Objective To explore the influence of dose rate reference control level on the design of accelerator shielding.Methods According to the standards of GBZ 126-2011,GBZ/T 201.1-2007 and GBZ/T 201.2-2011,two different shielding calculation methods,based on the dose rate reference control level and week dose control level,were used to calculate and compare the thickness of accelerator room shielding.Results Under the same condition of maximum weekly workload,the obtained results were different when the calculated dose rate reference control value was larger than dose rate reference control level (2.5 μSv/h).The maximum difference of shielding thickness reached 64 cm.Meanwhile,considering dose rate reference control level,the different accelerator rates could lead to different radiation shielding thickness.Conclusions The dose rate at reference point must be first calculated before calculating shielding thickness.The calculation should be made on the premise that dose rate reference control level is met.

ObjectiveTo compare the accuracy of enhanced dynamic wedge (EDW) models of adaptive convolution algorithm (ACA) in Pinnacle3 9.0 and anisotropic analytical algorithm (AAA),and pencil beam convolution (PBC) algorithms in Eclipse7.3 treatment planning systems (TPS).MethodsTo evaluate the accuracy of the three algorithm models,we compared actual measurement values with TPS calculation values of EDW wedge factors under for different fields in which Varian-21EX 6 MV X-ray was applied,and also compared the actual dose distribution profile with that of TPS.ResultsThe deviations of EDW wedge factors of symmetry fields and asymmetric fields are within 2.8％ and 19.4％ for ACA in Pinnacle3 9.0.Meanwhile,the deviations are 1.0％ and 2.0％ for AAA,1.2％ and 3.0％ for PBC in Eclipse7.3.The deviations between measurement and calculation of all fields profile for ACA is within 3％ and within 2.7％ for AAA within 4.0％ for PBC in wedge direction.For the dose distributions,we evaluated the pass rates of three algorithms using gamma analysis.The gamma pass rates among all the three algorithms in symmetry and asymmetric fields are above 87％ and 85％ respectively.After the removal of the penumbra zone,the pass rates among all the three algorithms are above 96％ in symmetry fields,and above 95％ in asymmetric fields,respectively.Conclusions AAA and PBC algorithms in symmetric and asymmetric fields can meet the need of clinical applications.While,wedge factor of ACA should not be used in clinical due to its greater error in asymmetric fields.

Objective To study how to design the treatment plan to reduce the influence of respiratory movement and the dose of heart and lung as few as possible,to improve the dosage distribution in the target area after radical mastectomy of breast cancer.Methods Twelve patients with breast cancer after radical mastectomy were selected.A dose of 50 Gy with 2 Gy every day and 5 times per week was prescribed.Based on the treatment planning system (TPS),4-field intensity modulated radiotherapy (4FIMRT) and hybrid intensity modulated treatment planning 2-field conformal radiotherapy (2FCRT) + 4FIMRT were designed respectively.The two plans were compared from the aspects of target conformity index (CI),the homogeneity index (HI) and exposure dose volume delivered to organ at risk.Results According to the hybrid plan of 2FCRT + 4FIMRT,HI was 1.08±0.01,which was superior to that from 4FIMRT (1.11±0.01,t =9.587,P ＜ 0.05).While CI was 0.74±0.08,based on the plan of 2FCRT+4FIMRT,which was slightly lower than that from 4FIMRT (0.80±0.03,t =2.497,P ＜ 0.05).Considering the dose volumes on ipsilateral lung in two plans,the values of V5,V10,Dmean of 2FCRT+4FIMRT plan were significantly less than those of 4FIMRT plan.V5,V10,Dmean from the former plan were 13 ％,23 ％,7 ％ less than those from the latter plan (t =6.002,P ＜ 0.05;t =6.826,P ＜ 0.05;t =3.645,P ＜ 0.05).Meanwhile,Dmean of contralateral lung,Dmean of heart,Dmean and V5 of contralateral breast from the 2FCRT +4FIMRT plan were all lower than those of 4FIMRT plan.Those differences between two plans were statistically significant (P ＜ 0.05).Differences of V20 and V30 of ipsilateral lung,and V30 of heart between two plans did not make sense by the statistics analysis (P ＞ 0.05).Conclusion Hybrid radiotherapy theoretically reduces the influence of respiratory movement,improves the uniformity of target dose and lowers the risk of complications of radiation therapy on breast cancer.

