The mechanism and clinical research progress on radiotherapy combined with immunotherapy in esophageal cancer / 中华放射肿瘤学杂志

Radiation therapy (RT) is one of main methods of comprehensive treatment of esophageal cancer (EC). It plays a dual role in the immune system and can activate systemic immune response. However, the effect of tumor cytotoxicity induced by RT is limited, and it can induce abscopal effect in combination with immunotherapy (IT). A number of clinical studies have shown the effect and great potential of immune checkpoint inhibitors (ICIs), such as PD-1/L1 antibodies in advanced EC. Besides, RT and ICIs exert a synergistic effect. Currently, multiple ongoing studies related to concurrent radiochemotherapy combined with IT is expected to determine the efficacy of this comprehensive treatment in EC and elucidate the efficiency and cost-effectiveness.

Analysis of patterns of recurrence and prognostic factors in 171 locally advanced gastric cancer patients with radiotherapy and concurrent chemotherapy after radical gastrectomy / 中华放射肿瘤学杂志

Objective:To retrospectively analyze prognostic factors and patterns of recurrence in locally advanced gastric cancer patients receiving chemoradiotherapy (CRT) after radical gastrectomy, aiming to provide reference for postoperative CRT of locally advanced gastric cancer.Methods:Clinical data of 171 patients with curatively resected gastric carcinoma who received postoperative CRT in our hospital between 2008 and 2020 were retrospectively analyzed. The disease-free survival and overall survival (OS) rates were calculated by Kaplan- Meier method. Univariate prognostic analysis was performed by log- rank test. Multivariate prognostic analysis was conducted by Cox model. Results:The median follow-up duration was 63 months. The follow-up rate was 93.6%. 31.0% and 66.7% of the enrolled patients were classified in pathological stage Ⅱ and Ⅲ. The acute grade 3 or 4 gastrointestinal and hematological toxicity rates were 8.8% and 9.9%, respectively. In total, 166 patients completed the entire CRT regimen. No toxicity-related death occurred. Regarding patterns of recurrence, 17 patients had locoregional recurrence, 29 had distant metastasis and 12 had peritoneal metastasis. The 1-, 3-and 5-year overall survival (OS) rates were 83.7%, 66.3%, and 60.0%, while the 1-, 3-and 5-year disease-free survival rates were 75.5%, 62.7%, and 56.5%, respectively. In the multivariate analysis, pathological T stage, perineural invasion and lymph node ratio (LNR) were found to be the independent predictors of OS.Conclusions:Postoperative intensity-modulated radiation therapy and chemotherapy are well tolerated, with acceptable toxicities and encouraging locoregional tumor control and long-term survival. LNR can be used as an independent prognostic indicator for OS. Adjuvant CRT should be considered for all patients with a high risk of locoregional recurrence.

Effect of family-based swallowing training program on swallowing function for patients with head and neck cancer undergoing radiotherapy / 中国康复理论与实践

@#Objective To explore the effect of family swallowing training program on swallowing function in patients with head and neck cancer after radiotherapy. Methods From September, 2020 to September, 2021, 45 patients with head and neck tumors who received radiotherapy in the oncology department of Beidahuang Industry Group General Hospital were randomly divided into control group (n = 23) and observation group (n = 22). Both groups received routine treatment, and the observation group received swallowing training program for 14 weeks at the beginning of radiotherapy, including six weeks of individualized guidance training in hospital and eight weeks of home training after leaving the hospital. The incisors spacing, body mass, Kubota Water Swallowing Test (WST) and Functional Oral Intake Scale (FOIS) were compared at the beginning of training, six weeks and 14 weeks after training. Results At the beginning of training, there was no significant difference in incisor spacing, body mass and the scores of WST and FOIS between two groups (P > 0.05). Six weeks and 14 weeks after training, the incisors spacing, and the scores of WST and FOIS were better in the observation group than in the control group (|Z| > 2.332, P < 0.05). Conclusion Family-based swallowing training program is helpful to improve the limitation of mouth opening and dysphagia caused by radiotherapy. Family-based swallowing training program is simple, safe, economical and highly operable, which is worthy of clinical promotion.

