Simultaneous modulated accelerated radiation therapy for esophageal cancer:A feasibility study

AIM: To establish the feasibility of simultaneous modulated accelerated radiation therapy (SMART) in esophageal cancer (EC).

Clinical observation of gemcitabine and concomitant three-dimensional conformal radiotherapy in the treatment of locally advanced non-small cell lung cancer

Objective： To evaluate the clinical effect of gemcitabine and concurrent three-dimensional conformal radiation therapy （3D-CRT） for locally advanced non-small cell lung cancer （NSCLC）. Methods： From April 2002 to June 2005, 38 patients with inoperable stage Ⅲ NSCLC were treated with gemcitabine and 3D-CRT simultaneously. Chemotherapy consisted of intravenously gemcitabine 350 mg/m^2 on days 1, 8, 15, 22, 29, 36.3D-CRT was delivered up to a total dose of 60-64 Gy with a 2.0 Gy dose fraction per day, 5 days per week. Results： The overall response rates of primary tumor and mediastinum metastatic node were 86.8% （33/38） and 90.6% （29/32） respectively, and 91.7% （22/24） and 78.6% （11/14） for squamous cell carcinoma and adenocarcinoma respectively. The acute side effects of patients were mostly myelosuppression, nausea, vomiting, radiation-induced esophagitis and pneumonitis （RTOG 1/11）, however, all of them were cured. Conclusion： Concurrent application of gemcitabine and 3D-CRT can improve the overall response rate for locally advanced NSCLC without aggravating the side effects.

Study of the impact of CT/CT image fusion radiotherapy on V_(20) and radiation pneumonitis of non-small cell lung cancer

Objective:The aim of our study was to investigate the value of CT/CT image fusion radiation treatment planning in non-small cell lung cancer(NSCLC) and the impact on V20 and radiation pneumonitis(RP).Methods:Patients who were pathologically or cytologically diagnosed of stage IIIA and IIIB NSCLC were treated with three-dimensional conformal radiation therapy(4000 cGy).Forty patients got at least 25% tumor reduction were randomly divided into two groups:group A of regular shrink field radiotherapy(20 cases) and group B of CT/CT image fused shrink field radiotherapy(20 cases).Dosage reached 6600 cGy.Clinical data,V20 and RP were observed within 3 months after radiotherapy.Statistical analysis was conducted for the NSCLC patients.Results:22.5%(9/40) patients got RP during follow-up.Group A accounted for 6 cases(30%),and group B had 3 cases(15%).There was no marked difference between the two groups(P = 0.256),univariate analysis revealed that the IV20 of A and B groups,and IV20 and CV20 of all patients were statistically related to the incidence of RP(P < 0.05).With Wilcoxon method assay,the ipsilateral lung V20 and contralateral lung V20 had statistical significance between the two groups(P < 0.05).Conclusion:The CT/CT image infusion treatment planning could increase the radical dosage with better tumor control probability but won't increase adverse reaction.

Influences of Motion Artifacts on Three-Dimensional Reconstruction Volume and Conformal Radiotherapy Planning

Objective ：To investigate the influences of motion artifacts on three-dimensional （3D） reconstruction volume and conformal radiotherapy planning. Methods： A phantom which can mimic the clip motion of lung tumor along the cranial-caudal direction is constructed by step motor, small ball of polyethylene and potato. Ten different scan protocols were set and CT data of the phantom were acquired by using a commercial GE LightSpeedl6 CT scanner. The 3D reconstruction of the CT data was implemented by adopting volume-rendering technology of GE AdvantageSim 6.0 system. The reconstructed volumes of each target in different scan protocols were measured through 3D measuring tools. Thus, relative deviations of the reconstruction volumes between moving targets and static ones were determined. The three-dimensional conformal radiation therapy （3D- CRT） plans and conformal fields were created and compared for a static/moving target with the WiMRT treatment planning system （TPS）. Results：For a static target, there was no obvious difference among the 3D reconstruction volumes when the CT data were acquired with different pitches and slices. The appearance of 3D reconstruction volume and 3D conformal field of a moving target was quite different from that of static one. The maximum relative deviation is nearly 90% for a moving target scanned with different scan protocols. The relative deviations are variable among the different targets, about from -39.8% to 89.5% for a smaller target and from - 18.4% to 20.5% for a larger one. Conclusion ：The motion artifacts have great effects on 3 D-CRT planning and reconstruction volume, which will greatly induce distorted conformal radiation fields and false DVHs for a moving target.

