Clinical observation in three-dimensional conformal radiotherapy (3D-CRT) with concurrent chemotherapy in treatment of postoperative cerebral gliomas

Objective:The aim of the study was to investigate the efficacy of three-dimensional conformal radiotherapy (3D-CRT) combined with Temozolomide (TMZ) concurrent chemotherapy in treatment of postoperative cerebral gliomas by prospective randomized controlled trials. Methods: Sixty-two patients with cerebral glioma who had residual tumor were divided into 3D-CRT group (radiotherapy group, n=31) and 3D-CRT with concurrent chemotherapy group (chemoradiotherapy group, n=31) prospectively. All patients received a dose of 50-60 Gy/25-30 F/5-6 weeks by 6 MV-X ray, three-dimensional conformal radiotherapy, 1 f/d, 5 times a week. Chemotherapy regimen was Temozolomide:75 mg/m2/d, concomitantly with radiotherapy, followed by 150-200 mg/m2/d, 5 days, 28 days per cycle, totally 3-6 cycles. Results: The total response rate was 35.3% (11/31) in radiotherapy group. The response rate was 61.3% (19/31) in chemoradiotherapy group. There was significant difference in curative effect (P=0.042). There was no significant difference in survival comparison of two groups (P=0.263). Stratified analysis showed the patients with grade Ⅲ gliomas of chemoradiotherapy group had better prognosis than ones of radiotherapy group (P=0.043). Conclusion: The 3D-CRT with concurrent chemotherapy can improve the survival of cerebral gliomas with pathological grade Ⅲ.

Clinical observation of three-dimensional conformal radiotherapy(3D-CRT) with concurrent chemotherapy in treatment of recurrent cervical cancers

Objective： The aim of the study was to explore the efficacy of three-dimensional conformal radiotherapy （3D- CRT） combined with TP concurrent chemotherapy in treatment of recurrent cervical cancers. Methods： From May 2005 to May 2009, 36 patients with recurrent cervical cancer were treated by 3D-CRT of 60-66 Gy and TP （docetaxel 70 mg/m^2, d1; cisplatin 20 mg/m^2, dl-d3; 21 days per cycle, totally 2 cycles） concurrent chemotherapy. Results： All of the patients had finished the 3D-CRT, the total response rate, complete response rate and partial response rate were 80.0% （28/35）, 45.7% （16/35）, and 34.3% （12/35）, respectively. The pain-alleviation rate was 91.4% （32/35）. The hemorrhage control rate was 94.3% （33/35）. The median overall survival was 21.2 months. The 1-, 2- and 3-year survival rates were 54.3%, 37.1% and 22.8%, respectively. The life qualities of the patients were improved, without any treatment related death. Conclusion： Radiotherapy is effective and well-tolerated for recurrent cervical cancers, and it can promote regional control of the disease and prolong survival time.

The follow-up of 34 children with medulloblastoma who received 3-dimensional conformal radiation therapy

Objective:In our investigation,we studied the patients with medulloblastoma who received 3-dimensional conformal radiation therapy(3DCRT) and recorded their effects,side effects and failure reasons.Methods:From August 2001 to August 2007,34 children with medulloblastoma were treated in our hospital.The age at diagnosis was 3-16 years old,and the mean age at diagnosis was 9.5 years old.Among all the patients,16 cases were included in the high risk group and 18 cases were included in the low risk group.All the patients were performed total resection or subtotal resection and no patients received radiotherapy or chemotherapy before operation.All patients received 3DCRT within 3 weeks after resection.The dose of 30 Gy were given to the whole brain and whole spine,followed by 20-25 Gy boosted to the posterior brain fossa.The median fraction dose was 180 cGy.Every patient received the chemotherapy scheme of the Lomustine,Cisplatinum and Vincristine.Nobody received intrathecal chemotherapy.The tests of the complete blood count,blood biochemistry,hepatic and renal functions were required before every cycle of chemotherapy.Results:5-year overall survival(OS) and 5-year disease free survival(DFS) were 71% and 62% respectively.The median follow-up time was 36.5 months.The 5-year OS of the high risk group was 71% compared to 62% of the low risk group.There were significant difference between the two groups(P = 0.01).There were 13 failure cases in all the patients.Of these 13 patients,10 were dead and the other 3 were alive with tumor.The complete remission(CR) rate was 70.5% and the partial remission(PR) rate was 14%.Among the failure patients,there were 3 patients(8.8%) with the recurrences located in the brain of cribriform region.The 5-year OS of the patients with preoperative metastases was 12.5%(1/8),and which of the patients with residual tumor volume > 1.5 cm3 was 0%(0/5).Through the statistic analysis,it was found that both whether or not the metastases were found before surgery and residual tumor volume have the significant impacts on the prognosis of the children with medulloblastoma(P < 0.05).The major adverse reactions were hematological toxicity(7/34,20.6%) and gastrointestinal reaction(4/34,11.8%).Conclusion:Through the using of 3DCRT for the children with medulloblastoma,the severe side effects rate was not high.The prognosis of the patients in low risk group was satisfied which was opposite to that of the patients in high risk group.And the patients with residual tumor volume > 1.5 cm3 and preoperative metastases also had poor prognosis.It is needed to pay attention to the possible low dose of the brain of cribriform region.