Research progress on accelerated partial breast irradiation for early breast cancer after breast-conserving surgery / 中华放射肿瘤学杂志

Currently, whole breast radiotherapy (WBRT) is the standard treatment for early breast cancer after breast-conserving surgery, which effectively reduces the recurrence rate. Accelerated partial breast irradiation (APBI), a special radiotherapy that only targets the limited volume of tissues surrounding the primary lesion, has attracted more and more attention because of the high proportion of tumor recurrence adjacent to the tumor resection cavity. In recent years, a number of prospective randomized controlled trails have demonstrated its safety and effectiveness, which is a feasible choice for specific low-risk patients after breast-conserving surgery. Compared with WBRT, APBI shortens the treatment time, reduces the treatment cost and improves the cosmetic effect. At the same time, more and more APBI technologies have been developed, which enhance the accessibility and possess unique advantages for partial patients undergoing breast-conserving surgery. Nevertheless, the efficacy and side effects of APBI technologies still differ, which need to be treated differently. In this paper, multiple APBI technologies, research progresses at home and abroad and applicable population were reviewed. The unresolved problems were proposed and development prospect was predicted, aiming to provide reference for clinical application.

Selectively enhancing radiosensitivity of cancer cells

The radiotherapy modulators used in clinic have disadvantages of high toxicity and low selectivity. For the first time, we used the

Prediction of rectal toxicity of radiotherapy for prostate cancer based on multi-modality feature and multi-classifiers / 南方医科大学学报

OBJECTIVE@#To evaluate rectal toxicity of radiotherapy for prostate cancer using a novel predictive model based on multi-modality and multi-classifier fusion.@*METHODS@#We retrospectively collected the clinical data from 44 prostate cancer patients receiving external beam radiation (EBRT), including the treatment data, clinical parameters, planning CT data and the treatment plans. The clinical parameter features and dosimetric features were extracted as two different modality features, and a subset of features was selected to train the 5 base classifiers (SVM, Decision Tree, K-nearest-neighbor, Random forests and XGBoost). To establish the multi-modality and multi-classifier fusion model, a multi-criteria decision-making based weight assignment algorithm was used to assign weights for each base classifier under the same modality. A repeat 5-fold cross-validation and the 4 indexes including the area under ROC curve (AUC), accuracy, sensitivity and specificity were used to evaluate the proposed model. In addition, the proposed model was compared quantitatively with different feature selection methods, different weight allocation algorithms, the model based on single mode single classifier, and two integrated models using other fusion methods.@*RESULTS@#Repeated (5 times) 5-fold cross validation of the proposed model showed an accuracy of 0.78 for distinguishing toxicity from non-toxicity with an AUC of 0.83, a specificity of 0.79 and a sensitivity of 0.76.@*CONCLUSIONS@#Compared with the models based on a single mode or a single classifier and other fusion models, the proposed model can more accurately predict rectal toxicity of radiotherapy for prostate cancer.

Efficacy evaluation of“radiotherapy assistant”application on lung cancer patients / 预防医学

Objective @#To explore the effects of“radiotherapy assistant”application on lung cancer patients who receive radiotherapy.@*Methods @#A total of 120 patients with lung cancer who received radiotherapy in Hangzhou Cancer Hospital from March to September 2017 were recruited and randomly divided into a control group and an experimental group. The patients in the control group received the routine health education,while the ones in the experimental group performed the“radiotherapy assistant”application focused on interactive guidance. Before and after the intervention,the scores of treatment-nursing compliance and self-management efficacy between the two groups were compared. @*Results @#After the intervention,the compliance scores of radiotherapy treatment,health behaviors,regular review,moderate exercise,medication and diets in the experimental group were 2.77±0.43,2.67±0.51,2.68±0.50,2.45±0.75,2.77±0.43 and 2.65±0.55;the ones in the control group were 2.62±0.49,2.42±0.59,2.55±0.50,2.37±0.64,2.67±0.48 and 2.37±0.69. The scores of the six items of compliance in the two groups were all improved compared to the ones before the intervention,but the interaction between the groups and intervention time was not statistically significant（P>0.05）. The scores of positive attitude,self-decompression,self-decision and total self- management efficacy in the experimental group were 52.48±7.69,10.51±3.31,36.88±6.15 and 97.62±12.87,respectively;the ones in the control group were 37.38±10.44,5.70±1.51,27.58±9.41,and 92.17±11.19. The scores of the two groups were all improved compared to the ones before the intervention,and the ranges of the scores improved in the experimental group were wider than those in the control group.@*Conclusion @#The“radiotherapy assistant”application can significantly improve the self-management efficacy of patients who receive the lung cancer radiotherapy,but its effect on the improvement of treatment compliance requires long-term intervention to verify.