The Effect of Absorbed Dose to Organs at Risk Following Craniospinal Irradiation Using Different Radiotherapy Techniques

Introduction: In medulloblastoma patients craniospinal irradiation is an important element the treatment. Our study aimed to evaluate the effect of absorbed dose to organs at risk using the hybrid intensity-modulated radiation therapy (IMRT) versus three-dimensional conformal radiotherapy (3DCRT) for craniospinal irradiation (CSI) in average risk medulloblastoma patients. Materials and Methods: In this study, thirteen medulloblastoma patients were included. The prescribed total dose to the planning target volume (PTV) was 23, 40 Gy in 13 fractions. Two radiotherapy techniques, three dimensional conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (IMRT) were used to treat these patients. The coverage of the Target was evaluated using the D mean, D95%, D2%, D98% and V95%. Other parameters were also compared such as Integral dose (ID), Homogeneity index (HI) and doses to the organs at risk (OARs). Results: There was no significant difference in the mean dose received by the PTV-Brain or the dose received by 95% and 98% of PTV volume using the two techniques. For PTV-Spine, the percentage volume receiving 95% of the total dose increased significantly in the hybrid IMRT technique compared to the conformal technique. So, hybrid IMRT plan achieved the best coverage for PTV spine. Lower dose for OAR was delivered by 3DCRT, except the heart and thyroid, hybrid IMRT achieved better sparing. All plans resulted in the same dose homogeneity index (DHI) for PTV-Brain. For PTV-Spine, hybrid IMRT technique achieved better dose homogeneity compared to 3DCRT technique (1.09 vs. 1.12;p > 0.05). Conclusions: hybrid IMRT technique can be realized on conformal technique because it achieved better dose coverage for the (PTV) and organ at risk (OAR). 3DCRT reduced mean dose to most OARS, except the heart and thyroid. Therefore, the hybrid IMRT technique may be a CSI treatment alternative to 3DCRT.

Helical tomotherapy and volumetric modulated arc therapy:New therapeutic arms in the breast cancer radiotherapy

AIM To analyse clinical and dosimetric results of helical tomotherapy(HT) and volumetric modulated arc therapy(VMAT) in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT). Dose were 63.8 Gy(HT) and 63.2 Gy(VMAT) in the tumour bed, 52.2 Gy in the breast, 50.4 Gy in supraclavicular nodes(SCN) and internal mammary chain(IMC) with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions. Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort, the coverage of clinical target volumes was as follows: Tumour bed: 99.4% ± 2.4%; breast: 98.4% ± 4.3%; SCN: 99.5% ± 1.2%; IMC:96.5% ± 13.9%. For the VMAT cohort, the coverage was as follows: Tumour bed: 99.7% ± 0.5%, breast: 99.3% ± 0.7%; SCN: 99.6% ± 1.4%; IMC: 99.3% ± 3%. For ipsilateral lung, Dmean and V20 were 13.6 ± 1.2 Gy, 21.1% ± 5%(HT) and 13.6 ± 1.4 Gy, 20.1% ± 3.2%(VMAT). Dmean and V30 of the heart were 7.4 ± 1.4 Gy, 1% ± 1%(HT) and 10.3 ± 4.2 Gy, 2.5% ± 3.9%(VMAT). For controlateral breast Dmean was 3.6 ± 0.2 Gy(HT) and 4.6 ± 0.9 Gy(VMAT). Acute skin toxicity grade 3 was 5% in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance. A longer follow-up is needed to assess the impact of low doses to healthy tissues.

Comparison of Dosiology between Three Dimensional Conformal and Intensity-modulated Radiotherapies (5 and 7 fields) in Gastric Cancer Post-surgery

The purpose of this study was to compare the dose distribution of intensity-modulated ra- diotherapy （IMRT） in 7 and 5 fields as well as 3-D conformal radiotherapy （3D-CRT） plans for gastric cancer using dosimetric analysis. In 15 patients with gastric cancer after D1 resection, dosimetric pa- rameters for IMRT （7 and 5 fields） and 3D-CRT were calculated with a total dose of 45 Gy （1.8 Gy/day） These parameters included the conformal index （CI）, homogeneity index （HI）, maximum dose spot for the planned target volume （PTV）, dose-volume histogram （DVH） and dose distribution in the organs at risk （OAR）, mean dose （Dmean）, maximal dose （Dmax） in the spinal cord, percentage of the normal liver volume receiving more than 30 Gy （V30） and percentage of the normal kidney volume receiving more than 20 Gy （V20）. IMRT （7 and 5 fields） and 3D-CRT achieved the PTV coverage. However, IMRT presented significantly higher CI and HI values and lower maximum dose spot distribution than 3D-CRT （P=0.001）. For dose distribution of OAR, IMRT had a significantly lower Dmean and Dmax in spinal cord than 3D-CRT （P=-0.009）. There was no obvious difference in V30 of liver and V20 of kidney between IMRT and 3D-CRT, but 5-field IMRT showed lower Dmean in the normal liver than other two plans （P=0.001）. IMRT revealed favorable tumor coverage as compared to 3D-CRT and IMRT plans. Specifically, 5-field IMRT plan was superior to 3D-CRT in protecting the spinal cord and liver, but this superiority was not observed in the kidney. Further studies are needed to compare differences among the three approaches.

