食管癌调强放疗计划剂量学验证研究

目的 对比分析食管癌调强放疗(IMRT)计划的三种剂量验证方法.方法 使用Pinnacle 8.0 h计划系统完成7例食管癌IMRT计划,选用二、三维剂量验证设备MATRIXX和Delta4完成测量验证.IMRT原计划和Delta4移植计划使用蒙特卡罗方法重新计算.评价MATRIXX和Delta4测量的gamma通过率;Pinnacle计算,Delta4测量与蒙特卡罗模拟结果分别比较gamma图,中心层面剂量分布,剂量曲线和剂量体积直方图.结果 gamma误差设定为3%/3 mm,MATRIXX测量通过率＞98%,Delta4测量通过率为94.4%,其中有4个射野＜90%.Delta4测量和蒙特卡罗模拟比较,误差限定为2 mm/2%和3 mm/3%时,gamma通过率分别为97.6%和99.8%.Pinnacle计划系统计算的中心层面剂量分布、剂量曲线与蒙特卡罗模拟计算结果、Delta4测量结果比较一致.Delta4测量与蒙特卡罗模拟计算的剂量体积直方图一致性很好,均与Pinnacle计划系统计算略有差异.结论 3种方法均能完成食管癌IMRT计划的验证,蒙特卡罗和Delta4方法在验证过程中无数据丢失.Delta4实现了三维的剂量验证,蒙特卡罗能够在每个患者的实际CT图像上进行模拟计算.

Abstract：

Objective To compare the results of three dose verification solutions of esophageal carcinoma IMRT plans. Methods Seven esophageal carcinoma cases were planned with Pinnacle 8.0 h.The MATRIXX and Delta4 were chosen as the two-dimensional dosimetry and three-dimensional dosimetry.IMRT plans and Delta4 phantom plans were also recalculated by Monte Carlo. Gamma values were evaluated for MATRIXX and Delta4 with 3 mm/3% gamma criteria. For the comparison of Pinnacle, Delta4 and Monte gamma maps, the dose distribution in central plane, dose profiles and dose-volume histograms were used to evaluate the agreement. Results The gamma maps comparison show that with 3 mm/3% gamma criteria an over 98% pass ratio was obtained by MATRIXX measurement. A 94. 4% gamma pass ratio whicl.contains 4 fields gamma pass ratio lower than 90%, was obtained by Delta4 measurement. A 97.6% and 99. 8% gamma pass ratio was obtained between the Delta4 measurement and Monte Carlo simulation with 2 mm/2% and 3 mm/3% gamma criteria. The dose distribution in central plane and dose profiles from Pinnacle calculation were almost in agreement with both the Monte Carlo simulation and Delta4 measurement. The DVH plot have slightly differences between Pinnacle and Delta4 measurement as well as Pinnacle and Monte Carlo simulation, but have excellent agreement between Delta4 measurement and Monte Carlo simulation. Conclusions It was shown that all the three methods can be used very efficiently to verify esophageal carcinoma IMRT delivery, Delta4 and Monte Carlo simulation no data missed. The primary advantage of Delta4 is the fact it can measure true 3D dosimetry while Monte Carlo can simulate in patients CT images but not in phantom.     

颈段食管癌质子治疗与调强放疗计划对比研究

目的 比较质子治疗(PT)与X线调强放疗(IMRT)在颈段食管癌治疗中的剂量分布.方法 选取10例颈段食管癌患者CT图像,每例制定1个X线IMRT计划(7个野)与2个PT计划(PT1为前后对穿2个野,PT2为两前斜加后3个野).使用等剂量分布及剂量体积直方图进行计划间比较.结果 IMRT与PT1、PT2计划的计划靶体积(PTV)95%等剂量面适形指数分别为1.43与1.52、1.43(F=3.62,P<0.01),平均剂量分别为64.4 Gy与65.0、63.6 Gy(F=12.06,P<0.01);PTV周围正常组织平均剂量分别为20.7 Gy与10.5、10.6 Gy(F=77.60,P<0.01),全肺的为12.1 Gy与7.3、8.4 Gy(F:15.87,P<0.01),脊髓最大剂量分别为41.4 Gy与34.9、35.0 Gy(F=11.74,P<0.01).结论 3个计划均能满足覆盖靶区要求,但PT可明显降低肿瘤周围正常组织剂量,这为PT剂量提升或合并使用同期化疗提供了可能.PT计划中前后对穿2个野也可满足临床要求.

Abstract：

Objective To compare the dosimetric difference of proton therapy(PT)and X-ray intensity-modulated radiotherapy(IMRT)for cervical esophageal cancer.Methods The treatment planning of 10 patients with cervical esophageal cancer were selected for this study.One IMRT plan and 2 PT plans (PT1 plan:two opposed AP-PA beams;PT2 plan:two anterior-oblique beams and one posterior beam)were constructed for each patient.The isodose distribution and statistical data extracted from dose volume histograms were used for dose plan comparison.Results The conformal index(CI95%,defined as the ratio between the volume receiving at least 95%of the prescribed dose and the volume of PTV)of IMRT,PT1 and PT2 was 1.43,1.52 and 1.43(F=3.62,P<0.01),respectively.And the mean dose of PTV was 64.4 Gy,65.0 Gy and 63.6 Gy(F=12.06,P<0.01);the mean dose in normal tissue outside of PTV was 20.7 Gy,10.5 Gy and 10.6 Gy(F=77.60,P<0.01),in whole lung was 12.1 Gy,7.3 Gy and 8.4 Gy (F=15.87,P<0.01);the maximum dose in spinal cord was 41.4 Gy,34.9 Gy and 35.0 Gy(F=11.74,P<0.01),respectively.Conclusions Ail plans full file the requirements for PTV,however.PT plans can reduce radiation dose in surrounding normal significantly.The possibility is provided to escalate PT dose in PTV or to combine more aggressive chemotherapy.The PT1 plan full fills the clinical requirements.     

