1. Verification of doses to PTV and OAR and 2D dose distribution in IMRT for 8 accelerators in Henan province
Chuanpeng HU ; Chenzhi JIA ; Kunjie WEI ; Xian XUE ; Zhijian HE ; Suming LUO
Chinese Journal of Radiological Medicine and Protection 2020;40(2):140-144
Objective:
To use TLDs and radiochromic films to verify the prescribed doses to both planned target volume (PTV) and organ at risk (OAR) and the 2D dose distribution in IMRT.
Methods:
Eight accelerators of different models were selected in Henan province. The polystyrene phantom provided by IAEA was scanned using CT scanners and then the scanned images were transmitted to treatment planning system (TPS) for prescribing respectively the doses to PTV and OAR. IMRT was performed with phantom exposed to a 6 MV X-rays. The irradiated TLDs and films were delivered for measurement and estimation at Secondary Standard Dosimetry Laboratory at National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention.
Results:
According to IAEA requirements, the relative deviations of the TLD-measured and TPS-planned values were within ±7.0% for the prescribed doses to PTV and OAR. The measured results for PTV have shown that the relative deviation of TLD-measured and TPS-planned values were within -0.3% to 6.9% for 8 accelerators, all consistent with the IAEA requirements. For OAR, the relative deviations of TLD-measured and TPS-planned were within -7.0% to 0.3% for 6 accelerators, consistent with the requirements, whereas those for other 2 accelerators were within -10.8% to -8.4%, not up to the requirements. IAEA required that, for 2D dose distribution, the pass rate of 3 mm/3% be ≥90%. The measured values for 7 accelerators were from 90.2% to 99.9%, consistent with the requirements, whereas that for another one was 70.0%, not meeting the requirement.
Conclusions
The method to verify, using radiochromic film and TLD, the prescribed doses to PTV and OAR and the pass rate of 2D dose distribution is simple and reliable. It is an important step to implement quality control for IMRT and can provide effective support for medical or third-party service institution to verify clinically prescribed dose.
2.Surgical site infection after abdominal surgery in China: a multicenter cross-sectional study
Xufei ZHANG ; Jun CHEN ; Peige WANG ; Suming LUO ; Naxin LIU ; Xuemin LI ; Xianli HE ; Yi WANG ; Xiaogang BI ; Ping ZHANG ; Yong WANG ; Zhongchuan LV ; Bo ZHOU ; Wei MAI ; Hua WU ; Yang HU ; Daorong WANG ; Fuwen LUO ; Ligang XIA ; Jiajun LAI ; Dongming ZHANG ; Qian WANG ; Gang HAN ; Xiuwen WU ; Jian'an REN
Chinese Journal of Gastrointestinal Surgery 2020;23(11):1036-1042
Objective:Surgical site infection (SSI) can markedly prolong postoperative hospital stay, aggravate the burden on patients and society, even endanger the life of patients. This study aims to investigate the national incidence of SSI following abdominal surgery and to analyze the related risk factors in order to provide reference for the control and prevention of SSI following abdominal surgery.Methods:A multicenter cross-sectional study was conducted. Clinical data of all the adult patients undergoing abdominal surgery in 68 hospitals across the country from June 1 to 30, 2020 were collected, including demographic characteristics, clinical parameters during the perioperative period, and the results of microbial culture of infected incisions. The primary outcome was the incidence of SSI within postoperative 30 days, and the secondary outcomes were ICU stay, postoperative hospital stay, cost of hospitalization and the mortality within postoperative 30-day. Multivariable logistic regression was used to analyze risk factors of SSI after abdominal surgery.Results:A total of 5560 patients undergoing abdominal surgery were included, and 163 cases (2.9%) developed SSI after surgery, including 98 cases (60.1%) with organ/space