When to indicate radiotherapy after nipple-sparing mastectomy? Systematic review / Quando indicar radioterapia após mastectomia nipple-sparing? Revisão sistemática

Introduction: Nipple-sparing mastectomy (NSM) and preservation of the nipple-areola complex (NAC) represent a therapeutic option of breast cancer with a better aesthetic result, a positive impact on body image and more satisfaction than the reconstruction of the NAC. It is questioned the indication of radiotherapy when the NAC is maintained and its potential aesthetic impairment. Objective: To examine the indication of radiotherapy in NSM and, secondarily, the incidence of NAC involvement and local recurrence rates. Methods: Systematic review carried out in the PubMed database with the terms ("breast neoplasm" [Mesh] OR "breast cancer") AND ("radiotherapy" OR "radiation therapy") AND ("nipple sparing mastectomy" OR "mastectomies" OR "subcutaneous mastectomies"). The selection of the studies, the evaluation of its quality and data extraction were carried out independently by four reviewers. Results: The indications for radiotherapy after NSM were: positive axilla, tumors over 5 cm and retroareolar tissue remaining greater than 5 mm. The NAC involvement occurred in 5 to 26.1% in the definitive anatomopathological study. NAC recurrence occurred from 2.59 to 10%. NAC necrosis occurred in 2.2 to 43.4%. Conclusions: The radiotherapy indications for NSM seem to follow the same classical indications for radiotherapy after mastectomy. The relapse index in NAC was not shown to be larger and without difference for the type of radiotherapy used. Radiotherapy should be based on factors that suggest a high risk for NAC involvement

Introdução: A mastectomia nipple-sparing (MNS) e a conservação do complexo aréolo-papilar (CAP) representam uma manobra terapêutica do câncer de mama com melhor resultado estético, impacto positivo na imagem corporal e mais satisfação do que a reconstrução do CAP. Questiona-se a indicação de radioterapia quando da manutenção do CAP e seu potencial prejuízo estético. Objetivo: Examinar a indicação de radioterapia em MNS e, secundariamente, a incidência do envolvimento do CAP e as taxas de recorrência local. Métodos: Revisão sistemática realizada na base de dados do PubMed com os termos ("breast neoplasm" [Mesh] OR "breast cancer") AND ("radiotherapy" OR "radiation therapy") AND ("nipple sparing mastectomy" OR "mastectomies" OR "subcutaneous mastectomies"). A seleção dos estudos, a avaliação da qualidade do estudo e a extração de dados foram realizadas de forma independente por quatro revisores. Resultados: As indicações para radioterapia após MNS foram: axila positiva, tumores acima de 5 cm e tecido retroareolar remanescente maior que 5 mm. O envolvimento do CAP ocorreu em 5 a 26,1% no anatomopatológico definitivo. A recorrência no CAP ocorreu de 2,59 a 10%. A necrose do CAP ocorreu em 2,2 a 43,4%. Conclusão: As indicações de radioterapia para MNS parecem seguir as mesmas indicações clássicas para radioterapia após mastectomia. O índice de recidiva no CAP não mostrou ser maior com uso de radioterapia nem ter diferença quanto ao seu tipo. A decisão de realizar a radioterapia deve se basear em fatores que sugerem alto risco para envolvimento do CAP

