI values of PTV were 0.91,0.87 and 0.78 in IMRT7fpIMRT5fp and 3D- CRT but with IMRT7fp>IMRT5fp>3D-CRTp(t=-5.69、-8.91,P<0.01),respectively.The HI values of PrV were 1.09,1.08 and 1.05 in IMRT5fp,IMRT7fp and 3D- CRTp but with IMRT5fp >IMRT7fp>3D- CRTp(t=3.41、-6.89,P<0.01),respectively.The ratio of dose volume were 0.08,0.10 and 0.19(t=2.79、3.52,P<0.05)in IMRT7fp,IMRT5fp and 3D- CRTp on the small intestine V50,with 0.07,0.10 and 0.19(t=2.58、3.40,P<0.05)in IMRT7fp,IMRT5fp and 3D-CRTp on the bladder V50 and 0.01,0.01 and 0.05(t=3.00、3.17,P<0.01)in IMRT7fp,IMRT5fp and 3D- CRTp on the fomoral head V45.The ratio of dose volume were 0.31 and 0.38(t=3.91,P<0.01)in IMRT7fp and IMRT5fp on the bone marrow V50,with 0.07 and 0.10 in IMRT7fp and IMRT5fp on bladder V45.Conclusions IMRT plan is superior to 3 D- CRT plan in dose conformal degrees of PTV with preoperative radiotherapy of rectal cancer and can significantly protect the normal tissues.The 7-field IMRT plan might be the optimal plan for dose conformal degree and dose uniformity compared with 5-field IMRT.     

乳腺癌保乳术后正向与逆向调强放疗计划的比较

目的 比较乳腺癌调强放疗计划的正向和逆向2种设计模式的区别。方法 针对6例左侧乳腺癌保乳术后的患者应用Pinnacle³7.4f计划系统,分别设计正向和逆向调强放疗计划,在射野方向相同、保证处方剂量线包绕95%靶区体积的前提下,比较2种计划的剂量体积直方图参数和加速器总跳数。结果 2种调强计划相比,正向及逆向调强计划的计划靶区体积适形度指数值分别为0.67±0.06和0.66±0.06(t=2.423,P>0.05),均匀性指数值分别为(28.2±6.0)%和(26.1±6.8)%(t=2.164,P>0.05);左肺V₂₀分别为(18.7±3.3)%和(17.0±2.8)%(t=5.087,P<0.05),V₃₀分别为(15.5±3.0)%和(14.0±2.6)%(t=7.272,P<0.05);心脏V₃₀分别为(4.1±3.1)%和(3.5±2.5)%(t=1.916,P>0.05);机器跳数分别为(262±5)MU和(308±14)MU(t=7.515,P<0.05)。结论 与正向调强放疗计划相比,乳腺癌逆向调强计划中靶区适形度和均匀性无差别,左肺受量降低,心脏受量无差别;但机器跳数显著增加,增加了机器的磨损和治疗实施时间。     

乳腺癌保乳术后全乳加瘤床补量照射不同治疗计划的比较

目的 探讨乳腺癌保乳术后全乳加瘤床照射不同治疗计划靶区剂量适形度、靶区剂量分布均匀性及肺脏、心脏和对侧乳腺受照剂量体积的差异。方法 选择术腔各边界放置银夹且无腋窝淋巴结转移的12 例左侧乳腺癌保乳术后患者, 每例患者分别制定常规放疗(CRT)、无挡肺子野调强放疗(IMRT-F)、挡肺子野调强(IMRT-F-L) 和瘤床同步整合补量调强放疗(SIB-IMRT) 计划。比较不同治疗计划全乳靶区和瘤床靶区的剂量适形度和剂量分布均匀性, 对比不同治疗计划肺脏、心脏和对侧乳腺受照剂量体积。结果 各计划中V_{处方剂量- PTV}1 V_PTV1、V_PTV1 处方剂量 V_PTV2、V_{处方剂量-PTV2 V- 处方剂量、VPTV2-处方剂量 VPTV2组间差异均有统计学意义;CRT 计划中患侧肺V20显著高于不同方式的IMRT 计划, 但不同方式的IMRT 计划之间V20差异无统计学意义;CRT 计划中心脏受照剂量显著高于IMRT 和SIB-I MRT 计划。CRT 计划中对侧乳腺最大照射剂量 Dmax和平均剂量Dmean明显高于不同实现方式的IMRT计划, 但不同实现方式的IMRT 计划中 Dmax和Dmean差异无统计学意义。结论 IMRT-F、IMRT-F-L、SIB-I MRT 计划均显著优于 CRT 计划, 而不同方式I MRT 计划间除个别参数外差异无统计学意义。}     

