快速旋转调强与固定射野动态调强在直肠癌术前放疗中的剂量学比较

目的 比较快速旋转调强(RapidArc)与固定射野动态调强(dIMRT)两种放射治疗技术在直肠癌术前放疗中的剂量学差异.方法 采用两种治疗技术对10例Ⅱ、Ⅲ期直肠癌术前患者设计同步加量治疗计划.处方剂量为GTV 50.6 Gy,分22次;PTV41.8 Gy,分22次,危及器官限量参考临床常规要求.在95%体积的PTV达到处方剂量前提下,比较两种计划的剂量体积直方(DVH)图、靶区和危及器官剂量、靶区剂量适形度、剂量分布均匀性、机器跳数以及治疗时间.结果 RapidArc计划中,GTV和PTV的靶区剂量适形度较高(t=7.643、8.226,P＜0.05);而靶区剂量均匀性略低于dIMRT(t=-10.065、-4.235,P＜0.05).RapidArc计划中大、小肠的平均受量显著低于dIMRT计划(t=2.781,P＜0.05).膀胱平均受照剂量略低于dIMRT,股骨头的平均受量略高于dIMRT,但差异无统计学意义.RapidArc计划机器跳数减少48.5%,平均治疗时间节省79.5%.结论 RapidArc与dIMRT计划在直肠癌术前放射治疗的剂量学上无明显差异.RapidArc每次治疗时间明显缩短,减少了治疗期间患者非主观运动引起的误差,总的机器跳数降低,减少了正常组织照射.

Abstract：

Objective To compare the dosimetric difference between RapidArc and fixed gantry angle dynamic intensity modulated radiotherapy (dIMRT) in developing the pre-operative radiotherapy for rectal cancer patients.Methods Two techniques,RapidArc and dIMRT,were used respectively to develop the synchronous intensity modulated plans for 10 stage Ⅱ and Ⅲ rectal cancer patients at the dose of gross tumor volume (GTV) of 50.6 Gy divided into 22 fractions and planning target volume (PTV) of 41.8 Gy divided into 22 fractions.Both plans satisfied the condition of 95% of PTV covered by 41.8 Gy.The dose-volume histogram data,isodose distribution,monitor units,and treatment time were compared.Results The two kinds of dose volume histogram (DVH) developed by these two techniques were almost the same.The conformal indexes of GTV and PTV by RapidArc were better than those by dIMRT (t =7.643,8.226 ,P < 0.05),while the homogeneity of target volume by dIMRT was better (t =-10.065,-4.235 ,P <0.05).The dose of rectum and small bowel planned by RapidArc was significantly lower than that by dIMRT (t =2.781 ,P <0.05).There were no significant differences in the mean doses of bladder and femoral head between these two techniques.The mean monitor units of RapidArc was 475.5,fewer by 48.5% in comparison with that by the dIMRT (924.6).The treatment mean time by RapidArc was 1.2min,shorter by 79.5% in comparison with that by dIMRT (5.58 min).Conclusions There is no significant dosimetric difference between the two plans of RapidArc and dIMRT.Compared with dIMRT,RapidArc achieves equal target coverage and organs at risk(OAR) sparing while using fewer monitor units and less time during radiotherapy for patient with rectal cancer.     

容积旋转调强与固定野动态调强在宫颈癌术后放疗的剂量学比较

目的 比较容积旋转调强（RapidArc）与固定野动态调强（IMRT）两种宫颈癌术后放疗的剂量学参数及急性不良反应发生率,为临床治疗技术的选择提供参考依据。方法 选取35例宫颈癌术后盆腔预防放疗患者,其中,17例接受RapidArc,18例接受IMRT,处方剂量50 Gy,共25次。比较两组治疗计划的剂量-体积直方图（DVH）、靶区剂量适形度、均匀性、靶区及危及器官的剂量、机器跳数及治疗时间;对比两组患者治疗期间的急性肠道及膀胱反应发生率。结果 与IMRT相比,RapidArc靶区剂量适形度较高（t=3.13,P<0.05）,但均匀性略低（t=-4.25,P<0.05）;RapidArc计划中股骨头V₂₀、V₃₀均低于IMRT（t=2.56、2.34,P<0.05）;RapidArc计划机器跳数减少了52.1%,治疗所需时间缩短了46.8%。两组患者肠道、膀胱急性不良反应发生率相近。结论 对于宫颈癌术后盆腔预防放疗患者,采用RapidArc或IMRT技术均可达到靶区的剂量要求及保护危及器官的目的。RapidArc计划靶区剂量学参数、急性不良反应发生率与IMRT计划比较未见明显优势,但机器跳数与出束时间明显优于IMRT计划,实现了治疗效率的大幅提高。     