乳腺癌保乳术后常规、三维适形及两种调强放疗技术剂量学评估(英文)

Objective: The purpose of this study was to compare the dose distribution and dose volume histogram (DVH) of the planning target volume (PTV) and organs at risk (OARs) among conventional radiation therapy (CR), three-dimensional conformal radiation therapy (3DCRT), two-step intensity-modulated radiation therapy (TS-IMRT) and direct machine parameter optimization intensity-modulated radiation therapy (DMPO-IMRT) after breast-conserving surgery. Methods: For each of 20 randomly chosen patients, 4 plans were designed using 4 irradiation techniques. The prescribed dose was 50 Gy/2 Gy/25 f, 95% of the planning target volume received this dose. The cumulated DVHs and 3D dose distributions of CR, 3DCRT, TS-IMRT and DMPO-IMRT plans were compared. Results: For the homogeneity indices, no statistically significant difference was observed among CR, 3DCRT, TS-IMRT and DMPO-IMRT while the difference of the conformality indices were statistically significant. With regard to the organs at risk, IMRT and 3DCRT showed a significantly fewer exposure dose to the ipsilateral lung than CR in the high-dose area while in the low-dose area, IMRT demonstrated a significant increase of exposure dose to ipsilateral lung, heart and contralateral breast compared with 3DCRT and CR. In addition, the monitor units (MUs) for DMPO-IMRT were approximately 26% more than those of TS-IMRT and the segments of the former were approximately 24% less than those of the latter. Conclusion: Compared with CR, 3DCRT and IMRT improved the homogeneity and conformity of PTV, reduced the irradiated volume of OARs in high dose area but IMRT increased the irradiated volume of OARs in low dose area. DMPO-IMRT plan has fewer delivery time but more MUs than TS-IMRT.     

子宫颈癌术后盆腔转移三维适形与调强放疗剂量学对比研究

目的 比较三维适形放疗(3DCRT)和调强放疗(IMRT)在子宫颈癌术后盆腔转移病灶靶区(PTY)剂量覆盖和危及器官(OAR)保护方面的差异,探讨子宫颈癌术后盆腔转移病灶的最佳治疗方案.方法 选择10例子宫颈癌根治术后盆腔转移患者,行CT模拟定位后将数据上传至Varian三维计划系统,勾画靶区,进行放疗计划设计后做下列研究:3DCRT计划与IMRT计划对计划靶区PTV的影响及比较;3DCRT计划与IMRT计划中危及器官受最比较分析.结果 采用95%可信区间,CTV至PTV的外放边界定为1 cm.3DCRT计划中3、4、5和6个射野下PTV适形指数分别为0.46、0.67、0.68、0.68,4个以上射野数日的增加不再显著改善靶区分布和减少正常组织受照射体积百分比.IMRT计划中5、7、9、11和13个射野下PTV适形指数分别为0.75、0.83、0.84、0.85、0.85,9个以上射野数目增加不再显著改善靶区分布和减少正常组织受照体积百分比.比较OAR最高照射剂量,IMRT计划中小肠脊髓的最高照射剂量低于3DCRT,直肠膀胱及股骨头的最大剂量差异无统计学意义.结论 子宫颈癌术后盆腔转移放疗者3DCRT以4个射野数计划为优,IMRT以9个射野数计划为优.高剂量范围内IMRT较3DCRT对脊髓及小肠的保护作用明显,IMRT较3DCRT减少了高剂量区直肠、膀胱的受照体积,从而有望减少OAR放射治疗并发症的发生概率.

Abstract：

Objective To compare the differences of target-volume(PTV) coverage and organ at risk (OAR) protection between three dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy(IMRT) for patients with pelvis metastasis of cervical cancer underwent radical hysterectomy and pelvic lymphadenectomy. To explore the optimal treatment methods for pelvis metastasis of cervical cancer.Methods 10 patients with pelvis metastasis of cervical cancer underwent radical hysterectomy and pelvic lymphadenectomy were selected for this study. The images scanned by CT were transferred to treatment planning system to generate 3DCRT and IMRT plans. The impacts of 3DCRT on PTV were compared with those of IMRT. Isodose line and dose volume histograms(DVH) were used to evaluate to the dose-distribution in PTV and OAR. Results For 95 % confidence interval, the margin from CTV to PTV was 1 cm. Conformal indexs (CIs) of PTV for 3, 4, 5 and 6 fields 3DCRT were 0.46, 0.67, 0.68 and 0.68, respectively. When beyond 4 fields, the advantage of adding fields was not significant. CIs of PTV for 5, 7, 9, 11 and 13 fields IMRT were 0.75, 0.83 0.84, 0.85 and 0.85, respectively. When beyond 9 fields, the advantage of adding fields was not significant. The maximum dose of the bowl and spine cord in IMRT plans were lower than that in the 3DCRT plans (P <0.05). Maximum dose of OAR had no significant differences (includingt the bone, recttum and bladder) between IMRT and 3DCRT plans. Conclusion For patients with pelvis metastasis of cervical cancer after radical surgery, 4 fields planning in 3DCRT and 9 fields planning in IMRT are feasible. At high dose levels, the IMRT plans can more significantly protect the bowl and spine cord and decrease the radiation volume of colorectal and urinary bladder at risk than 3DCRT, so IMRT may potentially diminish probability of the normal tissue complications.     