水平射野对肺癌调强计划结果的影响研究

目的 探讨水平方向射野对肺癌调强计划结果的影响.方法 收集肺癌患者18例,其中左肺癌患者10例,右肺癌患者8例,设计普通调强(IMRT计划)和在普通调强基础上添加一个水平方向射野(H-IMRT计划)的计划,比较机器跳数、子野数及靶区和危及器官(OARs)的剂量分布.结果 两种计划PTV的D_max、D_min及D_mean,患侧肺的V₃₀和D_mean,健侧肺的V₂₀ 和V₃₀,全肺的V₃₀差异均无统计学意义.与IMRT计划相比,添加水平射野后,PTV的均匀性(HI)及适形度(CI)都有显著提高(t=-9.33、10.88,P<0.05);肺的其他剂量指标均变差(t=-1.55~-7.58,P<0.05);心脏的保护更优(t=1.84~3.99,P<0.05);MUs及子野数量降低(t=12.57、3.19,P<0.05).结论 在肺癌的IMRT治疗中,添加水平射野可以改善靶区的剂量分布,但会使肺的低剂量照射体积增加,无益于肺的保护.     

左侧乳腺癌患者根治术后常规调强计划与电子束适形联合调强计划的剂量比较

目的比较左侧乳腺癌患者根治术后常规调强放射治疗计划(intensity modulated radiotherapy, IMRT)与电子束适形放疗(electron beam conformal radiotherapy, EBCRT)联合调强放疗计划的剂量学差异。方法选择2018年6月至2021年10月于宁波市第一医院放化疗中心收治的20例左侧乳腺癌根治术后患者资料, 计划靶区(plan target volume, PTV)包括锁骨上下淋巴结引流区域计划靶区(PTVsc)和患侧胸壁计划靶区(PTVcw), 处方剂量均为50 Gy/25次。所有患者均采用美国Varian Eclipse治疗计划系统(treatment planning system, TPS)设计两种放疗计划, 然后对比两种放疗计划的剂量学参数差异。结果所有20例患者的IMRT计划全部满足临床要求, 与此同时EBCRT联合IMRT计划中有2例患者因患侧肺剂量参数超出本单位的剂量限定标准而不被临床接受, 两例失败计划的胸壁最大深度分别为3.7和4.4 cm, 使用的电子束能量分别为12和15 MeV。其余18例患者的胸...     

直线加速器二级准直器在乳腺癌根治术后调强放疗计划中的应用

目的 探讨乳腺癌根治术后调强放疗（IMRT）计划中固定二级准直器位置对靶区剂量分布和危及器官受照剂量的影响,为临床治疗技术的选择提供依据。方法 选取定位影像资料完整的10例左侧乳腺癌根治术后患者,分别设计两种四野逆向IMRT计划。IMRT-1：采用0°、40°以及两个切线野方向射野,二级准直器的位置不做限制;IMRT-2：保持射野方向和优化参数与IMRT-1相同,0°、40°野二级准直器位置固定在锁骨上区的下界。比较两种IMRT计划的靶区剂量分布、危及器官受照剂量及所需机器跳数（MU）。结果 IMRT-1和IMRT-2的适形指数（CI）分别为0.79和0.73（Z=-2.316,P<0.05）;均匀性指数（HI）两组计划之间差异无统计学意义（P>0.05）;IMRT-2患侧肺V₅、V₁₀、D_mean均低于IMRT-1,差异有统计学意义（Z=-2.805、-2.812、-2.521,P<0.05）;健侧肺平均剂量、心脏平均剂量和健侧乳腺平均剂量IMRT-2均低于IMRT-1,差异有统计学意义（Z=-2.666、-2.701、-2.310,P<0.05）;患侧肺V₂₀、V₃₀和心脏V₃₀在两种计划之间差异均无统计学意义（P>0.05）。结论 在乳腺癌根治术后IMRT计划中,在保证靶区剂量均匀性的情况下,适当固定二级准直器的位置能明显降低危及器官受照的低剂量区,能更好地保护危及器官。     