Natural radioprotectors and their impact on cancer drug discovery

Cancer is a complex multifaceted illness that affects different patients in discrete ways. For a number of cancers the use of chemotherapy has become standard practice. Chemotherapy is a use of cytostatic drugs to cure cancer. Cytostatic agents not only affect cancer cells but also affect the growth of normal cells; leading to side effects. Because of this, radiotherapy gained importance in treating cancer. Slaughtering of cancerous cells by radiotherapy depends on the radiosensitivity of the tumor cells. Efforts to improve the therapeutic ratio have resulted in the development of compounds that increase the radiosensitivity of tumor cells or protect the normal cells from the effects of radiation. Amifostine is the only chemical radioprotector approved by the US Food and Drug Administration (FDA), but due to its side effect and toxicity, use of this compound was also failed. Hence the use of herbal radioprotectors bearing pharmacological properties is concentrated due to their low toxicity and efficacy. Notably, in silico methods can expedite drug discovery process, to lessen the compounds with unfavorable pharmacological properties at an early stage of drug development. Hence a detailed perspective of these properties, in accordance with their prediction and measurement, are pivotal for a successful identification of radioprotectors by drug discovery process.

How to reduce radiotherapy-induced lung injury in the treatment of non-small cell lung cancer / 中华放射肿瘤学杂志

Radiotherapy is one of the main therapeutic methods of lung cancer, whereas the lung injury induced by radiotherapy restricts the quality of life and clinical efficacy. It is a challenge to improve the clinical efficacy and reduce lung injury.Based upon clinical experience, certain measures can be taken to alleviate the lung injury after thoracic radiotherapy. The severity and complications of lung cancer and the concurrent chemoradiotherapy-induced injury should be comprehensively understood to establish individual therapeutic strategy. The diagnostic skills, biological characteristics of tumors, the diffusion, metastasis and recurrence of tumors and lymphatic drainage should be mastered and considered in the formulation of treatment target areas to minimize unnecessary radiation for every 1 mm. During the formulation and evaluation of radiotherapy plans, we should understand the biological characteristics of the lung and lung injury repair and stick to the principle of high-dose radiation for small-volume lung rather than low-dose radiation for large-volume lung. A better treatment plan should be established to reduce every 1% of lung DVH as possible even at the expanse of conformality. Simultaneous modulated accelerated radiotherapy and two-phase radiotherapy are employed to distinguish normal tissues from subclinical tumors from the dose and fractioned dose aspects, which further enhance the tumor control and alleviate lung injury. The lung ventilation function is lost at a dose of 20 Gy or higher. Extensive attention should be delivered to reduce the radiation dose to the lung, especially for the repair of non-functional lung fibrosis. Precise and individualized radiotherapy should be adopted to reduce unnecessary radiation and protect the normal lung tissues, which improve the clinical efficacy and enhance the quality of life.

Correlation between weight loss and setup errors in intensity-modulated radiotherapy for rectal cancer / 中华放射肿瘤学杂志

Objective To investigate the change in body weight over time in rectal cancer patients receiving radiotherapy and the correlation between setup errors and weight loss,and to establish the image-guided radiotherapy regimens in different periods of treatment.Methods A total of 24 postoperative patients with rectal cancer admitted to our hospital in 2016 were selected.Before each fraction of radiotherapy,the body weight was recorded,and the patients underwent cone-beam computed tomography (CBCT) with different frequencies in every week.The planning CT was matched with CBCT to obtain setup errors.The paired t test was used for difference analysis;the Pearson method was used to analyze the correlation between setup errors and weight loss.Results Body weight was measured 456 times in the 24 patients,and these patients underwent CBCT scans and image registration 456 times.Two patients were excluded because of treatment discontinuance.In the first and second weeks,there was no significant change in body weight.In the third week,the mean weight loss was 1.53 kg.In the fourth week,the mean weight loss was 2.48 kg.In the fifth week,the mean weight loss was 3.24 kg.The setup errors obtained by CBCT image registration in the superior-inferior (SI),anterior-posterior (AP),and left-right (LR) directions were 0.19 cm,0.20 cm,and 0.18 cm,respectively,in the first week,0.18 cm,0.17 cm,and 0.15 cm,respectively,in the second week,0.20 cm,0.22 cm,and 0.21 cm,respectively,in the third week,0.19 cm,0.25 cm,0.24 cm,respectively,in the fourth week,and 0.34 cm,0.33 cm,and 0.31 cm,respectively,in the fifth week.The Pearson correlation analysis showed that weight loss increased the setup errors,with P values of 0.140,0.046,and 0.044 in the SI,AP,and LR directions,respectively.Conclusions For rectal cancer patients receiving radiotherapy,the body weight decreases significantly in the late period (especially in the fifth week),which influences the setup errors.Therefore,in the fourth and fifth weeks of radiotherapy for rectal cancer,the weight loss should be closely monitored,and the number of CBCT scans can be increased before the treatment fraction to ensure the accuracy and optimization of treatment.