局部晚期宫颈癌CT图像引导下192Ir三维腔内后装治疗剂量体积参数与疗效关系

目的 观察CT图像引导下192Ir三维腔内后装治疗的肿瘤靶区及危及器官受照射体积剂量参数与肿瘤局部控制率及晚期副反应之间关系.方法 10例局部晚期宫颈癌患者在完成盆腔外照射40 Gy及同期化疗后开始每周1次的CT图像引导下192Ir三维腔内后装治疗,每次治疗前进行CT扫描定位,勾画肿瘤靶区(GTV、CTV)和危及器官,利用PLATO治疗计划系统进行逆向治疗计划设计及优化,CTV单次处方剂量为6 Gy,治疗5～7次.结果 1年盆腔控制率为90%,1～2级放射性肠炎发生率为50%,无≥3级副反应.90%CTV等效生物剂量(BED)和相当于2 Gy分次的等效剂量(EQD2)分别为(95.50±7.81)Gy和(79.73±6.57)Gy(α/β=10).90%GTV的BED和EQD2分别为(101.86±7.27)Gy和(84.95±6.1)Gy(α/β=10).90%处方剂量对GTV、CTV的覆盖率分别为92%±4%、87%±7%.直肠、乙状结肠2 cm3体积受到的最小照射剂量分别为(74.97±1.64)、(67.93±4.30)Gy(EQD2,α/β=3).与二维治疗计划相比,三维治疗计划在没有改变A点剂量、直肠参考点剂量情况下提高了GTV、CTV的90%体积受照射剂量及90%处方剂量对GTV、CTV的覆盖率.结论 CT图像引导下192Ir三维腔内后装治疗提高了处方剂量对肿瘤靶区的覆盖率,1年盆腔控制率为90%且无严重副反应,远期疗效观察中.

Abstract：

Objective To investigate the correlation between dose volume histogram(DVH)of tumor targets and organs at risk(OAR)at CT-image based 192Ir brachytherapy and effects and complications for patients with locally advanced cervical cancer. Methods Ten patients with FIGO stage ⅢB cervical cancer received CT image-based 192Ir intracavitary brachytherapy after 54 Gy of three-dimentional four-field pelvic external beam radiotherapy and concurrent weekly cisplatin chemotherapy. Before each brachytherapy,CT images were acquired with applicators in place. Gross tumor volume(GTV), clinical target volume (CTV)and OAR were contoured and inverse treatment planning was designed and optimized by using PLATO treatment planning system. Conventional two-dimensional plans were also designed for comparison.The total intracavitary brachytherapy dose was 30 -42 Gy in 5 -7 fractions. The patients were followed, and the local control and complications were analyzed. The biologically equivalent dose(BED)and biologically equivalent dose in 2 Gy fractions(BED2)for GTV, CTV and OAR were calculated. The minimum dose in the most irradiated tissue volume 2 cm3(D2 cm3)adjacent to the applicator of the sigmoid colon, rectum,bladder and small bowel was determined from the DVH. Results The 1-year local pelvic control rate was 90% and grade 1-2 late complication of sigmoid colon and rectum was 50%. No grade 3 or more complications developed. On CT-image based planning, the BED and BED2 to 90% of the CTV(D90)were 95.50 Gy ± 7. 81 Gy and 79. 73 Gy ± 6. 57 Gy. The BED and BED2 to 90% of the GTV(D90)were 101.86 Gy ± 7.27 Gy and 84. 95 Gy ± 6. 1 Gy. The volume enclosed by 90% of prescribed dose(V90)for GTV and CTV were 92% ±4% and 87% ±7% respectively. The D2cm3 for rectum and sigmoid colon were 74. 97 Gy ±1.64 Gy and 67. 93 Gy ± 4. 30 Gy(EQD2, α/β = 3). Comparing with 2D brachytherapy plans , CT - image based planning has improved D90 and V90 for GTV and CTV with similar dose at point A and rectum reference point. Conclusions Computer tomography-image based 192Ir brachytherapy has resulted in the better dose distribution to the tumor targets with excellent tumor control and acceptable toxicity.     

