Chinese Journal of Radiation Oncology

中华放射肿瘤学杂志

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Chinese Journal of Radiation Oncology

	2017 Vol.26 Issue.2 Published 2017-02-15

	Head and Neck Tumors Thoracic Tumors Physics·Biology·Technique Special Feature Review Articles Symposium

Special Feature

	119	The practice and thinking on the standardized training of radiation oncologic residents
		Zhang Ye,Li Yexiong,Wang Lyuhua,Gao Li,Jin Jing,Zhou Zongmei,Wang Shulian,Zhou Caihong,Tang Yu,Deng Lei,Yi Junlin
		Radiation oncology is quite different from other medical majors. Without any related courses in undergraduate education, radiation oncology covers many diseases and is difficult for students to learn. Since 2014, radiation oncology has been enrolled into standardized training subjects for resident physicians in China. Therefore, it is quite important to figure out how to perform the standardized training for radiation oncology physicians. Based on the characteristics of radiation oncology, we innovatively introduce mentors, in addition to tutors, to share responsibility for physician training. Resident physicians receive a comprehensive, systematic, and standardized training in terms of clinical practice, clinical thinking, scientific research, and teaching. Meanwhile, a standardized evaluation system is used to assure the effectiveness of the training for resident physicians. This paper preliminarily investigates the problems and corresponding strategies in the standardized training for radiation oncology resident physicians.
		2017 Vol. 26 (2): 119-122 [Abstract] ( 2293 ) [HTML 1KB] [ PDF 935KB] ( 0 )

Head and Neck Tumors

	123	A clinical study of induction chemotherapy±concurrent chemoradiotherapy for stage N_2-3M₀ nasopharyngeal carcinoma with plasma Epstein-Barr virus DNA>4000 copies/ml
		Chen Junni,Wu Gang,Yang Shipiing,Zhang Shuai,Lin Jie,Wang Fen,Lin Shaoming
		Objective To investigate the value of induction chemotherapy in the treatment of stage N_2-3M₀ nasopharyngeal carcinoma with plasma Epstein-Barr virus (EBV) DNA>4000 copies/ml. Methods A retrospective study was performed on clinical data from 210 patients with stage N_2-3M₀ nasopharyngeal carcinoma and plasma EBV DNA>4000 copies/ml who were admitted to our hospital from 2009 to 2013. In the 210 patients, 101 received induction chemotherapy plus concurrent chemoradiotherapy (NCRT) and 109 concurrent chemoradiotherapy alone (CCRT). The survival rates were calculated by the Kaplan-Meier method. The log-rank test was used for the analysis of survival rates and univariate analysis of the impacts of the changes in the plasma EBV DNA level after induction chemotherapy on the prognosis. Results The 3-year sample size was 154.The NCRT group had significantly higher 3-year disease-free survival (DFS) and distant metastasis-free survival (DMFS) rates than the CCRT group (80.1% vs. 70.6%, P=0.029;87.1% vs. 76.0%, P=0.036), while there was no significant difference in 3-year overall survival (OS) rate between the two groups (88.0% vs. 80.4%, P=0.210). Patients with stage N₂ disease in the NCRT group had significantly higher 3-year DFS and DMFS rates than those in the CCRT group (P=0.031,0.014). Patients with stage N₃ disease in the NCRT group had significantly higher 3-year OS, DFS, and DMFS rates than those in the CCRT group (P=0.029,0.012,0.019). In all the patients, the 3-year OS and DMFS rates were improved with the increase in the cycle number of induction chemotherapy (P=0.020,0.021). In the NCRT group, patients treated with 2, 3, and 4 cycles of induction chemotherapy before radiotherapy had plasma EBV-DNA clearance rates of 51.85%, 76.92%, and 88.57%, respectively (P=0.004). Using the complete clearance of plasma EBV-DNA as a predictor of progression, the sensitivity for the above three groups was 62.50%,66.67% and 75.00(P=0.910), respectively, and the specificity was 57.89%,90.00% and 96.77%(P=0.000), respectively. Conclusions In the treatment of nasopharyngeal carcinoma with plasma EBV DNA>4000 copies/ml, induction chemotherapy improves DFS and DMFS in patients with stage N_2-3M₀ disease and OS in patients with stage N₃ disease;induction chemotherapy dose not improve recurrence-free survival rate. The prognosis and plasma EBV DNA clearance rate are improved with the increase in the cycle number of induction chemotherapy. Using the complete clearance of plasma EBV DNA as a predictor of progression, the sensitivity and specificity in patients treated with 4 cycles of chemotherapy are superior over those in patients treated with 2 or 3 cycles of chemotherapy.
		2017 Vol. 26 (2): 123-127 [Abstract] ( 1308 ) [HTML 1KB] [ PDF 843KB] ( 0 )

	128	A dose volume analysis of brain stem injury after intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma
		Yao Chengyun,Wang Lijun,Kong Cheng,Zhang Lanfang,He Xia,Huang Shengfu,Zhang Yiqin
		Objective To investigate the relationship between the incidence of radiation-induced brain stem injury after intensity-modulated radiotherapy (IMRT) and the radiation dose volume in patients with nasopharyngeal carcinoma. Methods A retrospective analysis was performed on the data of 258 patients newly diagnosed with nasopharyngeal carcinoma who received IMRT in our group from 2005 to 2013. The radiation dose per unit volume of brain stem was analyzed. The relationship between the incidence of brain stem injury induced by IMRT and the radiation dose volume was studied. The survival rate was calculated using the Kaplan-Meier method. The factors influencing the radiation-induced brain stem injury were analyzed using the Cox regression model. Results Two patients with stage T₃ disease and three patients with T₄ disease had radiation-induced brain stem injury. The 3-and 5-year injury incidence rates were 1.6% and 2.4%, respectively. The latency ranged between 9 and 58 months, with a median latency of 19 months. The median D_1% and D_max for the brain stem were 54.24 and 59.22 Gy in all patients, 54.31 and 59.45 Gy in patients with stage T₃ disease, and 61.29 and 66.37 Gy in patients with stage T₄ disease, respectively. In the five patients with brain stem injury, the D_1% and D_max were larger than 60 and 63 Gy, respectively. The univariate analysis showed that the incidence of radiation-induced brain stem injury was correlated with D_1%, D_max, D_{0.1 cm³}, D_{0.5 cm³}, and D_{1.0 cm³}(all P=0.01). The incidence of radiation-induced brain stem injury was significantly lower in patients with D_1%, D_max, D_{0.1 cm³}, D_{0.5 cm³}, and D_{1.0 cm³} no larger than 60, 63, 60, 58, and 56 Gy, respectively (all P=0.00). Conclusions The incidence of radiation-induced brain stem injury after IMRT is relatively low in patients with nasopharyngeal carcinoma. Strict control of the dose to the brain stem may help to reduce the incidence of brain stem injury and improve the long-term quality of life.
		2017 Vol. 26 (2): 128-132 [Abstract] ( 1768 ) [HTML 1KB] [ PDF 795KB] ( 0 )