The impact of intensity modulated radiotherapy on the skin dose for deep seated tumors

Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatment planning system. Methods: More investigations for the influences of IMRT on skin doses would increase its applications for many treatment sites. Measuring skin doses in real treatment situations would reduce the uncertainty of skin dose prediction. In this work a pediatric human phantom was covered by a layer of 1 mm bolus at three treatment sites and thermoluminescent dosimeter (TLD) chips were inserted into the bolus at each treatment site before CT scan. Two different treatment plans [three-dimensional conformal radiation therapy (3DCRT) and IMRT] for each treatment sites were performed on XIO 4.04 treatment planning system using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in IMRT by 1.6%, 2.5% and 3.2% for brain, abdomen and pelvis sites respectively. There was good agreement between measured and calculated surface doses, where the calculated surface dose was 15.5% for brain tumor calculated with 3DCRT whereas the measured surface dose was 12.1%. For abdomen site the calculated surface dose for IMRT treatment plan was 16.5% whereas the measured surface dose was 12.6%. Conclusion: The skin dose in IMRT for deep seated tumors is lower than that in 3DCRT which is another advantage for the IMRT. The TLD readings showed that the difference between the calculated and measured point dose is negligible. The superposition calculation algorism of the XIO 4.04 treatment planning system modeled the superficial dose well.

食管癌常规放疗与三维适形放疗剂量分布的比较

目的比较食管癌常规三野照射和三维适形放射治疗2种不同的治疗方法,不同设野方法的计划中靶区及正常组织的受量。方法应用三维治疗计划系统(TPS)在28例食管癌患者的CT虚拟图像上分别设计2种外照射计划(A:常规三野;B:三维适形三野),应用剂量体积直方图比较2种计划肺、心脏等正常组织受量及肺正常组织并发症发生概率(NTCP)的区别。根据肺的NTCP来估计放射性肺炎的发生概率。结果常规三野照射和适形放射治疗的比较:PTV各项指标无显著性差异,心脏受照的体积百分比(V40、V50)及左右肺及双肺受照的体积百分比(V20、V30)等有明显的差异(P=0)。结论食管癌三野常规照射与适形放射治疗比较:三野的适形放射治疗有利于保护心脏及正常肺组织,可降低放射性肺炎的发生概率。

鼻咽癌三维适形放射治疗中质量控制的分析

目的:分析鼻咽癌三维适形放射治疗中的质量控制。方法:使用BJ-66MV单光子直线加速器,STAR-2000三维治疗计划系统和定位头架对鼻咽癌患者行放射治疗。结果:使用面罩固定方式固定体位,采用2mm层厚、2mm层距的CT扫描,获取靶区及其周围组织的三维数据,并设计三维适形放疗计划。在加速器上通过摆位将靶区置于等中心实施放射治疗。结论:鼻咽癌所处部位特殊,临近很多关键器官,因此在三维适形放疗中,必须对CT定位和治疗摆位的过程进行严格的质量控制,保证较小的靶体积给予有效和安全的剂量照射,同时避免对周围重要器官的过量照射,减少并发症的发生。