肺部小肿瘤γ刀照射与三维适形及调强放疗计划的剂量学比较

目的 对肺部小肿瘤的γ刀照射计划与三维适形、调强放疗计划进行剂量学比较,评估其优缺点.方法 选择14例肺部小肿瘤患者分别做γ刀照射计划(计划1)及5个野三维适形(计划2)、调强放疗计划(计划3),使计划靶体积(PTV)与95%PTV的剂量一致,分析各计划PTV的适形指数(CI)、均匀指数(HI),肺接受5～30 Gy照射体积占全肺体积百分比(V5、V10、V20、V30),以及食管及脊髓最大受照剂量.3个计划间两两比较采用配对t检验.结果 1、2、3计划的CI值分别为0.58、0.46、0.63[计划1＞计划2(t=-3.95,P=0.000),计划3＞计划2(t=-6.01,P=0.000),计划1=计划3(t=1.64,P=0.116)];HI值分别为1.66、1.10、1.07[计划1＞计划2、计划1＞计划3(t=-20.52、21.41,P均=0.000),计划2=计划3(t=-1.08,P=0.294)].双肺V5、V10、V20、V30在计划1中均最小(10.0%、5.6%、2.4%、1.2%),计划3次之(20.2%、13.4%、6.9%、3.0%),计划2最大(26.5%、18.0%、11.4%、4.6%);计划1＜计划2(t=9.68、8.41、5.45、5.14,P均=0.000),计划1＜计划3(t=7.58、8.95、6.15、4.78,P均=0.000),计划2＞计划3(t=9.71、5.91、4.13、3.91,P均=0.000).计划1、2、3的食管最大受量分别为(24.93±21.54)、(31.90±18.75)、(29.19±23.09)Gy,计划1＜计划2(t=-2.71,P=0.013)、计划1=计划3(t=-1.49,P=0.152),计划2=计划3(t=1.35,P=0.193);脊髓最大受量分别为(12.07±10.67)、(17.70±11.35)、(8.92±10.04)Gy,计划2＞计划1＞计划3(t=-2.38、2.29、4.83,P=0.1027、0.033、0.000);每个病灶的3个计划均满足食管最大剂量≤60 Gy、脊髓最大剂量≤40 Gy要求.结论 肺部小肿瘤γ刀照射计划与三维适形、调强放疗计划比较,其对肺的损伤最小,但靶区均匀性较差、脊髓最大受量较调强放疗计划高.

Abstract：

Objective To compare dose distribution in gamma knife radiotherapy plan, conformal radiotherapy(CRT)plan and intensity modulated radiotherapy(MRT)plan for patients with small mass in lung, and evaluate their characters. Methods Fourteen patients with small mass in lung participated in the study. Gamma knife radiotherapy plan(plan 1), CRT plan(plan 2)and IMRT plan(plan 3)were made for each mass. The planning target volume(PTV)and the dose include 95% PTV were consistent.Conformal index(CI), homogeneity index(HI), lung V5 ,V10 ,V20 ,V30 and the max dose of esophagus and spinal cord were analyzed. Paired samples t-test was used for comparison between each two plans. Results The CI of the plan 1,2 and 3 were 0. 58,0. 46 and 0. 63, respectively. CI of the plan 1 ＞ that of the plan 2 (t= -3.95,P =0.000),plan 3 ＞ plan 2(t = -6.01 ,P =0.000),plan 1 =plan 3(t =1.64,P =0.116);HI of the plan 1,2 and 3 were 1.66,1.10 and 1.07 respectively. HI of the plan 1 ＞ plan 2 ,plan 1 ＞ plan 3(t= -20.52,21.41 respectively, both P=0. 000),plan 2 = plan 3(t= -1.08,P=0.294). The wholelung V5 ,V10 ,V20 and V30 were 10.0% ,5.6% ,2. 4% and 1.2%, respectively, in plan 1 ;20. 2% ,13. 4%,6. 9% ,3.0%, respectively, in plan 3; and 26. 5%, 18. 0%, 11.4% and 4. 6%, respectively, in plan 2.The V5, V10, V20 and V 30 of the plan 1 ＜ in plan 2(t = 9. 68,8. 41,5. 45,5. 14, all P = 0. 000), the V5,V10,V20 and V30 of the plan 1 ＜ in plan 3(t=7.58,8.95,6. 15,4.78, respectively, all P=0.000),the V5 ,V10, V20andV30 oftheplan2 ＞ inplan3(t =9. 71,5. 91,4. 13,3.91, respectively, allP =0.000).The max dose of esophagus in plan 1 ,2 and 3 were 24.93 ± 21.54, 31.90 ± 18. 75, 29. 19 ± 23.09 Gy,respectively, plan 1 ＜ plan 2(t = -2. 71 ,P=0.013),plan 1 = plan 3(t = - 1.49,P =0. 152),plan 2 =plan 3(t = 1.35, P = 0. 193). The max dose of spinal cord in plan 1,2 and 3 were 12.07 ± 10. 67,17.70 ±11.35 and 8.92 :± 10. 04 Gy, respectively, plan 2 ＞ plan 1 ＞plan 3(t = -2. 38,2. 29,4. 83,P=0. 1027,0.033,0.000);All three plans of each mass meet the needs that the max dose of the esophagus≤60 Gy and the max dose of spinal cord ≤40 Gy. Conclusions The dose of the normal lung was lower, but the HI and the max dose of spinal cord were higher in Gamma knife radiotherapy plan than those in the CRT and the IMRT plan of the small mass in lung.     