快速旋转调强与五野动态调强在乳腺癌 保乳术后放疗中的剂量学比较

目的 比较乳腺癌保乳术后RapidArc计划与五野动态调强(5F-IMRT)计划的剂量学差异。方法 选择8例左侧乳腺癌保乳术后女性患者,处方剂量为50 Gy/ 25次。分别设计RapidArc计划与5F-IMRT计划。比较两种计划的靶区适形度指数、均匀性指数、靶区覆盖度和危及器官的受照剂量体积,同时比较两组计划实施时的治疗时间和机器跳数。结果 在两种计划的靶区比较中,RapidArc计划的靶区适形度指数为(0.88±0.03),高于5F-IMRT计划的(0.79±0.02)(t=8.28,P<0.05);RapidArc计划的均匀性指数为(9.01±0.73),优于5F-IMRT计划的(10.44±1.08)(t=-2.73,P<0.05)。两组计划在同侧肺受照剂量体积比较中RapidArc计划的D_mean、V₁₀、V₂₀、V₃₀小于5F-IMRT计划(t=-7.53、-7.20、-8.39、-7.80,P<0.05),但RapidArc计划中的V₅较5F-IMRT计划增加了约16% (t=5.67,P<0.05);心脏的受照剂量体积比较中RapidArc计划中的D_mean、V₅、V₁₀均高于5F-IMRT(t=10.46、28.76、5.40,P<0.05),但在RapidArc计划中心脏的V₃₀低于5F-IMRT (t=-6.12,P<0.05)。对侧肺和对侧乳腺的V₅在RapidArc计划中明显高于5F-IMRT计划 (肺:t=21.50,P<0.05;乳腺:t=5.44,P<0.05)。RapidArc计划中机器跳数减少了25%,平均治疗时间节省了60%。结论 乳腺癌保乳术后RapidArc计划与5F-IMRT计划比较提高了靶区的适形度和均匀度,减少了高剂量区的受照体积,降低了机器跳数,缩短了治疗时间,但增加了正常组织低剂量区的受照体积。     

旋转调强与固定野调强治疗肝癌的剂量学比较

目的 比较旋转调强(RapidArc)与固定野调强放疗(IMRT)在肝癌治疗计划中的剂量学差异。方法 选择10例肝癌患者的CT数据,分别设计IMRT计划与单弧(RA1)和双弧(RA2)计划,比较设计计划的靶区剂量分布、危及器官受量、正常组织受量、机器跳数以及治疗时间。结果 RA1和RA2计划靶区剂量的最大值都低于IMRT(Z=-2.090、-2.666,P＜0.05),计划90%的处方剂量的适形指数低于IMRT(Z=-2.805、-2.809,P＜0.05);危及器官胃与小肠的V40也比IMRT计划低。但IMRT左肾平均剂量低于RapidArc计划组(Z=-1.988、-2.191,P＜0.05);正常组织的V₅、V₁₀和V₁₅IMRT计划低于RapidArc计划组,V20、V25和V30IMRT计划高于RapidArc计划组。RapidArc计划机器跳数是IMRT计划的40%和46%,治疗时间是IMRT计划30%和40%。结论 两种技术设计的计划剂量分布均能满足临床要求,并且剂量分布基本一致。RapidArc计划的适形指数优于IMRT,危及器官剂量也比IMRT计划略有降低,正常组织的低剂量区RapidArc计划组与IMRT相比有先高后低的趋势,并且机器跳数少,治疗时间短。     

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

目的 比较旋转调强(RapidArc)与固定野调强(IMRT)放疗在颅脑多发转移瘤中的剂量学差异。方法 针对10例多发脑转移瘤患者分别设计3种放疗计划:固定野逆向调强(IMRT),RapidArc单弧旋转调强(RA1),双弧旋转调强(RA2)。在保证计划均满足临床要求前提下,分别比较3种计划的靶区剂量分布、危及器官及靶区外正常组织的受照剂量、机器跳数以及治疗时间,探讨其剂量学差异。结果 3种计划均满足临床要求,在靶区适形度和均匀性方面,RA2计划优于IMRT(Z＝-2.803、-2.094,P<0.05)和RA1(Z＝-2.448、-2.191,P＜0.05),RA1计划与IMRT计划差别不大。RA1、RA2计划中的双侧晶体、双侧眼球、脑干的最大剂量均显著低于IMRT(Z＝-2.803～-2.191,P <0.05)。RA2计划评估的双侧视神经最大剂量均显著低于IMRT(Z＝-2.293、-2.701,P<0.05)。RA1、RA2计划中的机器跳数相对于IMRT平均分别减少了43%和24%,缩短了治疗时间。结论 单弧和双弧旋转调强计划均可达到或优于IMRT计划的靶区剂量分布,能更好地降低部分危及器官的受照剂量,同时可以显著降低机器跳数和治疗实施时间。     

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.     