	133	A clinical analysis of radiotherapy combined with temozolomide for postoperative high-grade glioma
		Li Kaixin,Kong Yue,Dong Baiqiang,Zhamg Xiaoqian,Hua Yonghong,Shi Lei,Yang Ling,Chen Yuanyuan,Hu Qiaoying,Chen Ming
		Objective To assess the efficacy and safety of three-dimensional radiotherapy (3DRT) combined with temozolomide (TMZ) for postoperative high-grade glioma (HGG), and to explore the prognostic factors for HGG patients. Methods A retrospective analysis was performed on the clinical data of 111 patients with postoperative HGG who were admitted to our hospital and received 3DRT combined with TMZ from 2008 to 2015. The efficacy and safety of the treatment were evaluated. The survival rate was calculated by the Kaplan-Meier method and analyzed by the log-rank test. A multivariate prognostic analysis was performed using the Cox model. Results The 1-, 2-, and 3-year sample sizes, overall survival (OS) rates, and progression-free survival (PFS) rates were//, 83.5%/46.9%/35.6%, and 52.2%/34.7%/26.4%, respectively. The common adverse reactions during chemoradiotherapy were acute neurotoxicity, hematologic toxicity, hepatotoxicity, and gastrointestinal toxicity, most of which were tolerable. Pathological grade was an independent prognostic factor for OS and PFS rates (P=,). Conclusions 3DRT combined with TMZ achieves satisfactory efficacy and safety in the treatment of patients with postoperative HGG. Pathological grade is an independent prognostic factor for patients with postoperative HGG.
		2017 Vol. 26 (2): 133-137 [Abstract] ( 1657 ) [HTML 1KB] [ PDF 786KB] ( 0 )

Thoracic Tumors

	138	Incidence and the high-risk factors of intracranial metastases in the perhippocampus regoin in 345 patients with lung cancer
		Chen Dongmei,Meng Xiangying,Shen Ge,Sun Bing,Cong Yang,Liu Chao,Wang Qian,Wang Junliang,Hao Ruimin,Wu Shikai
		Objective To investigate the incidence of and high-risk factors for hippocampal metastasis (HM) in patients with brain metastases of lung cancer, to determine the safety of hippocampus-sparing whole brain radiotherapy (HS-WBRT), and to find out patients eligible for HS-WBRT. Methods A retrospective study was performed on clinical data from 345 patients with brain metastases of lung cancer who were admitted to our hospital from 2011 to 2014. The hippocampus plus a 5-mm margin was delineated. Univariate and multivariate logistic analyses were used to identify high-risk factors for hippocampal metastasis. The Cox model was used for multivariate prognostic analysis. Results In the 345 patients, there were 1621 intracranial metastatic lesions. Sixteen (4.6%) of the 345 patients and 16(0.99%) of the 1621 intracranial metastatic lesions had hippocampal metastasis;42(12.2%) of the 345 patients and 45(2.78%) of the 1621 intracranial metastatic lesions had metastasis in the hippocampus plus a 5-mm margin. The univariate and multivariate logistic analyses showed that the number of brain metastases was correlated with hippocampal metastasis (HR=1.14,P=0.000). In the 139 patients with intracranial progression after treatment, 17(12.2%) had hippocampal metastasis recurrence. The Cox prognostic analysis showed that tumor stage and genetic information were related to the overall survival in patients with brain metastases. Conclusions The number of brain metastases is a high-risk factor for hippocampal metastasis. The lung cancer patients with more brain metastases have a higher incidence of hippocampal metastasis. HS-WBRT is recommended for lung cancer patients with fewer brain metastases, early-stage disease, and genetic mutations or rearrangement.
		2017 Vol. 26 (2): 138-143 [Abstract] ( 1876 ) [HTML 1KB] [ PDF 816KB] ( 0 )

	144	Association between epidermal growth factor receptor mutation subtypes and the prognosis of brain metastases in patients with lung adenocarcinoma
		Zhou Wei,Zhang Jie,Jia Haixia,Cao Jianzhong,Zhang Xiaqin,Song Xin,Li Hongwei
		Objective To explore the association between epidermal growth factor receptor (EGFR) mutation subtypes and the prognosis of brain metastasis in patients with lung adenocarcinoma. Methods A retrospective analysis was performed on the clinical data of 256 patients who were admitted to our hospital and confirmed with brain metastases of lung adenocarcinoma by EGFR mutation detection from 2010 to 2015. The prognostic factors for brain metastases were analyzed. The survival rate was calculated by the Kaplan-Meier method and analyzed by the log-rank test. The univariate and multivariate prognostic analyses were performed by the log-rank test and the Cox proportional hazards model. Results The median survival time was 10.13 months in all patients. The univariate analysis showed that sex,EGFR mutation status,exon 19 deletion,the Karnofsky Performance Status (KPS) score of brain metastases,and targeted therapy were prognostic predictors (P=0.006,0.001,0.010,0.000,0.003). The multivariate analysis showed that the KPS score and exon 19 deletion were prognostic factors for brain metastases (P=0.000,0.045). When grouped into the recursive partitioning analysis classes,all the patients were split into three subgroups with significantly different prognosis (P=0.000). Conclusions Exon 19 deletion is a prognostic predictor of brain metastases in patients with lung adenocarcinoma,which can be integrated into the prognosis scoring system for brain metastases of lung adenocarcinoma. EGFR tyrosine kinase inhibitors improve the survival in patients with brain metastases of lung adenocarcinoma and EGFR mutation,particularly,in those with exon 19 deletion.
		2017 Vol. 26 (2): 144-149 [Abstract] ( 1754 ) [HTML 1KB] [ PDF 832KB] ( 0 )