切向双弧容积弧形调强技术对保乳术后包括内乳淋巴结区照射的心脏剂量学评价

目的 通过对左侧乳腺癌保乳术后患者内乳淋巴结局部放疗,探讨一种新的切向50°双弧容积弧形调强放射治疗（tangential volumetric modulated arc therapy,T-VMAT）技术的剂量学特点,评价T-VMAT对心脏的潜在保护作用。方法 15例左侧乳腺癌保乳术后患者,每例患者分别设计常规加楔形板切线野（W-TF）、6野调强适形放射治疗（6F-IMRT）和T-VMAT计划,靶区处方剂量50 Gy/25次,计算并比较靶区和危及器官（OAR）的剂量体积参数和适形指标。结果 与W-TF相比,T-VMAT技术不仅可降低心脏和冠状动脉前降支（LAD）最大剂量D_max、平均剂量D_mean和≥ 10 Gy剂量区体积（P<0.05）,而且有降低5 Gy剂量区体积V_{5 Gy}趋势,但差异无统计学意义（P>0.05）;与6F-IMRT相比,T-VMAT技术可明显降低心脏的D_mean、V_{5 Gy}、V_{10 Gy}和V_{20 Gy},以及LAD的D_mean、V_{5 Gy}和V_{10 Gy}（P<0.05）。与W-TF相比,T-VMAT计划中同侧肺V_{20 Gy}和健侧乳腺V_{5 Gy}均未增加,差异无统计学意义（P>0.05）,且靶区剂量覆盖和适形度均明显优于W-TF,热点体积V₁₁₀明显低于W-TF（P<0.05）。结论 在不增加同侧肺和健侧乳腺受照体积的同时,T-VMAT不仅可以降低心脏和LAD高剂量区受照体积,而且有降低心脏和LAD低剂量区受照体积的趋势。     

乳腺癌根治术后双弧VMAT与IMRT计划的剂量学比较

目的 比较乳腺癌根治术后双弧的容积旋转调强放射治疗(VMAT)与5野的静态调强放射治疗(IMRT)2种计划之间的剂量学差异,评估VMAT技术在乳腺癌根治术后的剂量学特点与应用能力.方法 选取28例乳腺癌根治术后患者(左侧10例,右侧18例),分别制定双90度弧段的VMAT与5野的IMRT 2种计划,主要的计划评估参数为靶区的肿瘤控制概率(TCP)、适形指数(CI)、均匀指数(HI)以及接受相应处方剂量水平照射体积百分比V₉₅、V₁₁₀,危及器官(OAR)评估包括患侧肺的正常组织并发症概率(NTCP)、D_mean、V₅、V₂₀、V₃₀,心脏的NTCP值、D_mean、V₂₅,健侧乳腺的D_mean、机器跳数(MU)以及治疗时间.结果 VMAT计划与IMRT计划的TCP值分别为(96±2)%、(90±2)%(t=-6.28,P<0.01);HI值分别为0.15±0.04,0.22±0.02(t=13.29,P<0.05);肿瘤位于左侧时,心脏NTCP值在VMAT计划与IMRT计划中分别为(1.0±0.12)%,(1.7±0.13)%(t=2.14,P<0.05);肿瘤位于右侧时,2种计划心脏的NTCP差异无统计学意义,平均剂量分别为(3.27±0.26)、(6.0±0.47)Gy(t=9.21, P<0.01);VMAT计划在MU少于IMRT计划(t=9.58,P<0.01),治疗时间短于IMRT计划(t=8.40,P<0.05).结论 乳腺癌根治术后,VMAT计划具有更强的临床应用能力,且表现出更优的剂量学特点.     