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.

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.

A dosimetric comparative study between conformal and intensity modulated radiation therapy in the treatment of primary nasopharyngeal carcinomas: the Egyptian experience

Objective: The study is a comparative study, the aim of which is to compare 3D conformal radiation therapy (3D-CRT) and intensity modulated radiation therapy (IMRT) in treating nasopharyngeal carcinomas; dosimetrically evaluating and comparing both techniques as regard target coverage and doses to organs at risk (OAR). Methods: Twenty patients with nasopharyngeal carcinoma were treated by 3D-CRT technique and another 20 patients were treated by IMRT. A dosimetric comparison was done by performing two plans for the same patient using Eclipse planning system (version 8.6). Results: IMRT had a better tumor coverage and conformity index compared to 3D-CRT plans (P value of 0.001 and 0.004), respectively. As for the dose homogeneity it was also better in the IMRT plans and the reason for this was attributed to the dose inhomogeneity at the photon/electron junction in the 3D-CRT plans (P value 0.032). Also, doses received by the risk structures, particularly parotids, was significantly less in the IMRT plans than those of 3D-CRT (P value 0.001). Conclusion: IMRT technique was clearly able to increase the dose delivery to the target volume, improve conformity and homogeneity index and spare the parotid glands in comparison to 3D-CRT technique.

Role of radiation therapy in gastric adenocarcinoma

Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.

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).

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.

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.

3D-CRT与静态IMRT在局部晚期非小细胞肺癌治疗中的效果及安全性分析

目的:探讨三维适形放疗(3-dimensional conformal radiation therapy,3D-CRT)与静态调强放疗(intensity modulated radiation therapy,IMRT)在局部晚期非小细胞肺癌(locally advanced non-small cell lung cancer,LANSCLC)治疗中的效果及安全性。方法:选取2017年1月-2019年6月就诊于本院的82例LANSCLC患者,按随机数字表法将其分为A、B组,各41例。A组行静态IMRT,B组行3D-CRT。比较两组治疗效果、计划靶区剂量及治疗安全性。结果:两组治疗总有效率与平均剂量比较,差异均无统计学意义(P>0.05)。A组不均匀性指数(HI)高于B组,而适形指数(CI)水平低于对照组(P<0.05)。A组>Ⅲ度放射性食管炎、血小板减少、>Ⅲ度白细胞减少、>Ⅲ度放射性肺炎及>Ⅲ度消化道反应发生率均低于B组(P<0.05)。结论:3D-CRT与静态IMRT在LANSCLC治疗中的效果相似,但静态IMRT靶区剂量分布更优,能减少放疗毒副反应发生,而其低剂量区照射体积增大,需加以注意。

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.

3DCRT技术治疗原发性肝癌的临床剂量学研究

目的探讨3DCRT技术治疗原发性肝癌的方法、处方剂量与疗效的关系。方法27例有随访结果的肝癌患者,对其肿瘤体积大小、位置、处方剂量及生存期作回顾性总结。结果治疗后肿瘤局部控制率为85.2%(23/27),1年生存率为70.4%(19/27),2年生存率为55.6%(15/27),3年生存率为33.3%(9/27)。所有病人无放射性肝炎等严重副反应发生。结论3DCRT技术治疗不宜手术的肝癌是一种无创而有效的治疗方法,可提高肝癌的局部控制率,不良反应轻微,病人生存质量得到提高。