	150	A correlation analysis of the changes in plasma level of transforming growth factor beta1 and lymphocyte subset percentages after radiotherapy for patients with lung cancer
		Luo Jing,Wei Tingting,Xu Kunpeng,Xu Liming,Gong Linlin,Ren Kai,Wang Xin,Zhao Lujun
		Objective To investigate the relationship between the change in plasma level of transforming growth factor-beta1(TGF-β₁) after radiotherapy (RT) and short-term treatment outcomes in patients with lung cancer, and to analyze its relationship with the changes in lymphocyte subset percentages in peripheral blood. Methods In a prospective study, blood samples before, during, and after treatment were collected from 39 patients with lung cancer who were treated in our hospital from 2014 to 2016. Plasma level of TGF-β₁ was measured by enzyme-linked immunosorbent assay. The percentages of lymphocyte subsets in peripheral blood were determined at each time point. At one month after RT, chest computed tomography was performed to evaluate the short-term treatment outcomes. The response evaluation criteria in solid tumors were used to determine whether there was any response or not. Results Patients with lower plasma levels of TGF-β₁ after RT had significantly better short-term treatment outcomes (P<0.05). The changes in plasma level of TGF-β₁ after 2 and 4 weeks of RT and at the end of RT were correlated to the changes in the percentages of CD₄(+) T and CD₈(+) T cells and the CD₄(+)/CD₈(+) ratio at the same time point (r=-0.581,-0.516,-0.648, P<0.001;r=0.558, 0.545, 0.626, P<0.001;r=-0.615,-0.648,-0.598, P<0.001). Conclusions Lung cancer patients with reduced TGF-β₁ levels after RT have better treatment outcomes than those without decreases in TGF-β₁ levels after RT. The mechanism may be related to anti-tumor immunity.
		2017 Vol. 26 (2): 150-154 [Abstract] ( 1754 ) [HTML 1KB] [ PDF 788KB] ( 0 )

	155	Clinical study of non-operative staging of esophageal squamous cell carcinoma underwent intensity-modulated radiotherapy combined with chemotherapy
		Chen Junqiang, Lin Yu, Su Tingfeng,Wang Bingyi,Liu Pingping,Li Jiancheng,Wu Junxin,Pan Jianji,Chen Chuanben
		Objective To compare different non-operative clinical staging criteria regarding their accuracy and feasibility in evaluation of patients with esophageal squamous cell carcinoma (ESCC) receiving concurrent intensity-modulated radiotherapy (IMRT) and chemotherapy. Methods A study was performed on clinical data from 242 ESCC patients who received concurrent IMRT and chemotherapy in our hospital from 2008 to 2014. Prognostic prediction was compared between the Chinese 2009 staging system, the 6^th edition staging system, and a suggested staging system. The survival rates were calculated by the Kaplan-Meier method and analyzed by the log-rank test. A prognostic analysis was made by the Cox model. ResultsThe 3-year sample size and overall survival rate were 168 and 47.4%, respectively. Esophageal tumor volume and the maximum diameter of metastatic lymph nodes were prognostic factors (P=0.000,0.000). An intersection of T₃ and T₄ survival curves was found in the Chinese staging system and the 6^th version staging system (P=0.696,0.594), while an intersection of N₁ and N₂ survival curves was found in the Chinese staging system (P=0.068). The T staging based on esophageal tumor volume, N staging based on the maximum diameter of metastatic lymph nodes, and their combination could achieve a good separation of survival curves of different stages (P=0.000,0.000,0.000). Conclusions The T staging based on esophageal tumor volume combined with the N staging based on the maximum diameter of metastatic lymph nodes is an convenient non-operative clinical staging approach for prognostic prediction of ESCC patients receiving concurrent IMRT and chemotherapy.
		2017 Vol. 26 (2): 155-159 [Abstract] ( 1873 ) [HTML 1KB] [ PDF 879KB] ( 0 )

	160	Role of radiotherapy in patients with stage Ⅰ—Ⅱ diffuse large B-cell lymphoma of waldeyer’s ring in remission after chemotherapy
		Lu Ke,Zhu Yuan,Liu Jianjiang,Liu Peng,Zhang Na,Liu Luying,Luo Jialin,Zhou Ning
		Objective To investigate the impacts of adjuvant radiotherapy on the prognosis of patients with stage Ⅰ—Ⅱ diffuse large B cell lymphoma of Waldeyer’s ring (WR-DLBCL) who achieved complete remission (CR) after chemotherapy. Methods Clinical data were collected from 130 patients with stage Ⅰ—Ⅱ WR-DLBCL who were admitted to our hospital from 2005 and 2013. All the patients achieved CR after at least two cycles of cyclophosphamide,doxorubicin/epirubicin,vincristine,and prednisone (CHOP)-based chemotherapy or rituximab plus CHOP (R-CHOP)-based chemotherapy. In the 130 patients,43 received R-CHOP (including 25 patients undergoing radiotherapy) and 87 CHOP (including 76 patients undergoing radiotherapy);29 received chemotherapy alone and 101 chemoradiotherapy. The survival rates were calculated by the Kaplan-Meier method and analyzed by the log-rank test. Univariate and multivariate prognostic analyses were made by the log-rank test and the Cox model,respectively. Results In all patients,the 5-year sample size was 101. The univariate analysis showed that patients with an Eastern Cooperative Oncology Group (ECOG) score of 0 had significantly higher 5-year overall survival (OS) and disease-free survival (DFS) rates than those with an ECOG score of 1(95.6% vs. 80.1%,P=0.000;95.7% vs. 75.4%,P=0.029). Patients treated with chemotherapy alone had significantly lower 5-year OS and DFS rates than those treated with chemoradiotherapy (77.1% vs. 91.7%,P=0.048;77% vs. 87.4%,P=0.037). The multivariate analysis by the Cox model showed that ECOG score was a prognostic factor for both OS and DFS (P=0.047,0.003). Adjuvant radiotherapy was related to improved DFS rather than OS (P=0.039,0.133). Conclusions Stage Ⅰ—Ⅱ WR-DLBCL patients with low ECOG scores have better prognosis than those with high ECOG scores. Patients with CR after chemotherapy may benefit from adjuvant radiotherapy. The conclusions need to be further confirmed by prospective randomized controlled trials.
		2017 Vol. 26 (2): 160-164 [Abstract] ( 2352 ) [HTML 1KB] [ PDF 814KB] ( 0 )