宫颈癌术后容积旋转调强放疗与5野调强放疗计划的剂量学比较

目的比较宫颈癌术后容积旋转调强放疗（VMAT）与5野调强放疗（5F-IMRT）计划的剂量学差异,并在危及器官保护方面进行分析。方法选择10例宫颈癌术后放疗的5F-IMRT计划,按相同的剂量限制对每例患者行单弧VMAT和双弧VMAT计划设计,比较3种计划的靶区剂量、适形度指数、均匀性指数、危及器官剂量及加速器跳数。组间比较采用单因素方差分析检验,组间两两比较采用LSD检验。结果单弧VMAT和双弧VMAT均能满足靶区处方剂量的要求,在靶区最大剂量、平均剂量、适形度指数和均匀性指数上,双弧VMAT与5F-IMRT计划相当,单弧VMAT计划最差,差异有统计学意义（F=24.102、13.710、5.919、11.045,均P < 0.05）;靶区最小剂量比较,3种计划差异无统计学意义（F=3.323,P>0.05）。单弧VMAT和双弧VMAT计划的加速器跳数明显少于5F-IMRT计划,差异有统计学意义（F=295.138,P < 0.05）。对于小肠、直肠和膀胱的参数最大剂量,双弧VMAT与5F-IMRT计划相当,单弧VMAT计划最差,差异有统计学意义（F=16.069、7.521、13.966,均P < 0.05）。对于膀胱的参数V20、V30和V40（V表示受照剂量体积百分比）,5F-IMRT优于单弧VMAT和双弧VMAT,差异有统计学意义（F=5.142、20.095、7.387,均P < 0.05）。对于左股骨头参数V20和V30,单弧和双弧VMAT优于5F-IMRT,差异有统计学意义（F=3.717、16.040,均P < 0.05）。对于右股骨头参数V30和V40,单弧和双弧VMAT优于5F-IMRT,差异有统计学意义（F=10.873、7.791,均P < 0.05）。结论宫颈癌术后放疗,双弧VMAT计划在靶区剂量学参数上与5F-IMRT计划相当,单弧VMAT计划较差。在危及器官保护方面,3种计划各有优势,但VMAT计划的加速器跳数明显减少,可以提高治疗效率,值得进一步研究。     

胸上段食管癌螺旋断层放疗和容积旋转调强放疗的剂量学比较

目的 比较胸上段食管癌螺旋断层(HT)与容积旋转调强放疗(VMAT)计划的剂量学差异。方法 随机抽样法选取10例胸上段食管癌患者,分别设计HT和VMAT双弧照射调强放疗计划,肿瘤靶区体积(GTV)给予66 Gy/30次,计划靶区体积(PTV)给予50 Gy/30次。根据剂量体积直方图(DVH)评价靶区的D_1%、D_5%、D_95%、D_99%、适形指数(CI)、均匀性指数(HI)和危及器官(OAR)受量,比较治疗时间和机器跳数(MU)的差异。结果 HT组GTV和PTV的D_99%高于VMAT组(t=4.476、3.756,P<0.05);GTV与PTV的D_1%、D_5%、D_95%、HI和CI差异均无统计学意义(P>0.05)。HT组全肺V₁₀、V₁₅、V₂₀和全肺平均剂量(MLD)均显著低于VMAT组(t=-3.369、-4.824、-4.869、-3.657,P<0.05);全肺V₅、V₃₀和脊髓D_max差异均无统计学意义(P >0.05)。HT组治疗时间和MU数均远大于VMAT组(t=13.970、7.982,P<0.05)。结论 HT与VMAT技术均能满足胸上段食管癌放疗剂量要求。HT技术能显著减小双肺受量,而VMAT技术具备明显的效率优势。     