3DCRT治疗中不同部位恶性肿瘤外周血免疫细胞的动态变化

目的 探讨 3D立体定向适形放射治疗 (3D CRT)前后不同部位恶性肿瘤患者T ,B淋巴细胞和NK细胞的变化。方法 应用流式细胞技术对 4 3例恶性肿瘤患者在 3D CRT前和后 1,4周外周血CD3 ,CD4,CD8细胞 ,CD4/CD8比值 ,CD19细胞和NK细胞的变化。结果 (1)不同部位恶性肿瘤患者 3D CRT前CD3 ,CD4细胞 ,CD4/CD8比值 ,CD19及NK细胞均显著低于健康组 (P <0 .0 5 ,P <0 .0 1) ;(2 )照射后食管癌和直肠癌CD3 ,CD4细胞及CD4/CD8比值下降不明显 ,第4周时已回升 (P >0 .0 5 ) ;脑胶质瘤照射前后变化不显著 (P >0 .0 5 )。 (3)各类肿瘤照射期间CD19细胞、NK细胞无明显下降 (P >0 .0 5 )。结论 恶性肿瘤患者因 3D CRT治疗部位不同 ,其免疫功能细胞的改变有差异 ,临床可据此调整照射剂量、剂量分割及药物对抗。此外 ,CD19细胞和NK细胞对放疗的不敏感性是 3D

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.

颈静脉球瘤的三维立体适形放疗3例报告

目的:探讨三维立体适形放疗治疗颈静脉球瘤的临床疗效。方法:回顾性分析3例颈静脉球瘤的临床资料,3例均采用三维立体适形放疗,肿瘤体积约2-8cm3,肿瘤DT达45-55Gy/9-11f/3-3.5w,随访1-8年。结果:1例头痛、头晕、耳鸣、耳聋等症状完全缓解,复查颅脑增强MRI显示病灶明显缩小;1例耳鸣、头痛、头晕、手足震颤、出汗均消失,继发性高血压自愈,复查颅脑增强MRI显示病灶缩小;1例耳鸣减轻,颅脑CT显示肿瘤稳定。随访后病情均稳定,无复发或转移。结论:三维立体适形放疗能较好的控制肿瘤生长,无明显不良反应,可作为不适合手术、拒绝手术的颈静脉球瘤病人首选的治疗方法,同时也是术后肿瘤残留或复发的重要治疗手段。

3种放疗治疗食管癌近期疗效分析

目的探讨常规(CF)、三维适形(3DCRT)和调强(IMRT)放疗治疗食管癌的近期疗效及放疗反应。方法选择2006年9月～2008年1月我院收治的食管癌患者中行单纯放疗的患者共149例,其中采用常规放疗68例(CF组),三维适形放疗45例(3DCRT组),调强放疗36例(IMRT组),均采用6MVX线照射,2.0Gy/次,5次/周,总剂量为60～66Gy、分30～33次、40～45d完成,比较3组的近期疗效及放疗反应。结果 CF组、3DCRT组和IMRT组有效率分别为70.6%、91.1%和91.7%。CF组与3DCRT组和IMRT组有效率差异有统计学意义(P<0.05～0.01)。各临床分期近期疗效差异有统计学意义(P<0.01)。3组1年局部控制率分别为55.4%、70.5%和69.4%;3组2年局部控制率分别为30.8%、50.0%和58.3%;3组1年生存率分别为75.4%、84.1%和83.3%;3组2年生存率分别为33.8%、54.6%和58.3%。3DCRT组+IMRT组放射性食管炎发生率较CF组高(P<0.05),放射性肺炎发生率CF组较IMRT组+3DCRT组高(P<0.05),骨髓抑制反应3DCRT组+IMRT组较CF组轻(P<0.05)。结论 3DCRT和IMRT方法能提高食管癌的临床疗效,放射反应均可耐受。

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.

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.

Late course shrinking gross tumor volume (GTV) and boost radiotherapy for a special left lung cancer patient whose right lung was resected: a case report

We reported a special case of a locally advanced squamous cell carcinoma of the left lung. Due to pulmonary tuberculosis, the patient had underwent a complete right-side pulmonary lobectomy 20 years ago. Left lung supports his life, he is unable to carry on an operation treatment, so he accepted radiotherapy. Firstly, we defined gross tumor volume (GTV1) by CT simulation location, three-dimensional conformal radiotherapy (3D-CRT) was used until tumor dose reached 50 Gy/25 f. Secondly, by repeating the planning CT scan, defined GTV2, continued to radiotherapy by 2.5 Gy/f until the dose was 65 Gy/31 f. Using the same method for third CT scan, defined GTV3, continued to radiotherapy by 3 Gy/f until the total dose was 74 Gy/34 f. After radiotherapy, the patient acquired complete response and he had no obvious side-effect of radiotherapy. There has been no recurrence for 5 years now.