	165	Feasibility of placing a dose constraint to peritoneal space instead of bowel loop in protection of the small intestine during intensity-modulated radiotherapy for rectal cancer
		Qian Jianjun,Sun Yanze,Yang Yongqiang,Chen Liesong,Tian Ye
		Objective To compare the dose volume and normal tissue complication probability (NTCP) of small intestine between intensity-modulated radiotherapy (IMRT) with dose constraints to the peritoneal space (PS) and the bowel loop (BL) in the treatment of rectal cancer, and to investigate the feasibility of placing a dose constraint to the PS instead of the BL in protection of the small intestine. Methods A total of 24 patients with rectal cancer undergoing postoperative adjuvant radiotherapy were enrolled as subjects. In the 24 patients, 12 were treated in supine position and 12 in prone position. The weekly computed tomography (CT) scans from pre-treatment to weeks 1-4 of treatment were defined as Plan, 1 W, 2 W, 3 W, and 4 W. Contours of PS and BL were delineated on all CT images. Based on the Plan CT images, two IMRT plans, P_PS and P_BL, were designed with dose constraints to the PS and BL, respectively. The method was applied to 1-4 W CT images. For each CT scan, the dose volume and NTCP of the small intestine were evaluated in P_PS and P_BL. Results A total of 109 sets of CT images were acquired from 24 patients, and 218 plans were designed and copied. The median volume of the PS and BL was 1339.28 and 250.27 cm³, respectively. For the Plan CT scans, V₁₅ values of the PS in P_PS plan and the BL in P_BL plan were 918.96 and 199.57 cm³, respectively. For all CT scans, the dose volume of the small intestine in P_PS, in most cases, was lower than that in P_BL, while V₁₅ values in P_PS and P_BL were 170.07 and 178.58 cm³(P=0.000). The dose volume of the small intestine was correlated with V₁₅(P=0.000). P_PS had significantly lower NTCP of chronic and acute adverse reactions than P_BL (2.80% vs. 3.00%, P=0.018;57.32% vs. 58.64%, P=0.000). In patients with prone and supine treatment positions, most of the dose volume and NTCP of the small intestine in P_PS were significantly lower than those in P_BL (P<0.05 for V₁₀, V₁₅, V₃₀, and NTCP of acute adverse reactions). Conclusions It is feasible to place a dose constraint to the PS instead of the BL for protection of the small intestine during IMRT for rectal cancer. V₁₅<830 cm³ can be referred to as the objective function of dose restraint.
		2017 Vol. 26 (2): 165-170 [Abstract] ( 1721 ) [HTML 1KB] [ PDF 1170KB] ( 0 )

	171	Effect of independent breath-holding technology on target geometry in radiotherapy for liver cancer
		Hong Chaoshan,Zhu Xiaodong,Qu Song,Qing Liping,Fu Qingguo,Deng Ye
		Objective To use the fusion image of the end-inhalation holding (EIH) phase and end-exhalation holding (EEH) phase to define the target volume of individual patient with liver cancer, and to evaluate the target geometry, feasibility, and clinical significance of the technology. Methods Eighteen patients with liver cancer who were treated in our hospital from 2012 to 2013 were enrolled as subjects. With the same posture and scan range, all patients underwent contrast-enhanced three-dimensional computed tomography (3DCT) scans in the phases of free breathing (FB), EIH, and EEH. Gross tumor volume (GTV), clinical target volume (CTV), and organ of risk (OAR) were delineated on the above images. CTV_FB was defined as GTV on the FB phase image (GTV_FB) plus a margin of 10 mm, while planning target volume (PTV_FB) was defined as CTV_FB plus a margin of 10 mm in the right-left and anterior-posterior directions and a margin of 20 mm in the superior-inferior direction. GTV_EI and GTV_EE were defined as GTV on the EIH and EEH images, respectively. Based on the EEH images, the registered EEH and EIH images were fused to form GTV_EI+EI. CTV_EI+EE was defined as GTV_EI+EI plus a margin of 10 mm, while PTV_EI+EE was defined as CTV_EI+EE plus a margin of 5 mm in the right-left and anterior-posterior directions and a margin of 10 mm in the superior-inferior direction. The Pinnacle³ v8.0m treatment planning system was used to design two 3D conformal radiotherapy plans for each patient. The volume, degree of inclusion (DI), matching index (MI), and central displacement of CTV_FB and CTV_EI+EE, as well as PTV_FB and PTV_EI+EE, were compared between the two plans. Results In the 18 patients, the mean CTV_FB was significantly smaller than the mean CTV_EI+EE (149.00±87.54 cm³ vs. 188.17±125.72 cm³, P=0.014);there was no significant difference between the mean PTV_FB and PTV_EI+EE (276.68±146.41 cm³ vs. 253.66±117.35 cm³, P=0.080). DI of CTV_FB to CTV_EI+EE, PTV_FB to PTV_EI+EE, CTV_EI+EE to CTV_FB, and PTV_EI+EE to PTV_FB were (99.83±0.09)%,(84.55±8.45)%,(80.83±12.31)%, and (99.78±0.08)%, respectively. MI of CTV_EI+EE to CTV_FB and PTV_EI+EE to PTV_FB were 0.83±0.07 and 0.87±0.03, respectively. The central displacements of CTV_EI+EE from CTV_FB in x, y, and z axes were 0.55±1.07 cm, 0.76±3.02 cm, and -0.26±1.98 cm, respectively (P=0.432, 0.971, 0.587). Conclusions In the treatment of liver cancer, the target volume delineation and image fusion using 3DCT images in EIH and EEH phases may avoid target omission due to respiratory movement, making it possible to increase radiation dose to target volume and improve the efficacy of radiotherapy.
		2017 Vol. 26 (2): 171-177 [Abstract] ( 1887 ) [HTML 1KB] [ PDF 917KB] ( 0 )