PET影像在高龄非小细胞肺癌适形放射治疗中应用

目的分析应用胸部18FDG-PET影像对高龄非小细胞肺癌实施三维适形放射治疗效果。方法2000年4月至2004年11月间对23例70岁以上非小细胞肺癌患者实施了三维适形放射治疗。患者年龄70～87岁,中位年龄82岁。全组的肺功能评价均为中、重度阻塞性通气功能障碍。参照18FDG-PET影像勾画靶取区,处方剂量为40～60 Gy,应用DVH进行靶体积和关键器官和结构的剂量评价。严格控制心脏和肺所接受的平均剂量,全组患者的治疗计划DVH评价显示,患侧肺的V20范围为20%～45%。结果全组存活时间为6～31个月,中位存活时间为10个月。1年存活率为69%。已经死亡的8例中,有6例(75%)死于肺部感染、呼吸衰竭。结论本组有90%以上的患者获得了临床症状的缓解和生活质量的改善,提示对此组患者采用三维适形放射治疗进行准确的局部照射可以获得较好的姑息治疗效果。对于高龄肿瘤患者这一组特殊的病例,借助于PET生物影像学信息实施安全、精确、合理的放射治疗方案,可以将治疗益处最大化,将治疗危险最小化,获得较为满意的临床效果。

乳头状胶质神经元肿瘤的临床诊治

目的:报告1例间变性乳头状胶质神经元肿瘤同时复习文献,归纳总结其诊断要点和治疗策略。方法:12岁患儿间断性头痛1个月就诊,MRI示左侧顶部及丘脑囊实性混杂信号肿块影,予以手术切除。术后病理证实Ki-67 Li约10%,属间变性乳头状胶质神经元肿瘤(WHOⅡ-Ⅲ)。结果:术后患者恢复满意,给予三维适形放射治疗(3D-CRT)57.6Gy/32f。放疗后1个月复查头颅MRI示左颞顶枕部颅骨及头皮软组织呈术后改变,局部未见明显异常对比增强病灶。结论:乳头状胶质神经元肿瘤大多表现良性,肿瘤全切后无复发、转移;增殖指数可能是判断PGNT预后的关键指标,Ki-67较高者术后应行辅助治疗。

食管癌三维适形放射治疗87例临床观察

目的探讨三维适形(3DCRT)放疗治疗食管癌的临床价值。方法对87例食管癌患者,采用深圳一体医疗立体放射定位系统及真空负压袋固定患者,日本东芝16层螺旋CT增强扫描采集患者影像图像,深圳一体医疗立体放射治疗计划系统,一般设5野照射,95%剂量线包括GTV,脊髓在50%剂量线以外,PTV处方剂量,DT50Gy/20F,5f/W。重复CT定位缩野后视患者身体状况和放射反应情况补量DT15—25Gy/5—10F,5F/W。验证:在CT扫描时标出病变上下界结合体中线和椎体前缘为验证参考线,0°和90°(或270°)照射野时观察射野与X、Y、Z轴的关系并拍验证片。应用新华XHA600C型加速器治疗。结果 87例患者随访3年以上,1、2、3年生存率分别92%、72%、63%;食管放射反应Ⅰ级87例(100%),Ⅱ级58例(67%),Ⅲ级16例(18%),Ⅳ级未发生;放射性肺炎和放射性脊髓损伤均未发生。结论该方法使用真空垫固定病人稳定可靠治疗重复性好,CT扫描图像勾画靶区病变精确,计划系统治疗剂量准确分布均匀达到三精的目的。在不加重放射性食管反应和全身反应的同时,安全可靠的保护心脏、肺和脊髓的同时可适当提高单次剂量缩短疗程。三维适形放射治疗食管癌是有效的主要治疗方法.

胸上段食管癌动态IMRT与3DCRT计划的剂量学对比研究

目的比较胸上段食管癌不同放疗计划的剂量学差异。方法对86例上段食管癌患者分别设计调强放疗(IMRT)和三维适形放疗(3DCRT)计划,利用剂量体积直方图来比较两种计划中靶区、危及器官的剂量学差异。结果与3DCRT相比,IMRT靶区覆盖率V95%更高,Dmean也更接近处方剂量,差异有统计学意义(P<0.05);IMRT的靶区适合度指数、靶区剂量不均匀性指数均更接近1;IMRT脊髓D01明显降低,双肺受量略高。结论 IMRT用于治疗胸上段食管癌优于3DCRT。