Objective To compare the dosimetric differences between two plans of RapidArc and 5F-IMRT for breast cancer radiotherapy after breast-conserving surgery.Methods Eight female patients with left-sided breast cancer after breast-conserving surgery were selected.A dose of 50 Gy in 25 fractions was prescribed for plans of RapidArc and 5F-IMRT.Target conformity index (CI),homogeneity index (HI),target coverage,exposure dose volume delivered to organ at risk were compared between two plans.At the same time,treatment delivery time and monitor units (MU) were also compared.Results The target conformity index (CI) in RapidArc plan (·0.88 ±0.03) was higher than that in 5F-IMRT plan (0.79 ±0.02,t =8.28,P ＜ 0.05).The homogeneity index (HI) in RapidArc plan 9.01 ± 0.73 was significantly lower than that in 5F-IMRT plan10.44 ± 1.08 (t =-2.73,P ＜0.05).For the dose volume delivered to the ipsilateral lung in two plans,the values of V10,V20,V30,and Dmean in RapidArc plan were lower than those in 5F-IMRT plan(t =-7.53,-7.20,-8.39,-7.80,P ＜ 0.05).However,the value of V5 in RapidArc plan was higher than that in 5F-IMRT plan (t =5.67,P ＜0.05).For the heart,the values of V5,V10 and Dmean in RapidArc plan were higher than those in IMRT plan(t =10.46,28.76,5.40,P ＜ 0.05),while the value of V30 in RapidArc plan was lower than that in 5F-IMRT plan(t =-6.12,P ＜0.05).The values of V5 in contralateral lung and breast were higher in RapidArc plan than those in 5F-IMRT plan(lung:t =21.50,P ＜0.05;breast:t =5.44,P ＜0.05).The MU in RapidArc plan was decreased by 25％,and the average treatment delivery time was saved by 60％,compared with that of 5F-IMRT plan.Conclusions During breast cancer radiotherapy after breast-conserving surgery,compared with 5F-IMRT plan,the RapidArc plan could improve the target HI,and reduce both the irradiated dose in high-dose volume and MU,and shorten the treatment time,but increased the exposed volume in low-dose volume of normal tissues.

Objective To investigate the feasibility and potential advantages of RapidArc applied to the radiotherapy of the postoperative rectal cancer.Methods 8 postoperative patients with rectal cancer were selected to be treated with a dose of 50Gy in fraction of 2Gy every time and 5 times a week.IMRT and RapidArc were used respectively to compare different target conformities,homogeneity index,dose-volume histogram data,treatment times and monitor units.Results The conformal index by RapidArc was 0.89±0.02 which was better than those by 5F-IMRT,0.87±0.02 (t =3.286,P ＜ 0.05),while the homogeneity index of target volume (1.060±0.005) and average dose [(52.55±0.76) Gy] by RapidArc were a little less than the homogeneity index of target volume (1.064±0.007) and average dose [(52.90±0.82) Gy] by 5F-IMRT (t =-1.459,-1.000,P ＞ 0.05).The exposure dose and mean dose of bladder and small bowel in high dose region by RapidArc were lower than those by 5F-IMRT,as well as bone marrow.The differences were statistical significant (P ＜ 0.05).The monitor units by RapidArc and by 5F-IMRT were (631±68) MU and (1046±146) MU,respectively (t =-5.830,P ＜ 0.05),while the mean treatment times were (78±5) s and (348±29) s,respectively (t =-26.358,P ＜ 0.05).Conclusion Compared with 5F-IMRT,RapidArc improves the target conformities and lowers the exposure dose for the organs at risk in high dose region while using fewer monitor units and less treatment time,which helps comforting patients and improving the efficiency.

Objective: To investigate the perioperative weight loss and its influencing factors in patients with colorectal cancer, and to provide evidence for the development and management of perioperative nutritional support strategies. Methods: Ninety-one patients with colorectal cancer were enrolled and divided into observation group (n=61) with the degree of weight loss less than 5% of preoperative weight and control group (n=30) with the degree of weight loss more than 5% of preoperative weight. Change of body composition and factors of weight loss in patients with colorectal cancer were compared between the two groups by single factor and multivariate analysis. Results: Ninety-one patients with colorectal cancer had the average weight loss of 2.0 kg. Of perioperative changes in body composition, the degree of body fat, muscle mass and protein group decreased statistically (P<0.05). Univariate analysis showed that the age, intraoperative blood loss and postoperative oral nutrition intake compliance were the risk factors for the degree of weight loss in patients with colorectal cancer after the operation. Multivariate logistic regression analysis showed that the intraoperative blood loss was an independent influencing factor for the degree of postoperative weight loss in patients with colorectal cancer (P<0.05). Conclusion Age, intraoperative blood loss and postoperative oral nutritional intake compliance may affect the degree of weight loss during perioperative period. Intraoperative blood loss is an independent risk factor affecting the degree of weight loss during perioperative period. In future clinical research and practice, minimally invasive and accurate surgical treatment should be strengthened, the amount of intraoperative blood loss and surgical trauma should be reduced, and the postoperative oral nutrition intake of patients should be paid attention, especially for elderly patients. Personalized dietary guidance and management for different groups should be conducted, and perioperative nutritional status of patients should be improved.