Dosimetric analysis of tomotherapy-based intensity-modulated radiotherapy with and without bone marrow sparing for the treatment of cervical cancer

Objective The aim of the study was to compare tomotherapy-based bone marrow-sparing intensity-modulated radiotherapy(BMS-IMRT) with intensity-modulated radiotherapy(IMRT) without entering the pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods BMS-IMRT and IMRT plans were designed for a cohort of nine patients. The prescribed dose was 45 Gy in 1.8 Gy daily fractions, and 95% of the planned target volume received this dose. The doses were computed using a commercially available treatment planning system with the convolution/superposition algorithm. Plans were compared according to dose-volume histogram analysis in terms of planning target volume homogeneity and conformity indices(HI and CI) as well as organ at risk dose and volume parameters. Results BMS-IMRT had advantages over IMRT in terms of CI, but was equivalent to the latter in HI. V5, V10, V20, V30, and V40 of pelvic bone marrow in BMS-IMRT decreased by 0.06%, 17.33%, 22.19%, 13.85%, and 16.46%, respectively, compared with IMRT. Except for V30 of the small bowel and V30 and V40 of the bladder, no statistically significant differences were found between BMS-IMRT and IMRT in the small bowel, bladder, and rectum. Conclusion For cervical cancer patients receiving tomotherapy-based radiotherapy after hysterectomy, BMS-IMRT reduced pelvic bone marrow volume receiving low-dose radiation, and it may be conducive to preventing acute hematologic toxicity.     

儿科患者的同时整和加量调强放射治疗:对两个商业治疗计划系统的评价(英文)

Objective: The aim of the work was to compare the dosimetric results that were obtained by using two treatment planning systems (TPS) Siemens KonRad version 2.2.23, Elekta XiO version 4.4 to perform a simultaneous integrated boost (SIB) for head and neck and central nervous system (CNS) cases in paediatric patients. Methods: The CT scan data for five paediatric patients, with head and neck and CNS tumors, were transferred into both of the TPSs. Clinical step-and-shoot intensity-modulated radiotherapy (IMRT) treatment plans were designed using 6 MV photon beam for delivery on a Siemens Oncor Accelerator with multileaf collimator MLC (82 leaf). Plans were optimized to achieve the same clinical objectives using the same beam energy, number and direction of beams. The analysis was based on isodose distributions, the dose volume histogram (DVH) for planning target volume (PTV) and the relevant organs at risk (OARs) as well as volume receiving 2 Gy and 5 Gy, also total number of segments, MU/segment, and the number of MU/cGy had been investigated. Treatment delivery time and conformation number were two other parameters in this study. Results: The segmentation using KonRad was more efficient, resulting in fewer segments (reduction between 13.2% and 48.3%), fewer MUs (reduction between 10.7% and 33%) and that reflected on treatment delivery times to be shorter by up to 8 min or 46%. In most of the cases KonRad had the highest volume receiving in excess of 2 and 5 Gy, and XiO showed the lowest. Also KonRad achieved slightly better conformality (0.76±0.054) than XiO (0.73±0.05) while XiO presented a higher modulation factor value (3.3 MU/cGy) than KonRad (2.4 MU/cGy). Conclusion: The KonRad treatment planning system was found to be superior to the XiO treatment planning system. This is true for the possible increase of radiation-induced secondary malignancies as well as for the local control.     

加速器模型和治疗计划系统对知识库计划模型的影响：一项基于宫颈癌适形调强放射放疗计划的研究

背景与目的：“RapidPlan”利用适形调强放射治疗（intensity-modulated radiotherapy,IMRT）中的患者解剖和剂量信息,以剂量体积直方图（dose-volume histogram,DVH）预测模型的方式来预测新计划的剂量分布。针对每种治疗计划系统（treatment planning system,TPS）和治疗机器模型分别建立知识库模型需耗费大量精力且选择繁琐,因此本研究评估基于特定TPS和加速器模型建立的知识库计划模型能否适用于其他TPS和加速器模型。方法：选取2015—2016年于复旦大学附属肿瘤医院采用IMRT技术治疗的50例临床治疗的宫颈癌患者的放疗资料,使用RapidPlan建立基于知识库的计划预测模型。训练数据均基于Pinnacle计划系统,机器模型采用Synergy加速器6 MV光子射线。使用该预测模型对15例宫颈癌病例进行预测,提取目标函数数值后,分别在3组不同的优化环境中重新优化以评估加速器模型和TPS对知识库计划模型的影响：① 与模型构建一致的TPS和加速器模型,即Pinnacle与Synergy;② TPS一致但加速器模型不一致,即Pinnacle与Truebeam;③ TPS和加速器模型都不一致,即Eclipse和Truebeam。评估方法为基于知识库模型生成的计划与相应环境下人工计划进行剂量学比较。结果：组2和组3中,知识库计划与人工计划得到相似质量的计划靶区（planning target volume,PTV）剂量覆盖,而在组1中知识库计划改善了PTV的D ₂ %（0.95 Gy,P<0.01）和剂量均一性指数（homogeneity index,HI）(0.02,P<0.01）。知识库计划降低了所有3组计划的膀胱V ₃₀ 、V ₄₅ 和平均剂量,同时知识库计划还降低了肠道的平均剂量。结论：基于知识库的计划模型对加速器和TPS的依赖并不显著。     