Evaluation of plan quality between two treatment planning systems for volumetric modulated arc therapy / 中华放射肿瘤学杂志

Objective To investigate the plan quality between two treatment planning systems (TPSs) for volumetric modulated arc therapy (VMAT). Methods VMAT plans based on Varian Eclipse and Philips Pinnacle TPS were designed for 10 cervical cancer patients (2, 3 Arcs) and 10 prostate cancer patients ( 1, 2 Arcs) . The delivery system of VMAT was Varian ClinaciX machine, and RapidArc was used. The treatment plan quality between the two TPSs was evaluated based on dose distribution, delivery efficiency, and parameter settings. The differences between the two TPSs were compared using paired t-test. Results For cervical cancer patients, the 2-Arc VMAT plans based on the Pinnacle was slightly better than those based on the Eclipse in terms of the conformal index ( CI) of planning target volume ( PTV) , rectum V30 and V40 , and bladder V30 and V40 , and the homogeneity index ( HI) of PTV and PTV1 as well as CI of PTV1 in the Eclips were slightly better than those in the Pinnacle( P<005) Pinnacle were slightly worse than those in the Eclipse ( P>005) . The number of monitor units with 2-Arcs and 3-Arcs plans of the Eclipse was significantly smaller than those in the Pinnacle (P<005). For prostate cancer patients, The 1-arc VMAT plans of the Pinnacle TPS were slightly superior to those of the Eclipse TPS in terms of the HI of PTV, rectumV30 and V40 , and bladderV30 and V40 , but the former was slight inferior to the latter in terms of the CI of PTV (P<005). The number of monitor units of 1-arc and 2-Arcs plans showed no significant difference between the two TPSs (P>005). Conclusions For patients with cervical cancer and prostate cancer, the VMAT plans based on Varian Eclipse and Philips Pinnacle TPS can achieve a clinically acceptable dose distribution and show a little difference in the treatment plan quality. However, we will still need more cases to further study and determine the performance characteristics of the commercial TPSs for optimizing VMAT.

Clinical value of radiotherapy in 78 patients with pT3 N0 M0 breast cancer after modified radical mastectomy / 中华放射肿瘤学杂志

Objective To investigate the value of post-mastectomy radiotherapy ( PMRT ) in patients with T3 N0 breast cancer ( BC ) who were treated with modified radical mastectomy ( MRM ) . Methods A retrospective analysis was performed on the clinical data of BC patients treated with MRM from 1997 to 2014. The inclusion criteria were as follows:( 1 ) female patients;( 2 ) pathological diagnosis of invasive BC;(3) tumor volume greater than 5 cm without axillary lymph node metastasis;(4) the patients who received no neoadjuvant chemotherapy or endocrine therapy and had no distant metastasis or other second primary cancers. A total of 78 patients met the inclusion criteria. Forty patients ( 51%) received PMRT and sixty-seven patients (86%) received adjuvant chemotherapy. The Kaplan-Meier method was used to calculate overall survival ( OS ) , disease-free survival ( DFS ) ( DFS ) , and local-regional recurrence ( LRR) rates, and survival differences between groups were analyzed by the log-rank test. Results The median follow-up time was 79 months ( 6-232 months) . For all patients, the 5-year OS, DFS, and LRR rates were 89%, 87%, and 2%, respectively. The 5-year DFS, OS and LRR rates for radiotherapy group were 84%, 84% and 0%, respectively, versus 91%( P= 0641 ) , 96%( P= 0126 ) , and 5% for non-radiotherapy group. Only estrogen receptor/progesterone receptor ( ER/PR) status and molecular type had significant impacts on DFS ( P=0002 and 0031, respectively) . One patient in non-radiotherapy group had chest wall recurrence. Conclusions MRM is effective in reducing LRR in T3 N0 M0 BC patients. Only ER/PR status and molecular type significantly influence DFS. Effective systemic therapy may be helpful for some T3 N0 patients to avoid chest wall and supraclavicular radiotherapy after MRM, but large-sample studies are needed to further confirm this conclusion.