算法和射野设置对肺癌容积旋转调强计划的剂量学影响

目的 分析不同剂量计算算法和不同射野设置对肺癌容积旋转调强计划(VMAT)的剂量学差异,为临床计划设计提供参考。方法 选择20例肺癌患者,分别设计4组VMAT计划:基于各向异性解析算法(AAA)的2野2弧(2F2A_AAA)、基于外照射光子剂量算法(AXB)射的2野2弧 (2F2A_AXB)、基于蒙特卡罗算法(MC)的2野2弧(2F2A_MC)、基于MC算法的1野2弧(1F2A_MC)。分别对不同算法、不同射野设置的计划,在靶区覆盖、高量控制、剂量均匀性指数(HI)、适形性指数(CI),以及危及器官(OARs)受照剂量进行评估。结果 3组不同算法的2F2A计划靶区结果表明,2F2A_MC在PGTV的D_1%和V_95%(受到95%处方剂量所包绕的靶区相对体积)上均优于2F2A_AAA(D_1%:t=-2.44,P=0.03;V_95%:z=-2.04,P=0.04)和2F2A_AXB(D_1%:t=2.34, P=0.03; z=-3.21,P<0.01)。 2F2A_AXB在PGTV的CI表现上优于2F2A_AAA(z=-3.66,P<0.01),与2F2A_MC相当。就危及器官而言,2F2A_AXB和2F2A_MC全肺的V_{5 Gy}上分别较2F2A_AAA减少了0.68%(z=-2.69,P=0.01)和3.05%(z=-3.52,P<0.01)。2F2A_AXB计划在全肺D_mean为1776.44 cGy,均优于2F2A_MC(t=2.67,P=0.02)和2F2A_AAA(t=8.62,P<0.01)。2F2A_AXB的Body_5mm在V_{20 Gy}相较于2F2A_AAA和2F2A_MC分别减少了1.45%(z=-3.88,P<0.01)和2.01%(z=-3.66, P<0.01)。而不同射野设置的两组计划结果表明,1F2A_MC在PTV1的CI和PTV2的HI上均优于2F2A_MC(CI: t=2.61, P=0.02; HI: z=-2.20, P=0.03)。1F2A_MC在全肺D_mean相对于2F2A_MC增加了26.29 cGy(t=2.28,P=0.04)。结论 在进行肺癌VMAT计划设计时,MC算法适用于靶区优先,AXB算法适用于危及器官优先;而仅有MC算法的情况下,靶区优先时推荐选择1F2A,危及器官优先时推荐选择2F2A。     

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.     

容积旋转调强放疗和常规调强放疗技术在乳腺癌保乳术后同步推量中的剂量学比较

 目的 比较容积旋转调强放疗(VMAT)和常规调强放疗(IMRT)两种技术在乳腺癌保乳术后同步推量放疗中剂量学差异。方法 随机选择10例左侧乳腺癌保乳术后患者,使用MONACO 5.1计划系统,分别设计VMAT和IMRT计划,处方剂量均为PTV_50Gy/25 f、PGTVtb60 Gy/25 f,评估两种计划靶区剂量适形指数(CI)、均匀性指数(HI),以及正常器官受照剂量(Gy)、机器跳数(MU)及治疗时间。结果 VMAT计划中靶区剂量的适形度明显优于IMRT(P<0.05),而患侧肺V₅、V₁₀、V₂₀及健侧肺V₅稍高于IMRT组(P<0.05)。结论 对于乳腺癌保乳术后同步推量放疗,VMAT和IMRT计划都可以满足临床剂量学的要求,VMAT在适形度方面对于IMRT计划有优势,并缩短了治疗时间。     

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.     

胸上段食管癌无均整器容积弧形调强与固定野调强放疗计划的剂量学比较

目的 探讨在瓦里安TrueBeam^TM直线加速器中使用无均整器出束容积弧形调强(RA-FFF)及常规固定野调强(IMRT)两种计划剂量学差异.方法 选择10例分期为cT_2-3N_0-1M_0-1a胸上段食管癌患者定位CT资料,使用ECLIPSE^TM 10.0.4治疗计划系统分别设计RA-FFF、IMRT根治性放疗计划,处方剂量为60 Gy/30次,比较2种计划的剂量学参数和执行效率.结果 2种计划靶区适形度相似,差异无统计学意义;IMRT计划的均匀性指数高于RA-FFF计划(t=7.298,P=0.008);RA-FFF计划中肺组织的V₂₀、V₅低于IMRT计划(t=2.451、2.604,P<0.05).RA-FFF及IMRT两种计划制定时间分别为(5.3±1.4)、(3.5±1.7)h(t=2.585,P<0.05),机器总跳数分别为632±213及734±132(t=-1.287,P=0.084),治疗执行时间分别为(2.2±0.9)、(4.5±1.3)min(t=4.60,P<0.01).结论 与IMRT计划相比,RA-FFF在胸上段食管癌治疗中具有相似的靶区剂量分布,可更好地保护肺组织,计划制定时间较长但执行效率较高.     