Can All Centers Plan Intensity-Modulated Radiotherapy (IMRT) Effectively? An External Audit of Dosimetric Comparisons Between Three-Dimensional Conformal Radiotherapy and IMRT for Adjuvant Chemoradiation for Gastric Cancer

PURPOSE: To compare dosimetric endpoints between three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) at our center with limited IMRT experience, and to perform an external audit of the IMRT plans. METHODS AND MATERIALS: Ten patients, who received adjuvant chemoradiation for gastric cancer, formed the study cohort. For standardization, the planning target volume (PTV) and organs at risk were recontoured with the assistance of a study protocol radiologic atlas. The cohort was replanned with CMS Xio to generate coplanar 3D-CRT and IMRT plans. All 10 datasets, including volumes but without the plans (i.e., blinded), were transmitted to an experienced center where IMRT plans were designed using Nomos Corvus (IMRT-C) and ADAC Pinnacle (IMRT-P). All IMRT plans were normalized to D95% receiving 45 Gy. RESULTS: Intensity-modulated radiotherapy yielded higher PTV V45 (volume that receives > or = 45 Gy) (p < 0.001) than 3D-CRT. No difference in V20 was seen in the right (p = 0.9) and left (p = 0.3) kidneys, but the liver mean dose (p < 0.001) was superior with IMRT. For the external audit, IMRT-C (p = 0.002) and IMRT-P (p < 0.001) achieved significantly lower left kidney V20 than IMRT, and IMRT-P (p < 0.001) achieved lower right kidney V20 than IMRT. The IMRT-C (p = 0.003) but not IMRT-P (p = 0.6) had lower liver mean doses than IMRT. CONCLUSIONS: At our institution with early IMRT experience, IMRT improved PTV dose coverage and liver doses but not kidney doses. An external audit of IMRT plans showed that an experienced center can yield superior IMRT plans.     

两套TPS之间VMAT计划优化质量评价研究

目的 探讨两套商用TPS实施VMAT优化的性能特点。方法 随机选取本院宫颈癌和前列腺癌患者各10例,分别利用瓦里安Eclipse和飞利浦Pinnacle TPS设计VMAT计划(宫颈癌2Arc、3Arc,前列腺癌1Arc、2Arc),采用瓦里安Clinac iX加速器配备RapidArc技术实施照射。从剂量分布、实施效率、治疗照射参数等方面评价治疗计划质量的差异。对组间比较行配对t检验。     

Dosimetric verification for intensity-modulated radiotherapy of thoracic cancers using experimental and Monte Carlo approaches

PURPOSE: To investigate the dosimetric accuracy of commercial treatment planning systems used in intensity-modulated radiotherapy (IMRT) for thoracic cancer. METHODS AND MATERIALS: Clinical IMRT plans for lung and esophageal cancers and mesothelioma were used to investigate the accuracy of dose calculations from two commercial treatment planning systems (Pinnacle and Corvus systems). Dose distributions were measured with ion chambers and thermoluminescent dosimeters for individual IMRT fields and composite treatment plans in water phantoms and anthropomorphic phantoms. A Monte Carlo-based system was established to compute three-dimensional dose distributions to compare with the treatment planning system calculations. RESULTS: Dose calculations from the Pinnacle system were acceptable within 5% of the local dose or a 5-mm distance-to-agreement for 80% of the points measured with ion chambers, 74% of the points measured with thermoluminescent dosimeters, and 96% of the points compared with the Monte Carlo calculations. For the Corvus system, 89% of the points agreed with the measured dose and 98% agreed with the Monte Carlo calculations. Underestimation of the dose from the treatment planning system was found in the low-dose regions (<50% of the prescribed dose), possibly caused by inadequate modeling of the multileaf collimators. CONCLUSION: The Pinnacle and Corvus dose calculations were acceptable for thoracic IMRT in high-dose regions. Beam modeling is likely the most critical factor for the accuracy of IMRT dose calculations.     

Significant improvement in normal tissue sparing and target coverage for head and neck cancer by means of helical tomotherapy.