脑胶质瘤术后三维适形放射治疗疗效32例初步分析

背景与目的:三维适形放射治疗(3DCRT)有别于传统二维放射治疗,它能够对靶区施以精确照射, 并且能减少靶区周围重要器官和正常组织受照射的体积和剂量。本研究拟对脑胶质瘤患者术后采用3DCRT 治疗的疗效及放射毒性反应进行初步分析。方法:接受术后3DCRT治疗的脑胶质瘤患者共32例,其中低分级 (LGG)和高分级(HGG)胶质瘤各为14和18例。中位放射剂量60Gy(50-81Gy),设3-4个野作非共面等中心照射。结果:中位随访时间为15.2个月(4.4-34.6个月),全组肿瘤复发9例(LGG1例,HGG8例),死亡8例 (LGG1例,HGG7例)。1、2年总生存率(OS)分别为89.4%和63.2%,1、2年无进展生存率(PFS)分别为78.5% 和59.4%。LGG和HGG的2年OS分别为92.3%和32.1%(P=0.0156),2年PFS分别为92.3%和0(P=0.0027)。 3级以上急、慢性放射反应的发生率分别为9.4%(3/32)和12.5%(4/32)。结论:3DCRT治疗脑胶质瘤术后患者的毒性是可接受的,对低分级胶质瘤具有良好的疗效,但对高分级胶质瘤的疗效尚不满意,有待进一步研究。

三维适形放疗在食管癌纵隔转移淋巴结治疗中的应用

目的探讨三维适形放疗在食管癌纵隔转移淋巴结治疗中的疗效及临床分析。方法选择2010年3月～2012年3月本院诊治的32例食管癌治疗后纵隔淋巴结转移患者,给予三维适形放疗治疗,对其临床资料进行回顾性分析。结果 32例食管癌治疗后纵隔淋巴结转移患者,经过三维适形放疗治疗后,4例得到完全缓解、19例部分缓解、9例稳定,总有效率为71.88%。放疗期间,13例患者出现放射性肺炎、12例出现放射性食管症状,但是症状不严重,并不影响正常治疗。结论对于食管癌治疗后纵隔淋巴结转移患者,三维适形放射性治疗疗效显著,毒副作用相对较小,值得临床推广。

鼻咽癌后程三维适形放疗疗效分析

目的评价后程三维适形放疗(3DCRT)治疗鼻咽癌(NPC)的近期和远期疗效。方法收集179例NPC患者,其中Ⅰ、Ⅱ、Ⅲ、Ⅳa期分别为16、49、61、53例。所有患者鼻咽和上颈部靶区均采用前程常规放疗联合后程3DCRT,放疗处方剂量为70 Gy/35次,每天1次,每周5次,其中常规放疗36 Gy/18次,3DCRT 34 Gy/17次。结果 179例患者随访率为98.3%(176/179)。全组患者5年局部控制率、无远处转移生存率、无瘤生存率和总生存率分别为75.0%(132/176)、57.4%(101/176)、47.7%(84/176)和62.5%(110/176)。不良反应以Ⅰ、Ⅱ级为主,其发生率与Ⅲ、Ⅳ级不良反应发生率比较,差异均有统计学意义(P<0.01)。结论前程常规放疗联合同期后程3DCRT用于NPC治疗获得了较好的远期疗效和生存质量。

三维适形放疗联合培美曲塞治疗局部晚期肺腺癌的疗效观察

目的探讨三维适形放疗联合培美曲塞治疗局部晚期肺腺癌的临床疗效。方法选取我院2010年9月～2013年1月68例局部晚期肺腺癌患者的资料,根据其治疗方式分为观察组与对照组,各34例,两组患者均采用三维适行放疗,观察组患者同期加用培美曲塞辅助化疗,21d为1个周期,进行2～3个周期,对两组患者的治疗效果及不良反应进行评价。结果观察组患者总有效率高;与对照组患者比较差异有统计学意义(P<0.05)。两组患者治疗不良反应比较差异无统计学意义(P>0.05)。结论三维适形放疗联合培美曲塞治疗局部晚期肺腺癌,能在不增加毒副作用的情况下,提高治疗有效率,改善患者生活质量。

Dosimetric evaluation of CR, 3DCRT and two types of IMRT for breast cancer after conservative surgery

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.

Comparative study of IORT and 3D-CRT for hepato-cellular carcinoma

Objective: To investigate the feasibility of intra-operative radiation therapy (IORT) in hepato-cellular carcinoma (HCC). Methods: Based on the dosage distribution of tumor and adjacent sensitive organs, and dose-volume histogram (DVH), Topslane three-dimensional therapy plan was used to compare IORT and three-dimensional conformal radiation therapy (3D-CRT) in 12 cases of HCC. Results: Taking the center of tumors as the isodose center, the V90 (volume of 90% dose distribution) of IORT was significantly better than that of 3D-CRT, and median absorbed doses of normal organs in IORT was significantly lower than that in 3D-CRT. Conclusion: The V90 of IORT is better than that of 3D-CRT in HCC, and neighboring sensitive organs were effectively protected by IORT. The tumors absorbed dose and local control rate are improved in IORT.