RapidArc联合主动呼吸控制技术应用于胸段食管癌调强放疗的剂量学研究

目的 探讨RapidArc联合主动呼吸控制(ABC)技术在胸段食管癌调强放疗的剂量学特点.方法 选取10例接受放疗的胸段食管癌患者,在ABC辅助下选择吸气末屏气触发方式(mDIBH),触发阈值设定为呼吸曲线峰值的80％,和自由呼吸(FB)状态下分别行定位CT扫描,应用三维治疗计划系统为每例患者设计FB下的IMRT(IMRT-FB)和双弧RapidArc( Arc-FB)、mDIBH下的3个小弧RapidArc( Arc-A BC)3种调强放疗计划.评价靶区的D2％、D98％、V95,均匀指数(HI)和适形指数(CI),正常组织的相关剂量体积参数Vx,以及总机器跳数(MU)、总控制点数( control points)和治疗时间.结果 PTV的平均体积由FB下的376 cm3减少到了mDIBH下的260cm3.mDIBH下的双肺平均体积为5964.6 cm3,而FB则为3838.8 cm3,增加了35％;mDIBH和FB状态下平均心脏体积分别为524.4和642.7 cm3.Arc-ABC计划靶区的CI、HI及D2％、D98％、V95与IMRT-FB和Arc-FB计划差异无统计学意义,双肺的V10、V20、V30、V40及平均剂量(Dmean)明显低于IMRT-FB和Arc-FB(F=4.38、5.34、4.07、3.89、4.28,P＜0.05),心脏的V20、V30、V40、Dmean及脊髓Dmax有不同程度的下降,但差异无统计学意义.Arc-ABC计划的总机器跳数和子野数也明显少于IMRT-FB计划(F=26.86、12.56,P＜0.05).结论 RapidArc联合ABC在胸段食管癌精确放疗中具有提高靶区剂量和降低肺组织受照剂量的作用.     

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...     

宫颈癌放疗中的快速旋转调强计划和调强计划比较

目的 探讨快速旋转调强(RapidArc)计划和固定野调强计划(IMRT)的优劣.方法 选择10例宫颈癌病例,在Eclipse 8.6计划系统上分别对其进行单弧、双弧及三弧RapidArc和固定野凋强放疗计划设计,依次分别用Arc 1、Arc 2、Arc 3和IMRT表示.比较4者的计划制作及治疗时间、靶区及危及器官剂量分布差异.结果 10例病例的Arc 1、Arc 2、Arc 3和IMRT计划设计时间平均值分别为112、131、154和46 min,在瓦里安IX加速器上的治疗时间平均值分别为2.15、3.32、4.48和6.95 min,平均剂量分别为48.99、49.40、49.51和48.65 Gy,靶区均匀指数分别为1.11、1.07、1.06和1.12,靶区适形指数分别为0.73、0.87、0.87和0.79.IMRT计划的直肠、膀胱和小肠等危及器官受量最小,4种计划的股骨颈受量相似.结论 RapidArc计划在靶区剂量分布、均匀度、适形度以及治疗时间方面占优势,IMRT计划在计划的剂量计算时间和危及器官的保护方面占优势.总体临床应用上RapidArc计划优于IMRT计划.

Abstract：

Objective To explore the advantages and disadvantages between the RapidArc plans and fixed-field IMRT plan (IMRT).Methods Ten cases of cervical cancer,aged 55 (36-70),who were to receive post-operative radiotherapy were selected randomly.Single arc (Arc 1),two arcs (Arc 2),and three arc (Arc 3) RapidArc plans and fixed-field IMRT plan were designed respectively in the Eclipse 8.6 planning system.The designing,treatment time,target area,and dose distribution of organs at risk by these 4 planning techniques were compared.Results The values of average planned treatment time by the Arc 1,Arc 2,and Arc 3 ten cases was 98,155,185,and 46 min,respectively.The values of average treatment time in the Varian IX accelerator were 2.15,3.32,4.48,and 6.95 min,respectively.The average mean doses were (48.99±1.08),(49.40±0.51) ,(49.51±0.62) ,and (48.65±0.92) Gy,respectively.The values of homogeneity index (HI) of target were 1.11±0.07,1.07±0.02,1.06±0.02,and 1.12±0.05,respectively.The values of eonformal index (CI) of target were 0.73±0.13,0.87±0.06,0.87±0.06,and 0.79±0.06,respectively.The doses at rectum,bladder,and small intestine calculated by IMRT plan were the lowest,and the doses at the femoral neck calculated by these 4 plans were similar.Conclusions The RapidArc plan is superior in dose distribution at target,HI,CI,and treatment time to IMRT,but IMRT plan is superior to RapidArc in planned dose calculation time and protection of organs at risk.However,in general,the RapidArc plan is better in clinical application than IMRT plan.