Evaluation of plan quality between two treatment planning systems for volumetric modulated arc therapy / 中华放射肿瘤学杂志

Objective To investigate the plan quality between two treatment planning systems (TPSs) for volumetric modulated arc therapy (VMAT). Methods VMAT plans based on Varian Eclipse and Philips Pinnacle TPS were designed for 10 cervical cancer patients (2, 3 Arcs) and 10 prostate cancer patients ( 1, 2 Arcs) . The delivery system of VMAT was Varian ClinaciX machine, and RapidArc was used. The treatment plan quality between the two TPSs was evaluated based on dose distribution, delivery efficiency, and parameter settings. The differences between the two TPSs were compared using paired t-test. Results For cervical cancer patients, the 2-Arc VMAT plans based on the Pinnacle was slightly better than those based on the Eclipse in terms of the conformal index ( CI) of planning target volume ( PTV) , rectum V30 and V40 , and bladder V30 and V40 , and the homogeneity index ( HI) of PTV and PTV1 as well as CI of PTV1 in the Eclips were slightly better than those in the Pinnacle( P<005) Pinnacle were slightly worse than those in the Eclipse ( P>005) . The number of monitor units with 2-Arcs and 3-Arcs plans of the Eclipse was significantly smaller than those in the Pinnacle (P<005). For prostate cancer patients, The 1-arc VMAT plans of the Pinnacle TPS were slightly superior to those of the Eclipse TPS in terms of the HI of PTV, rectumV30 and V40 , and bladderV30 and V40 , but the former was slight inferior to the latter in terms of the CI of PTV (P<005). The number of monitor units of 1-arc and 2-Arcs plans showed no significant difference between the two TPSs (P>005). Conclusions For patients with cervical cancer and prostate cancer, the VMAT plans based on Varian Eclipse and Philips Pinnacle TPS can achieve a clinically acceptable dose distribution and show a little difference in the treatment plan quality. However, we will still need more cases to further study and determine the performance characteristics of the commercial TPSs for optimizing VMAT.

Clinical value of radiotherapy in 78 patients with pT3 N0 M0 breast cancer after modified radical mastectomy / 中华放射肿瘤学杂志

Objective To investigate the value of post-mastectomy radiotherapy ( PMRT ) in patients with T3 N0 breast cancer ( BC ) who were treated with modified radical mastectomy ( MRM ) . Methods A retrospective analysis was performed on the clinical data of BC patients treated with MRM from 1997 to 2014. The inclusion criteria were as follows:( 1 ) female patients;( 2 ) pathological diagnosis of invasive BC;(3) tumor volume greater than 5 cm without axillary lymph node metastasis;(4) the patients who received no neoadjuvant chemotherapy or endocrine therapy and had no distant metastasis or other second primary cancers. A total of 78 patients met the inclusion criteria. Forty patients ( 51%) received PMRT and sixty-seven patients (86%) received adjuvant chemotherapy. The Kaplan-Meier method was used to calculate overall survival ( OS ) , disease-free survival ( DFS ) ( DFS ) , and local-regional recurrence ( LRR) rates, and survival differences between groups were analyzed by the log-rank test. Results The median follow-up time was 79 months ( 6-232 months) . For all patients, the 5-year OS, DFS, and LRR rates were 89%, 87%, and 2%, respectively. The 5-year DFS, OS and LRR rates for radiotherapy group were 84%, 84% and 0%, respectively, versus 91%( P= 0641 ) , 96%( P= 0126 ) , and 5% for non-radiotherapy group. Only estrogen receptor/progesterone receptor ( ER/PR) status and molecular type had significant impacts on DFS ( P=0002 and 0031, respectively) . One patient in non-radiotherapy group had chest wall recurrence. Conclusions MRM is effective in reducing LRR in T3 N0 M0 BC patients. Only ER/PR status and molecular type significantly influence DFS. Effective systemic therapy may be helpful for some T3 N0 patients to avoid chest wall and supraclavicular radiotherapy after MRM, but large-sample studies are needed to further confirm this conclusion.