Physics·Biology·Technique

	178	Knowledge-based semi-automated optimization of intensity-modulated radiotherapy plans using a volume modulated arc therapy-configured model
		Zhang Yibao,Jiang Fan,Yue Haizhen,Hu Qiaoqiao,Zhang Jian,Gong Jian,Wu Hao
		Objective To evaluate the feasibility and dosimetric features of a volume modulated arc therapy (VMAT)-configured model in knowledge-based optimization of fixed-field dynamic intensity-modulated radiotherapy (IMRT) plans based on the Varian RapidPlan system. Methods ① A dose-volume histogram prediction model was trained with 81 qualified preoperative VMAT plans for rectal cancer and then statistically verified. ② For clinically approved 10 IMRT plans with the same dose prescription, the above model was used to automatically generate new optimization parameters and dynamic multileaf collimator (MLC) sequences with field geometry and beam energy unchanged. ③ In order to rule out the disparities between different versions, a single algorithm was used to calculate the absolute doses of the original and new plans. ④ Statistical analyses were performed on dosimetric parameters after comparable target dose coverage was achieved in the two plans by appropriate normalization. Results On the basis of similar target dose homogeneity and coverage, RapidPlan significantly reduced the doses to the urinary bladder (D_50% by 9.01 Gy, P=0.000;D_mean by 8.08 Gy, P=0.005) and the femoral head (D_50% by 4.20 Gy, P=0.000;D_mean by 3.84 Gy, P=0.005) but significantly elevated the mean total number of monitor units (1211±99 vs. 771±79, P=0.000) and the number of fields with multiple MLC carriage groups. The knowledge-based semi-automated optimization caused a significantly larger number of high-dose hotspots but a similar D_2%(52.54 vs. 52.71 Gy, P=0.239). Conclusions The VMAT model can be used for the knowledge-based semi-automated optimization of IMRT plans to enhance the efficiency and OAR protection. However, the resulting high-dose hotspots need further manual intervention.
		2017 Vol. 26 (2): 178-181 [Abstract] ( 1964 ) [HTML 1KB] [ PDF 792KB] ( 0 )

	182	Effect of leaf movement speed on setup error of multileaf collimator in volumetric modulated arc therapy mode
		Wang Guangshan,Yang Bo,Pang Tingtian,Sun Xiansong,Qiu Jie
		Objective To study the effect of leaf movement speed on the setup error of multileaf collimator (MLC) in RapidArc mode, and to improve quality assurance and verify the reliability of RapidArc. Methods Referring to the PicketFenceStatic_M120.dcm and PicketFenceRA_M120.dcm files, the Tilt tests with different adjacent leaf speed were designed and setup errors of MLC were obtained by analyzing electronic portal imaging device images. Results In the Tilt tests, the setup errors gradually increased from gap11 to gap50 in both static gantry mode and RapidArc mode. With a gantry angle of 270°, gap41 had the maximum setup error of -0.55 mm. In the RapidArc mode, gap46 had the maximum setup error of -0.67 mm. The deviation of gap width was no greater than 15% in any mode. There was no significant difference in deviation pattern of gap width between four modes with different gantry angles. The same gaps in different stripes showed a consistent trend in gap width. The RapidArc mode had a larger variation in percentage deviation of gap width than the static gantry mode. Conclusions The setup error increases with the increase in the speed of MLC leaf. The variation in the leaf speed has no significant impact on the gap width. There is no correlation between the leaf speed and the deviation of gap width. Four different gantry angles give similar deviation patterns of gap width, suggesting that the deviation of gap width is related to the leaf rather than the gantry angle. The RapidArc mode has a greater impact on the gap width than the fixed gantry mode.
		2017 Vol. 26 (2): 182-186 [Abstract] ( 1932 ) [HTML 1KB] [ PDF 1014KB] ( 0 )

	187	Relationship between the overlap volume of organ at risk and target and the dose to organ at risk in intensity-modulated radiotherapy
		Pang Haowen,Sun Xiaoyang,Yang Bo,Shi Xiangxiang,Tang Tao,Wu Jingbo
		Objective To explore the relationship between the overlap volume of organ at risk (OAR) and target (V_overlap) and the mean dose to OAR (D_mOAR) in intensity-modulated radiotherapy (IMRT). Methods Fifty randomly selected patients undergoing IMRT for nasopharyngeal carcinoma (NPC) and an equal number of patients undergoing radical IMRT for cervical cancer in our hospital were enrolled as subjects. The relationship between V_overlap and D_mOAR in IMRT was analyzed. The Matlab software was used to generate function to fit the relationship between V_overlap and D_mOAR for different OARs. Results The V_overlap varied among patients with NPC or cervical cancer. The ratio of V_overlap to the volume of OAR (V_OAR) was positively correlated with the ratio of D_mOAR to the prescribed dose (D_p)(all P=0.01). A function was generated to fit the correlation between V_overlap/V_OAR ratio and D_mOAR/D_p ratio. Conclusions In IMRT, patients have different V_overlap/V_OAR ratios due to varied target volume, disease stages, OAR filling status, and OAR volume. As criteria for plan verification, a specific D_mOAR value for each OAR should be calculated before radiotherapy planning based on the corresponding correlation function and the V_overlap/V_OAR ratio with a fixed dose prescription. It can be used to reduce the subjective influence on the optimization of radiotherapy planning.
		2017 Vol. 26 (2): 187-191 [Abstract] ( 1850 ) [HTML 1KB] [ PDF 912KB] ( 0 )