基于深度学习的乳腺癌保乳术后调强放疗剂量分布预测

目的研究基于深度学习的方法预测乳腺癌保乳术后调强放疗(IMRT)剂量分布, 并评估其预测精度。方法回顾性分析2018年1月至2023年3月在上海国际医学中心接受IMRT的110例左侧乳腺癌保乳术后患者的调强放疗数据, 随机固定选择80例作为训练集, 随机固定10例作为验证集, 剩余20例作为测试集。首先将患者的计算机体层成像(CT)图像、感兴趣区、体素与靶区距离和对应的剂量分布四通道特征作为输入数据, 然后使用U-net网络进行训练得到预测模型, 利用该模型对测试集进行剂量预测, 验证体素与靶区距离特征在剂量预测中的影响, 并将剂量预测结果与实际手动计划剂量进行比较。结果加入体素与靶区距离特征的模型使预测精度更高, 测试集中20例患者的剂量评分和剂量体积直方图(DVH)评分分别为2.10±0.18和2.28±0.08, 与手动计划剂量分布更加接近(t=2.52、2.40, P<0.05)。靶区和危及器官(OAR)的剂量预测结果与手动计划剂量的偏差在4%以内, 健侧乳腺平均剂量增加了13 cGy, 均在临床可接受范围内。除PTV60的D2、D98(Di为i%的PTV体积接受的剂量)...     

浸润型胸腺瘤术后单能与混合能量光子束调强放疗计划剂量学分析

目的 比较浸润型胸腺瘤术后患者单能与混合能量光子束调强放射治疗(IMRT)计划之间剂量学差异,探讨混合能量光子束计划在临床的应用价值。方法 随机抽取12例胸腺瘤术后病例的CT定位图像,在治疗计划系统上勾画临床靶体积(CTV)并外扩为计划靶体积(PTV)、危及器官(OAR)及其他正常组织。每个病例分别制定6和10 MV与混合能量光子束的3种固定野调强放疗(FF-IMRT)计划,优化与计算剂量后统计各种计划的机器跳数(MU),并使用剂量体积直方图(DVH)工具比较PTV的体积剂量、适形指数(CI)、均匀指数(HI)和OAR剂量。结果 PTV近似最大剂量D_2%混合能量光子束计划优于6 MV光子束(t=3.107,P <0.05);6 MV光子束HI与混合能量光子束计划比较,差异有统计学意义(t=2.924,P<0.05);CI三者之间差异均有统计学意义。6 MV计划的MU大于10 MV及混合光子束计划。双侧肺V₅、V₁₀、V₂₀、V₃₀和平均剂量(D_mean)指标各个类型计划之间大部分差异有统计学意义,且混合能量光子束计划优于其他两种计划。心脏V₃₀、V₄₀指标6 MV与混合光子计划的结果接近,但均优于10 MV光子束的计划。结论 混合能量光子束IMRT计划如果合理选择射野角度和射野数量,依据入射角度选择光子束的能量,可充分利用低能及高能光子束的不同特点,总体上可以改善IMRT计划的质量,对于浸润型胸腺瘤术后病例具有一定的临床参考价值。     

左乳癌保乳术后混合调强放疗中利用多叶准直器遮挡技术减少心脏受照剂量的研究

目的 利用多叶准直器（MLC）遮挡技术减少左侧乳腺癌患者保乳术后混合调强放疗中心脏的受照剂量,降低放射性心脏损伤发生的风险。方法 选取18例左乳癌保乳术后患者,在自由呼吸状态下获取3DCT和4DCT图像。利用4DCT在3DCT图像上确定出靶区并分别制定混合调强治疗计划（H_IMRT）和为降低心脏受量而引入MLC遮挡技术的治疗计划（HSH_IMRT）,利用Compass系统对治疗计划进行剂量学验证。靶区处方剂量为50 Gy,分25次完成。比较两种治疗计划结果与剂量验证结果中靶区及危及器官的剂量学参数。结果 计划结果显示,与H_IMRT比较,HSH_IMRT靶区剂量均匀性更好,适形度差异无统计学意义（P>0.05）;全心脏D_mean较前者降低23.67%（t=13.693,P<0.05）,心脏其他亚结构的D_max和D_mean均较前者下降。剂量验证结果显示,两种计划靶区剂量均匀性与适形度差异无统计学意义（P>0.05）;HSH_IMRT与H_IMRT比较,全心脏的D_mean降低24.88%（t=13.782,P<0.05）;除左心室、右心室外,其他心脏亚结构的D_max以及所有心脏亚结构的D_mean均降低。患侧肺的V₂₀和D_mean在计划结果与验证结果中均显示HSH_IMRT更低。结论 在H_IMRT中合理引入MLC遮挡技术能够在保证其剂量学优势的前提下更多地减少心脏组织的受量,进一步降低心脏发生放射性损伤的风险。