A study of lung protection in intensity?modulated radiotherapy with split field and fixed jaw techniques for peripheral lung cancer with mediastinal lymph node metastasis / 中华放射肿瘤学杂志

Objective To retrospectively design an intensity?modulated radiotherapy ( IMRT) plan with split field and fixed jaw techniques for peripheral lung cancer with mediastinal lymph node metastasis, to compare dosimetric characteristics between the IMRT plans with fixed jaw and dynamic jaw, and to study lung protection by the plan with split field and fixed jaw. Methods Treatment plans were collected from 12 patients with peripheral lung cancer and mediastinal lymph node metastasis who were treated with IMRT in our hospital. All plans used the dynamic jaw technique. The plans with split field and fixed jaw were designed based on the identical computed tomography images and planning target volume ( PTV) . Each jaw position in split field depended on each separate PTV. The prescription dose was 60 Gy in 30 fractions. 95%PTV was planned to receive 100% of the prescription dose. Dosimetric parameters of PTV, conformity index ( CI) , heterogeneity index ( HI) , number of monitor units ( MUs) , and dose?volume values of the lung and heart were obtained from dose?volume histogram. Comparison between the two plans was made by paired t test. Results Both plans met clinical requirements. There were no significant differences in D2 , D98 , CI, or HI of PTV between the two plans ( all P>005) . Compared with the dynamic jaw plan, the fixed jaw plan had MUs increased by 15%?20%( P=0010) . The V5 , V10 , V20 , V30 , and mean dose for the whole lungs were significantly lower in the fixed jaw plan than in the dynamic jaw plan ( P=0000, 0000, 0000, 0002,0000) . The V5 , V20 , and mean dose for the healthy lung were also significantly lower in the fixed jaw plan than in the dynamic jaw plan ( P=0000,0017,0000) . There were no significant differences in dose?volume values for the spinal cord or heart between the two plans ( all P>005) . Conclusions IMRT with split field and fixed jaw is recommended for patients with peripheral lung cancer and mediastinal lymph node metastasis. The therapy to a certain extent reduces low?dose volume for the lung and the incidence of radiation?induced pneumonitis.

Applications of Low Energy Megavoltage X-ray Beams in Cancer Radiotherapy.

A review on the applications of low energy megavoltage (MV) X-ray beams (1-4 MV) in cancer radiotherapy is presented. Firstly, the physical characteristics of low energy megavoltage X-ray beams are reviewed in terms of penumbra, dose fall-off, exit dose, dose to bone, penetration power, skin dose and image quality. Secondly, the therapeutic applications of low energy megavoltage X-rays in cancer radiotherapy are further stratified and discussed based on X-ray energy levels. Thirdly, a systematic review of imaging applications of low energy megavoltage Xray beams in image-guided radiation therapy (IGRT) and megavoltage fan beam computed tomography (MVFBCT) is provided. Finally, we summarize the latest development of low energy megavoltage X-ray beams in cancer radiotherapy and cancer imaging during the past twenty years. With their intrinsic physical characteristics, it is feasible to achieve personalized radiotherapy and personalized imaging protocols for individual patient. However, further technological developments and more clinical data would be needed to fully exploit the potentials of low energy megavoltage X-ray beams in the personalized radiotherapeutic management of cancers.

Dosimetric comparison between helical tomotherapy and step-and-shoot intensity modulated radiation therapy for cervix carcinoma / 中华放射医学与防护杂志