PURPOSE: In order to explore the potential of helical Tomotherapy in the treatment of head and neck cancers (HNC), a planning study comparing our routinely delivered IMRT technique (dynamic MLC Varian 600CD Linac, inversely optimised by the Helios/Eclipse system) against two different Tomotherapy planning approaches was performed. MATERIALS AND METHODS: In the first Tomotherapy plan (TOMO-a), we merely applied the same constraints used for the IMRT-Linac technique; in the second one (TOMO-b), we tried to stress the sparing of parotids and mandible while keeping PTV coverage and spinal cord Dmax similar to their values in the TOMO-a plan. Five patients with locally advanced oropharinx (n=3), hypopharinx (n=1) and larynx (n=1) cancer were considered. For each patient, CTV1 including neck nodes and the tumour was defined and was expanded with a margin of 0.5 cm (PTV1); then, CTV2 including high risk nodes and CTV3 including only T were defined and the corresponding PTV2/PTV3 were defined by a 0.5 cm expansion. IMRT and Tomotherapy planning were optimised to deliver 54 Gy in 30 fractions on PTV1 and 16.2 Gy in 9 fractions on PTV3; in the case a PTV2 was defined, 15 Gy were concomitantly delivered while delivering 16.2 Gy on PTV3. Separated plans for the two phases (Phase 1: first 30 fractions; Phase 2: last 9 fractions) were compared in terms of dose-volume histograms (DVH) and dose statistics on PTVs and OARs. RESULTS: When considering Phase 1, Tomotherapy improved the homogeneity of the dose distribution within PTV1 while delivering the same prescribed dose (assessed to be the median dose to PTV): the fraction of PTV1 receiving more than 95% of the prescribed dose (V95%) increased from 90% (IMRT) to 96-97% for Tomotherapy plans. Dmax within PTV1 decreased from 60.3 Gy (IMRT) to 57.4 Gy (TOMO-a) and 58.7 Gy (TOMO-b). Spinal cord Dmax decreased from 31.6 Gy (IMRT) to 26.5 Gy (TOMO-a) and 24.6 Gy (TOMO-b). No attempts to further reduce spinal cord Dmax were done. Mean dose to the parotids decreased from 26.1 Gy (IMRT) to 25.1 Gy (TOMO-a) and 20.8 Gy (TOMO-b). Mandible was significantly better spared with Tomotherapy: mean dose decreased from 34.9 Gy (IMRT) to 34.0 Gy (TOMO-a) and 30.7 Gy (TOMO-b).When considering phase 2, the average gains (TOMO-b vs IMRT) were more modest and depended on the location of PTV2/PTV3. CONCLUSIONS: Preliminary findings obtained in a sequential approach for HNC suggest that Tomotherapy has the potential to significantly improve the therapeutic ratio with respect to a conventional IMRT delivery method.     

动态调强和静态调强技术治疗中晚期宫颈癌剂量学比较

目的宫颈癌严重威胁着妇女的健康,调强放射治疗(intensity modulated radiotherapy,IMRT)联合后装放疗成为中晚期(ⅡB~ⅢB期)宫颈癌治疗的主要方法。本研究旨在比较动态调强放射治疗(dynamic intensity modulated radiotherapy,dIMRT)技术和强度等级不同的静态调强放射治疗(static intensity modulated radiotherapy,sIMRT)技术治疗中晚期宫颈癌时的剂量学特点,为临床应用提供参考。方法回顾性选取玉林市红十字会医院2017-10-09-2019-03-24收治的中晚期(ⅡB~ⅢB期)宫颈癌患者50例(其中ⅡB期17例,ⅢA期15例,ⅢB期18例),在增强定位CT影像上勾画靶区和危及器官。在Eclipse 10.0计划系统中基于同一套CT图像设计5野调强计划,选取dIMRT技术中的滑窗技术(Sliding Window,SW)和强度等级分别为13(Ec13),10(Ec10),7(Ec7)和5(Ec5)的sIMRT技术,处方剂量均为50Gy/25次,要求计划靶区95%的体积达到处方剂量。通过分析剂量-体积直方图(dose volume histogram,DVH)及传输参数,比较5种调强放射治疗方式中计划靶区的靶区适形指数(conformity index,CI)、均匀指数(homogeneity index,HI)、危及器官(膀胱、小肠和直肠)剂量分布和机器参数的差异。数据经Shapiro-Wilk法检验符合正态分布后,组间均值差异进行单因素方差分析,两两多重比较采用LSD法。用Pearson法分析sIMRT强度等级与子野数量的关系。结果5种计划的靶区最大剂量Dmax、平均剂量Dmean、HI值和CI值差异有统计学意义。其中,对于SW、Ec13、Ec10、Ec7和Ec5计划,Dmax值分别为(55.27±1.29)、(55.54±1.18)、(55.83±1.10)、(57.51±1.05)和(59.90±1.08)Gy,差异有统计学意义,F=154.844,P<0.01;HI值分别为1.06±0.01、1.06±0.01、1.07±0.01、1.09±0.01和1.12±0.02,差异有统计学意义,F=452.442,P<0.01;CI值分别为0.89±0.01、0.88±0.01、0.88±0.01、0.86±0.01和0.83±0.01,差异有统计学意义,F=107.928,P<0.01。相对于sIMRT,SW组的Dmean、HI值和CI值差异有统计学意义,均P<0.05。对于膀胱、小肠和直肠,5组计划中剂量体积V20、V30和V40差异无统计学意义,而最大剂量Dmax则差异有统计学意义,均P<0.01。Ec5计划中膀胱、小肠和直肠V50值的均值比SW计划中均值分别为13.58%、45.14%和36.20%。SW计划中传输时间为(6.82±0.55)min,机器跳数(monitor units,MUs)为(1090.9±88.7)MUs,比sIMRT技术数值大,差异有统计学意义,均P<0.01。对于sIMRT,强度等级越高,子野数量越多,治疗的实施时间越长。子野数量与强度等级呈线性关系。结论对于中晚期宫颈癌,dIMRT技术与强度等级≥10的sIMRT技术剂量分布相当。综合考虑,临床应用中优先选取dIMRT或者强度等级等于或接近于10的sIMRT。     

IMRT for breast. a planning study.