	192	Observation of CT-MRI image fusion in postoperativeprecise radiotherapy for gliomas
		Huang Rong,Wu Hui,Lu Xiaoxu,Xu Jing,Wang Yanling,Li Dingjie,Cheng Zhiyao
		Objective To investigate the value of computed tomography (CT)-magnetic resonance imaging (MRI) image fusion in target volume delineation of postoperative precise radiotherapy for gliomas. Methods Thirty-six patients newly diagnosed with gliomas were enrolled and received postoperative intensity-modulated radiotherapy. Landmark (L) combined with manual fusion (M) and maximization of mutual information (MI) was used for image fusion. Target volume and organs at risk were delineated based on CT images and fused images, respectively. Comparison of the volume was made by pairwise t test. The distance from a landmark on CT image to the corresponding one on MRI image was calculated. The volume method and geometric center method were used to calculate the degree of volume overlap and changes in central positions after image fusion. Results The L+M+MI method achieved a high registration accuracy in image fusion, with a registration error less than 2 mm. In patients with grade Ⅲ-IV gliomas, the CT images yielded significantly smaller gross tumor volume (GTV) and clinical target volume (CTV) than the MRI images (74.62±46.91 vs. 105.99±58.86 cm³, P=0.042;304.03±130.05 vs. 387.94±150.12 cm³, P=0.040). After image fusion, the smallest change in central position occurred in the chiasma (1.32±1.42 mm), and the largest change occurred in CTV (7.99±11.06 mm), followed by GTV and the brain stem. Conclusions CT-MRI image fusion helps to reduce the uncertainty of target volume delineation in patients with gliomas, especially in those with edema and residual tumor after surgery.
		2017 Vol. 26 (2): 192-196 [Abstract] ( 1831 ) [HTML 1KB] [ PDF 916KB] ( 0 )

	197	Commission of volumetric modulated arc therapy with electronic portal image device
		Ma Yangguang,Pei Yuntong,Mai Rizhen,Hu Jinyan,Liu Shuaipeng,Jia Fei,Wang Tao,Liu Lele,Guo Yuexin
		Objective To apply electronic portal imaging device (EPID) in the quality assurance of volumetric modulated arc therapy (VMAT) delivered by TrueBeam linear accelerator. Methods The Shaper software and Eclipse treatment planning system (TPS) were used to edit the VMAT plan delivered by TrueBeam linear accelerator. The EPID was used to evaluate the setup accuracy of multi-leaf collimator (MLC) and clinical dosimetry. TA:a field with a size of 0.5 cm×20.0 cm was exposed with gantry angles of 0°, 90°, and 270°, respectively;TB:the flatness and stability of the field were tested with different combinations of dose rate and gantry angle speed;TC:the setup accuracy of MLC was evaluated with or without rotation;TD:the accuracy of speed change control of MLC was evaluated with or without rotation;TE:the accuracy of simultaneous changes in dose rate and gantry angle speed was evaluated;TF:Clinical patients were evaluated. The Matlab software was used to analyze the results. Results TA:the full width at half maximum of superimposed fields exposed with gantry angles of 0°, 90°, and 270°was 0.39 mm larger than that of the field exposed with a gantry angle of 0°. TB:the difference in flatness was less than 0.5% between fields with different combinations of dose rate and gantry angle speed. TC:the maximum difference in field center was 0.45 mm between EPID measurement and TPS setting. TD:the maximum difference in MLC position was 0.69 mm between EPID measurement and TPS setting. TE:the maximum difference was 0.42 mm between fields. TF:for all the patients, the lowest γ passing rate was 96.4% according to the criterion of 3%/3 mm. Conclusions EPID is an accurate and convenient approach for VMAT quality assurance, which provides an option for physicists to reduce workload.
		2017 Vol. 26 (2): 197-201 [Abstract] ( 1908 ) [HTML 1KB] [ PDF 954KB] ( 0 )

	202	Dosimetric characterization of a novel dual-energy medical linear accelerator without a flattening filter
		Yang Xin,Sun Wenzhao,Chen Li,Luo Guangwen,Lin Mao-sheng,Huang Xiao-yan
		Objective To study the dosimetric characteristics of flattened and flattening filter free (FFF) beams with 6 MV and 10 MV photon energy using a novel dual-energy medical linear accelerator (Elekta Versa HDTM), to identify the dosimetric characteristics and advantages of FFF beams, and to provide a basis for their clinical application. Methods The percentage depth dose (PDD), profiles/dose rate of off-axis ratio (OAR), field size, penumbral width, dose out of the fields, collimator scatter factor (S_c), and total scatter factor (S_c,p) were compared between flattened and FFF beams. Results (1) After beam energy matching, the FFF beams had the same beam energy with the flattened beams. The matching error of PDD at a depth of 10 cm was less than 1% between fields.(2) The FFF beams had a smaller variation in dose rate of OAR with the depth than the flattened beams.(3) The FFF beams had smaller variations in field size and penumbral width than the flattened beams. Moreover, the penumbral width of the FFF beams increased with the increasing field size or depth. The FFF beams had a lower dose out of the fields than the flattened beams.(4) The FFF beams had smaller variations in S_c and S_c,p with the field size and depth than the flattened beams. Conclusions Removal of the flattening filter can substantially improve the dose rate, shorten radiotherapy time, and reduce leakage and scattering of the head. The dosimetric advantages make the FFF beams appropriate for clinical treatment.
		2017 Vol. 26 (2): 202-209 [Abstract] ( 1847 ) [HTML 1KB] [ PDF 0KB] ( 0 )