Objective:To investigate the nutrition researches in radiation oncology, identify the hot topics, and inform the future development of radiotherapy nutrition.Method:Web of Science Core Collection was searched and Citespace-based analysis was performed for the bibliometric analysis of research papers on tumor radiotherapy nutrition.Results:A total of 1 243 articles were included, and there was an increasing trend in the annual number of articles published from 2014 to 2021. The top three countries with the most publications were the United States, China and Australia. In addition to radiotherapy, tumor and nutrition, common keywords in these articles included quality of life, weight loss, head and neck cancer, parenteral nutrition, enteral nutrition, and dietary intake.Conclusions:Domestic and foreign scholars have paid more and more attention to tumor radiotherapy nutrition. In recent years, the research hot topics are mainly head and neck tumors, nutritional support methods, concurrent chemoradiotherapy and patient prognosis. There was a scarcity of collaborations between domestic and foreign institutions. Institutions such as the State Key Laboratory in Oncology in South China, Sun Yat-sen University and Peking University have been continuously advancing the development of radiotherapy nutrition and have carried out a lot of researches. The gap between China and abroad is narrowing. Researches in China needs to be improved in terms of the depth and breadth. In the future, nutrition researches can further explore the aspects such as experimental protocol publication and the correlation of psychology and nutrition, strengthen international collaboration, and enhance international impact with high-quality publications.

OBJECTIVETo analyze pupils' neglect status aged 6-11 years in China's rural.

METHODSAccording to the principle of multi-stage stratified cluster sampling, to extract 7,943 pupils aged 6-11 years for the survey from 56 primary schools in 28 counties in nine provinces, from December 2012 to March 2013. Proceed questionnaire survey by the scale from "Neglect Evaluation Norms for pupils aged 6-8 years in Rural Areas of China" and "Neglect Evaluation Norms for pupils aged 9-11 years in Rural Areas of China". And analyze neglect rates and neglect degrees of the different grades, gender, family types and different levels of neglect.

RESULTSThe total neglect rate of China's rural pupils aged 6-8 and 9-11 years was 40.2% (1,258/3,130) and 42.5% (1,498/3,526) respectively, which differences had no statistical significant (χ2=3.59, P=0.058); the total neglect degree was 46.04±8.87 and 44.78±10.43 respectively, which differences had statistical significant (t=5.01, P<0.001); the differences of neglect rates and neglect degrees between male (41.4% (657/1,587) and 46.28±8.76) and female (39.0% (601/1,543) and 45.78±8.97) of aged 6-8 were all no statistical significant (χ2=1.87, P=0.171; t=1.49, P=0.136); the neglect rates and neglect degrees of male (46.3% (816/1,763) and 45.53±10.11) were higher than female (38.7% (682/1,763) and 44.06±10.69) in the group of aged 9-11, which differences were all statistical significant (χ2=20.84, t=3.97, P<0.001); the male neglect rate in the group of aged 6-8 in social neglect (11.7% (198/1,691)) and the neglect degree in educational neglect (48.09±9.70) were higher than female (9.4% (155/1,648) and 47.37±9.89), which differences were all statistical significance (χ2=14.55, P<0.001, t=2.22, P=0.026), the male neglect rate in the group of aged 9-11 in physical neglect (20.4% (398/1,954)) was higher than female (16.7% (326/1 957)), which differences had statistical significance (χ2=8.92, P=0.003).

CONCLUSIONThe neglect status of Chinese pupils aged 6-11 years in rural was serious, and we should find out risk factors and provide efficient prevention measures.

Child ; Child Abuse ; China ; Female ; Humans ; Male ; Physical Examination ; Pupil ; Risk Factors ; Rural Population ; Schools ; Surveys and Questionnaires