Objective To compare the dosimetric characteristics of helical tomotherapy(HT)and step-and-shoot intensity modulated radiotherapy(IMRT)for post-operative cervix cancer patients. Methods Ten patients with post-operative cervix cancer were enrolled in this study.HT and IMRT plans were developed for each patient.The dose distributions of the targets,organs at risk(OARs),CI and HI were analyzed and compared.The prescribed dose was 60 Gy/25 f for CTV1,50 Gy/25 f for CTV2.The iso-dose line of 50 Gy was used.Results The homogeneity indexes(HI)(0.94±0.03),conformity index(C1)(1.28±0.02)in HT group were better than in IMRT group(0.85±0.01 and 1.36±0.03),respectively(t=5.12,-6.34,P<0.001).The Dmean of PTV in HT group(51.77 Gy)was lower than that in IMRT group(54.53 Gy)(t=-8.01,P<0.05).The Dmax ,Dmean,V30,V40 and V50 of bladder、rectum and small bowel were lower in HT group than those in IM RT group.The Dmax,Dmean,V30 and V40 of right and left femoral head were lower in HT group than those in IMRT group.Conclusion Helical tomotherapy treatment plan has a better homogeneity,steeper dose gradient,and a better protection for organs at risk.

Optimization of registration template of cone-beam CT guided whole breast irradiation after lumpectomy of breast cancer / 中华放射医学与防护杂志

Objective To optimize the registration template of kilovohage cone-beam CT (CBCT) guided radiotherapy in whole breast irradiation(WBI)after lumpectomy of breast cancer.Methods From April 2006 to July 2009,twelve patients undergoing WBI with intensity-modulated radiotherapy (IMRT)were recruited in this study.All patients were performed with both conventional planning CT and CBCT integrated on Varian 23 EX.Six distinguishable referenee points(the diameter 1 mm)around the lumpectomy cavity and the surrounding gland on the planning CT image were marked.The images were manually registered offline based on the breast surface,surgical clips,breast gland,contiguous rib,ipsilaterai lung and its external contours,respectively.The same six reference points were then marked on the CBCT image.The performance of the five registration templates was compared using the concept of registration error,while the registration time was taken into account.The registration error was calculated based on the six reference points'translations between the planning CT image and CBCT image,and analyzed with SPSS 13.0 software using one-way ANOVA.Results The values of the registration error for the breast surface,surgical clips,breast gland, contiguous rib,ipsilateral lung and its external contours were(0.60±0.20),(0.43±0.15),(0.49±0.19),(0.69±0.36)and(0.94±0.49)cm,respectively,and the registration time were(3.8±1.1),(3.0±0.9),(4.7±1.7),(4.3±1.3)and(4.5±1.3)min,respectively.There was no statistical difforence between the breast surface,surgical clips and breast gland registration template(t=0.48-1.36,P>0.05),the same result trend to contiguous rib compared with ipsilateral lung(t=2.00,P=0.055),however,there was significant difference between surgical clips and the last two registration methods(t=2.08-4.08,P<0.05).Conclusion In this initial study with a modest number of patients,surgical clips show a best registration template from the standpoint of accuracy and efficiency,whereas contiguous rib and ipsilateral lung are not an ideal method.

Probabilities of Pulmonary and Cardiac Complications and Radiographic Parameters in Breast Cancer Radiotherapy / 대한방사선종양학회지

PURPOSE: To evaluate the relationship between the normal tissue complication probability (NTCP) of 3- dimensional (3-D) radiotherapy and the radiographic parameters of 2-dimensional (2-D) radiotherapy such as central lung distance (CLD) and maximal heart distance (MHD). MATERIALS AND METHODS: We analyzed 110 patients who were treated with postoperative radiotherapy for breast cancer. A two-field tangential technique, a three-field technique, and the reverse hockey stick method were used. The radiation dose administered to whole breast or the chest wall was 50.4 Gy, whereas a 45 Gy was administered to the supraclavicular field. The NTCPs of the heart and lung were calculated by the modified Lyman model and the relative seriality model. RESULTS: For all patients, the NTCPs of radiation-induced pneumonitis and cardiac mortality were 0.5% and 0.7%, respectively. The NTCP of radiation-induced pneumonitis was higher in patients treated with the reverse hockey stick method than in those treated by other two techniques (0.0%, 0.0%, 3.1%, p<0.001). The NTCP of radiation-induced pneumonitis increased with CLD. The NTCP of cardiac mortality increased with MHD (R2=0.808). CONCLUSION: We found a close correlation between the NTCP of 3-D radiotherapy and 2-D radiographic parameters. Our results are useful to reanalyze the previous 2-D based clinical reports about breast radiation therapy complications as a viewpoint of NTCP.