	210	Application of new three-dimensional printed tissue compensators in radiotherapy
		Zhang Min,Zhao Bo,Yin Jinpeng,Liu Siwei,Gao Xianshu,Qin Shangbin,Wang Qingguo,Zhao Qing,Liu Ling,Li Xiaomei,Li Hongzhen,Li Xiaoying,Ma Mingwei
		Objective To develop three-dimensional (3D) printed tissue compensators for irregular body surface in radiotherapy. Methods Pre-clinical evaluation was made among human phantoms with no tissue compensators, commercially available tissue equivalent bolus, and 3D printed tissue compensators. Perineal computed tomography (CT) images were acquired from the above three human phantoms with the same prescription dose to the same target volume (D_95%=100 cGy). Intensity-modulated radiotherapy plans for the three human phantoms were designed using the same treatment planning system. The dosimetric parameters of planning target volume (PTV) were compared between the three plans. The dosimetric parameters were evaluated among 10 patients who were treated with 3D printed tissue compensators. Results The electron density of the selected material was 1.00-1.01. The phantoms with no tissue compensators, commercially available tissue equivalent bolus, and 3D printed tissue compensators had D_max of 182.9, 118.9, and 114.8 cGy, D_mean of 146.2, 107.7, and 104.1 cGy, and homogeneity index (HI) of 0.565, 0.15, and 0.11 for PTV, respectively. All the 10 patients had highly personalized 3D printed tissue compensators with satisfactory dose homogeneity (HI=0.03-0.15 with a median of 0.06). Five patients with Paget′s disease of penis and scrotum benefited from the support and fixation by 3D printed tissue compensators. Conclusions The highly personalized 3D printed tissue compensators can provide a positioning support for patients and effectively increase the dose to the skin.
		2017 Vol. 26 (2): 210-214 [Abstract] ( 1587 ) [HTML 1KB] [ PDF 903KB] ( 0 )

	215	Gene expression profiling of a radioresistant esophageal squamous cancer cell line
		Zhou Lingran,Bai Lu,Wang Liang,Cheng Min,Qian Liting
		Objective To establish a radioresistant esophageal squamous cancer cell line, and to identify the radioresistant genes and mechanisms. Methods The radioresistant KYSE410-res cell line was established by repeated exposure of cell line KYSE410 to radiation. The proliferation and apoptosis of esophageal squamous cancer cells were evaluated before and after radiation. The changes in gene expression of the esophageal squamous cancer cells after radiation were determined by gene microarray and analyzed by group t test. The genes with significant difference in expression after radiation were validated. Results The KYSE410-res cells had significantly enhanced proliferation and anti-apoptosis than the KYSE410 cells (all P<0.05). The result of gene microarray showed that compared with the KYSE410 cells, the KYSE410-res cells had the expression of 463 and 251 genes upregulated and downregulated by no less than 4 folds, respectively. Those genes with different expression levels after radiation were mainly responsible for cell proliferation, adhesion, signal transduction, angiogenesis, reactive oxygen metabolism, cell damage repair, and the MAPK/ERK signaling pathway. OAS2 and UBD were key proteins in the network. In the KYSE410-res cells, the expression of HLA-DQB1, MMP1, NCAM₁, ZNF521, GPC6, SELENBP1, LCN15, and TFPI-2 genes measured by real-time PCR was consistent with that measured by gene microarray. Conclusions Abnormal activation of the MAPK/ERK signaling pathway, upregulated expression of OAS2 and UBD, downregulated expression of TFPI-2, and upregulated expression of MMPs may play a role in radioresistance of esophageal cancer cells.
		2017 Vol. 26 (2): 215-221 [Abstract] ( 1820 ) [HTML 1KB] [ PDF 945KB] ( 0 )

	222	Pretreatment with chronic intermittent hypobaric hypoxia attenuates radiation-induced heart damage in rats
		Wu Yajing,Wang Jun,Wang Yuan,Wang Sheng,Liu Qing,Wang Yi,Cao Feng,Cheng Yunjie,Jiao Wenpeng
		Objective To study cardioprotective effects of pretreatment with chronic intermittent hypobaric hypoxia (CIHH) on acute radiation-induced heart damage, and to explore the potential mechanisms. Methods Forty-eight male adult Sprague-Dawley rats were randomly divided into control group, CIHH group, radiation group, and CIHH+radiation group. Pretreatment with CIHH was performed by placing rats in a hypobaric chamber before radiation. Left ventricular function was recorded and myocardial infarction area was determined. Collagen volume fraction (CVF) was calculated after Masson staining. The activity of total superoxide dismutase (T-SOD) and content of lipid peroxide malondialdehyde (MDA) were determined by enzyme linked immunosorbent assay. The expression levels of a marker of fibrosis, collagen type I (COL-1), and two markers of endoplasmic reticulum stress, GRP78 and CHOP, were analyzed by Western blot. Difference test using two factor analysis of variance. Results Compared with the radiation group, the CIHH+radiation group had improved left ventricular systolic and diastolic function and reduced myocardial infarction area;the CIHH+radiation group also had significantly reduced CVF, significantly lower expression of COL-1, significantly higher activity of T-SOD, significantly lower concentration of MDA, and significantly lower expression levels of GRP78 and CHOP (P<0.01,P<0.01;(185.19±3.20) vs. (156.61±4.60) U/mgprot, P<0.01;(1.36±0.17) vs. (2.36±0.21) nmol/mgprot, P<0.01;P<0.05;P<0.01). Conclusions Pretreatment with CIHH can to a certain degree reduce radiation-induced damage to the cardiac coronary artery, enhance cardiac tolerance to ischemia/reperfusion injury, reduce myocardial infarction area after ischemia/reperfusion, and improve collagen deposition in perivascular region and myocardial stroma. CIHH protects myocardium probably via inhibition of oxidative stress, endoplasmic reticulum stress, and myocardial fibrosis.
		2017 Vol. 26 (2): 222-227 [Abstract] ( 1657 ) [HTML 1KB] [ PDF 1230KB] ( 0 )