BACKGROUND AND PURPOSE: To evaluate the performance of ten different treatment-planning systems when intensity modulated (IMRT) plans are designed for breast treatments that include the irradiation of the internal mammary chain. PATIENTS AND METHODS: A dataset of five patients (CT images and volumes of interest) was distributed to design IMRT plans on the ten systems. To minimise biases, the same geometry and clinical planning aims were imposed on the individual plans. Results were analysed in terms of dose distributions and dose volume histograms. RESULTS AND CONCLUSIONS: For target coverage, the volume receiving more than 95% of the prescribed dose ranged from 77% (OTP) to 91% (Eclipse and Pinnacle), the volume receiving more than 107% ranged from 3.3% (Hyperion) to 23.2% (OTP). The mean dose to ipsilateral lung ranged from 13 Gy (Eclipse) to 18 Gy (OTP). The volume of the contralateral breast receiving more than 10 Gy ranged from 3% (Pinnacle) to 26% (Precise). The volume of heart receiving more than 20 Gy ranged from 7% (Eclipse) to 47% (Precise), the maximum significant dose to heart ranged from approximately 27 Gy (XiO) to approximately 49 Gy (Precise). The maximum significant dose to healthy tissue ranged from approximately 51 Gy (Eclipse) to approximately 62 Gy (OTP). It was also possible to show that the treatment geometry proposed here enables to minimise contralateral breast irradiation while keeping minimal ipsilateral lung (or heart) involvement and satisfactory target coverage.     

On the performances of different IMRT treatment planning systems for selected paediatric cases

Background

To evaluate the performance of seven different TPS (Treatment Planning Systems: Corvus, Eclipse, Hyperion, KonRad, Oncentra Masterplan, Pinnacle and PrecisePLAN) when intensity modulated (IMRT) plans are designed for paediatric tumours.

Methods

Datasets (CT images and volumes of interest) of four patients were used to design IMRT plans. The tumour types were: one extraosseous, intrathoracic Ewing Sarcoma; one mediastinal Rhabdomyosarcoma; one metastatic Rhabdomyosarcoma of the anus; one Wilm's tumour of the left kidney with multiple liver metastases. Prescribed doses ranged from 18 to 54.4 Gy. To minimise variability, the same beam geometry and clinical goals were imposed on all systems for every patient. Results were analysed in terms of dose distributions and dose volume histograms.

Results

For all patients, IMRT plans lead to acceptable treatments in terms of conformal avoidance since most of the dose objectives for Organs At Risk (OARs) were met, and the Conformity Index (averaged over all TPS and patients) ranged from 1.14 to 1.58 on primary target volumes and from 1.07 to 1.37 on boost volumes. The healthy tissue involvement was measured in terms of several parameters, and the average mean dose ranged from 4.6 to 13.7 Gy. A global scoring method was developed to evaluate plans according to their degree of success in meeting dose objectives (lower scores are better than higher ones). For OARs the range of scores was between 0.75 ± 0.15 (Eclipse) to 0.92 ± 0.18 (Pinnacle³ with physical optimisation). For target volumes, the score ranged from 0.05 ± 0.05 (Pinnacle³ with physical optimisation) to 0.16 ± 0.07 (Corvus).

Conclusion

A set of complex paediatric cases presented a variety of individual treatment planning challenges. Despite the large spread of results, inverse planning systems offer promising results for IMRT delivery, hence widening the treatment strategies for this very sensitive class of patients.     

宫颈癌根治术后降低骨髓剂量的调强放疗剂量学研究

目的 通过对宫颈癌根治术后全盆腔常规放疗(CRT)与调强放疗(IMRT)的对比研究,比较应用不同放疗技术在处方剂量45.0、50.4 Gy时降低髂骨骨髓受照体积和剂量.方法 选择FIGO分期ⅠA～ⅡB期17例宫颈癌根治术后患者,CTV范围包括阴道顶部、宫旁、骶前区域、部分髂总及盆腔淋巴结,CTV外放1 cm(后方紧邻直肠后放0.5 cm)产生PTV.应用ADAC Pinnacle3 Version7.4f治疗计划系统分别设计3种照射技术:CRT前后两野对穿(CRT2f)、CRT前后两野+两侧野(CRT4f)、调强7个野(IMRT7f).处方剂量分别为45.0、50.4 Gy,治疗计划优化后确保≥97%PTV接受≥95%处方剂量,应用剂量体积直方图获得不同治疗方法 髂骨骨髓的V20、V24、V30、V40.结果 处方剂量为45.0 Gy时右和左髂骨骨髓IMRT7f、CRT2f及CRT4f计划的V25分别为45.04%和40.90%、64.37%和65.25%及60.20%和61.42%(H=7.45,P=0.024和H=6.62,P=0.038),V30为36.91%和22.21%、52.69%和48.80%及40.52%和42.33%(H=7.91,P=0.019和H=10.5,P=0.005),V40为23.83%和19.65%、51.85%和46.11%及37.97%和35.30%(H=17.14,P=0.000和H=20.71.P=0.000);处方剂量为50.4 Gy时,分别为52.43%和50.06%、65.89%和67.75%及69.56%和64.23%(H=6.29,P=0.043和H=6.37,P=0.041),38.91%和31.93%、54.96%和51.29%及52.18%和47.57%(H=6.91,P=0.031和H=15.19,P=0.000),25.93%和20.87%、53.30%和49.83%及44.26%和37.77%(H=16.71,P=0.000和H=20.78,P=0.000).结论 与CRT相比IMRT技术能产生理想的靶区剂茸分布并由此降低髂骨骨髓受照体积和剂量.