	228	A study of radiation injury in rat C6 glioma cell line by ¹H-nuclear magnetic resonance spectroscopy
		Li Hongxia,Cui Yi,Xu Yanjie,Li Fuyan,Shi Wenqi,Wang Jianzhen,Zeng Qingshi
		Objective To study the radiation injury of rat C6 glioma cell line by high resolution, ¹H-nuclear magnetic resonance (¹H NMR) spectroscopy, and to preliminarily investigate its mechanism. Methods Metabolite concentrations in C6 cells were determined by ¹H NMR spectroscopy. Comet assay was used to evaluate DNA damage. Flow cytometry was used to determine the cell cycle and apoptosis rate. Colony-forming assay was used to measure the colony-forming rate and preliminarily investigate the mechanism of radiation injury. The results were analyzed by one-way analysis of variance and Pearson correlation analysis. Results With the increase in radiation dose from 0 Gy to 1, 5, 10, and 15 Gy, DNA damage was enhanced in a dose-dependent manner (P=0.000-0.690);the percentage of cells in G₁ phase increased (P=0.026-0.749);the apoptosis rate significantly increased (all P=0.000);the colony-forming rate significantly declined (P=0.000-0.004);the Lac/Cr ratio significantly decreased (P=0.000-0.015), which had a negative linear correlation with DNA damage parameters (tail length, r=-0.971;%DNA in the tail, r=-0.998;tail moment, r=-0.995) and apoptosis rate (r=0.978). Conclusions ¹H NMR spectroscopy reveals that the change in the Lac/Cr ratio is associated with injury and apoptosis of C6 cells after radiation. ¹H NMR spectroscopy has the potential to predict radiation injury of glioma.
		2017 Vol. 26 (2): 228-233 [Abstract] ( 1667 ) [HTML 1KB] [ PDF 1133KB] ( 0 )

Review Articles

	234	Research advances in stereotactic body radiation therapy for primary liver cancer
		Tong Jinlong,Zheng Qin,Sun Xinchen
		Stereotactic body radiation therapy (SBRT) adopts different tumor-killing mechanisms from the conventional fractionated radiotherapy. In SBRT, a single high-dose radiation can destroy the membrane of tumor cells and induce the release of tumor-associated antigen, also named in situ tumor vaccine, which stimulates the immune system to kill the residual tumor;a single-fraction radiation with a dose larger than 8-10 Gy can induce rapid apoptosis of vascular endothelial cells via the acid sphingomyelinase pathway at 1-6 hours after radiation, which causes tumor vascular occlusion and secondary tumor-killing effects. In order to understand whether SBRT improves the clinical treatment outcomes via the above mechanisms, this paper reviews the clinical research advances in SBRT for primary liver cancer.
		2017 Vol. 26 (2): 234-238 [Abstract] ( 1875 ) [HTML 1KB] [ PDF 811KB] ( 0 )

	239	Application of diffusion-weighted magnetic resonance imaging in radiotherapy for esophageal carcinoma
		Li Guanghu,Qian Liting
		As an important component of functional magnetic resonance imaging, diffusion-weighted magnetic resonance imaging (DWI) can provide qualitative and quantitative information for tumor evaluation and distinguish esophageal lesions and mediastinal lymph node metastasis. DWI-computed tomography fusion images facilitate the delineation of target volume. During radiotherapy or concurrent chemoradiotherapy for esophageal carcinoma, monitoring the changes in apparent diffusion coefficient value helps to predict the early treatment outcomes and prognosis;DWI compensates for the shortcomings of radiography alone in the evaluation of short-term treatment outcomes. This paper reviews the application of DWI in the diagnosis, delineation of target volume, assessment of treatment outcomes, and prognostic prediction in radiotherapy for esophageal carcinoma.
		2017 Vol. 26 (2): 239-242 [Abstract] ( 1655 ) [HTML 1KB] [ PDF 782KB] ( 0 )

	243	Early evaluation of tumor radiation response by medical imaging
		Zhang Nasha,Zhu Hui,Zhu Jian,Yu Jinming
		Response evaluation criteria in solid tumors is widely used for assessing tumor response to radiotherapy in clinical practice. However, it is clearly insufficient. Currently there is no ideal method for early evaluation of tumor radiation response. This paper reviews studies on early evaluation of radiotherapy efficacy by positron emission tomography-computed tomography (CT), magnetic resonance imaging, and CT. This paper also further explores the necessity and feasibility of CT values of megavoltage CT scans in early evaluation of the radiosensitivity of tumor during tomotherapy.
		2017 Vol. 26 (2): 243-246 [Abstract] ( 1823 ) [HTML 1KB] [ PDF 774KB] ( 0 )

Symposium

	247	Application of small animal radiation research platform in radiotherapy
		Zhang Yanjun,Deng Yun,Xu Qing,Zhang Zhen
		Small Animal Radiation Research Platform (SARRP) is a highly efficient platform specifically designed for research in the fields of radiation oncology and radiobiology. This platform possesses precise radiometers with gantries capable of isocentric, coplanar, and non-coplanar conformal irradiation. Based on the three-dimensional images acquired by the cone-beam computed tomography, the platform can perform “real time” treatment planning and irradiation, which assures timeliness for precise irradiation and research on small animals. The wide application of SARRP not only accelerates the bench to bedside translation, but also facilitates the development of radiation oncology and radiobiology.
		2017 Vol. 26 (2): 247-249 [Abstract] ( 1526 ) [HTML 1KB] [ PDF 882KB] ( 0 )

	250


		2017 Vol. 26 (2): 250-250 [Abstract] ( 1122 ) [HTML 1KB] [ PDF 859KB] ( 0 )

中华放射肿瘤学杂志

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Chinese Medical Association

Cancer Hospital of Chinese
　Academy of Medical
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Chinese Journal of Lung
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