infections, 19 cases (11.7%) with deep incisional infections, and 46 cases (28.2%) with superficial incisional infections. The results from microbial culture showed that Escherichia coli was the main pathogen of SSI. Multivariate analysis revealed hypertension (OR=1.792, 95% CI: 1.194-2.687, P=0.005), small intestine as surgical site (OR=6.911, 95% CI: 1.846-25.878, P=0.004), surgical duration (OR=1.002, 95% CI: 1.001-1.003, P<0.001), and surgical incision grade (contaminated incision: OR=3.212, 95% CI: 1.495-6.903, P=0.003; Infection incision: OR=11.562, 95%CI: 3.777-35.391, P<0.001) were risk factors for SSI, while laparoscopic or robotic surgery (OR=0.564, 95%CI: 0.376-0.846, P=0.006) and increased preoperative albumin level (OR=0.920, 95%CI: 0.888-0.952, P<0.001) were protective factors for SSI. In addition, as compared to non-SSI patients, the SSI patients had significantly higher rate of ICU stay [26.4% (43/163) vs. 9.5% (514/5397), χ 2=54.999, P<0.001] and mortality within postoperative 30-day [1.84% (3/163) vs.0.01% (5/5397), χ 2=33.642, P<0.001], longer ICU stay (median: 0 vs. 0, U=518 414, P<0.001), postoperative hospital stay (median: 17 days vs. 7 days, U=656 386, P<0.001), and total duration of hospitalization (median: 25 days vs. 12 days, U=648 129, P<0.001), and higher hospitalization costs (median: 71 000 yuan vs. 39 000 yuan, U=557 966, P<0.001). Conclusions:The incidence of SSI after abdominal surgery is 2.9%. In order to reduce the incidence of postoperative SSI, hypoproteinemia should be corrected before surgery, laparoscopic or robotic surgery should be selected when feasible, and the operating time should be minimized. More attentions should be paid and nursing should be strengthened for those patients with hypertension, small bowel surgery and seriously contaminated incision during the perioperative period.
3.Risk factors for surgical site infection after emergency abdominal surgery: a multicenter cross-sectional study in China
Ze LI ; Junru GAO ; Li SONG ; Peige WANG ; Jian'an REN ; Xiuwen WU ; Suming LUO ; Qingjun ZENG ; Yanhong WENG ; Xinjian XU ; Qingzhong YUAN ; Jie ZHAO ; Nansheng LIAO ; Wei MAI ; Feng WANG ; Hui CAO ; Shichen WANG ; Gang HAN ; Daorong WANG ; Hao WANG ; Jun ZHANG ; Hao ZHANG ; Dongming ZHANG ; Weishun LIAO ; Wanwen ZHAO ; Wei LI ; Peng CUI ; Xin CHEN ; Haiyang ZHANG ; Tao YANG ; Lie WANG ; Yongshun GAO ; Jiang LI ; Jianjun WU ; Wei ZHOU ; Zejian LYU ; Jian FANG
Chinese Journal of Gastrointestinal Surgery 2020;23(11):1043-1050
Objective:Surgical site infection (SSI) is the most common infectious complication after emergency abdominal surgery (EAS). To a large extent, most SSI can be prevented, but there are few relevant studies in China. This study mainly investigated the current situation of SSI occurrence after EAS in China, and further explored risk factors for SSI occurrence.Methods:Multi-center cross-sectional study was conducted. Clinical data of patients undergoing EAS in 33 hospitals across China between May 1, 2019 and June 7, 2019 were prospectively collected, including perioperative data and microbial culture results from infected incisions. The primary outcome was the incidence of SSI after EAS, while the secondary outcomes were postoperative hospital stay, ICU occupancy rate, length of ICU stay, hospitalization cost, and mortality within postoperative 30 days. Univariate and multivariate logistic regression models were used to analyze the risk factors of SSI after EAS.Results:A total of 660 EAS patients aged (47.9±18.3) years were enrolled in this study, including 56.5% of males (373/660). Forty-nine (7.4%) patients developed postoperative SSI. The main pathogen of SSI was Escherichia coli [culture positive rate was 32.7% (16/49)]. As compared to patients without SSI, those with SSI were more likely to be older (median 56 years vs. 46 years, U=19 973.5, P<0.001), male [71.4% (35/49) vs. 56.1% (343/611), χ 2=4.334, P=0.037] and diabetes [14.3% (7/49) vs. 5.1% (31/611), χ 2=5.498, P=0.015]; with-lower preoperative hemoglobin (median: 122.0 g/L vs. 143.5 g/L, U=11 471.5, P=0.006) and albumin (median: 35.5 g/L vs. 40.8 g/L, U=9452.0, P<0.001), with higher blood glucose (median: 6.9 mmol/L vs. 6.0 mmol/L, U=17 754.5, P<0.001); with intestinal obstruction [32.7% (16/49) vs. 9.2% (56/611), χ 2=25.749, P<0.001], with ASA score 3-4 [42.9% (21/49) vs. 13.9% (85/611), χ 2=25.563, P<0.001] and with high surgical risk [49.0% (24/49) vs. 7.0% (43/611), χ 2=105.301, P<0.001]. The main operative procedure resulting in SSI was laparotomy [81.6%(40/49) vs. 35.7%(218/611), χ 2=40.232, P<0.001]. Patients with SSI experienced significantly longer operation time (median: 150 minutes vs. 75 minutes, U=25 183.5, P<0.001). In terms of clinical outcome, higher ICU occupancy rate [51.0% (25/49) vs. 19.5% (119/611), χ 2=26.461, P<0.001], more hospitalization costs (median: 44 000 yuan vs. 15 000 yuan, U=24 660.0, P<0.001), longer postoperative hospital stay (median: 10 days vs. 5 days, U=23 100.0, P<0.001) and longer ICU occupancy time (median: 0 days vs. 0 days, U=19 541.5, P<0.001) were found in the SSI group. Multivariate logistic regression analysis showed that the elderly (OR=3.253, 95% CI: 1.178-8.985, P=0.023), colorectal surgery (OR=9.156, 95% CI: 3.655-22.937, P<0.001) and longer operation time (OR=15.912, 95% CI:6.858-36.916, P<0.001) were independent risk factors of SSI, while the laparoscopic surgery (OR=0.288, 95% CI: 0.119-0.694, P=0.006) was an independent protective factor for SSI. Conclusions:For patients undergoing EAS, attention should be paid to middle-aged and elderly patients and those of colorectal surgery. Laparoscopic surgery should be adopted when feasible and the operation time should be minimized, so as to reduce the incidence of SSI and to reduce the burden on patients and medical institutions.
4.Surgical site infection after abdominal surgery in China: a multicenter cross-sectional study
Xufei ZHANG ; Jun CHEN ; Peige WANG ; Suming LUO ; Naxin LIU ; Xuemin LI ; Xianli HE ; Yi WANG ; Xiaogang BI ; Ping ZHANG ; Yong WANG ; Zhongchuan LV ; Bo ZHOU ; Wei MAI ; Hua WU ; Yang HU ; Daorong WANG ; Fuwen LUO ; Ligang XIA ; Jiajun LAI ; Dongming ZHANG ; Qian WANG ; Gang HAN ; Xiuwen WU ; Jian'an REN
Chinese Journal of Gastrointestinal Surgery 2020;23(11):1036-1042
Objective:Surgical site infection (SSI) can markedly prolong postoperative hospital stay, aggravate the burden on patients and society, even endanger the life of patients. This study aims to investigate the national incidence of SSI following abdominal surgery and to analyze the related risk factors in order to provide reference for the control and prevention of SSI following abdominal surgery.Methods:A multicenter cross-sectional study was conducted. Clinical data of all the adult patients undergoing abdominal surgery in 68 hospitals across the country from June 1 to 30, 2020 were collected, including demographic characteristics, clinical parameters during the perioperative period, and the results of microbial culture of infected incisions. The primary outcome was the incidence of SSI within postoperative 30 days, and the secondary outcomes were ICU stay, postoperative hospital stay, cost of hospitalization and the mortality within postoperative 30-day. Multivariable logistic regression was used to analyze risk factors of SSI after abdominal surgery.Results:A total of 5560 patients undergoing abdominal surgery were included, and 163 cases (2.9%) developed SSI after surgery, including 98 cases (60.1%) with organ/space infections, 19 cases (11.7%) with deep incisional infections, and 46 cases (28.2%) with superficial incisional infections. The results from microbial culture showed that Escherichia coli was the main pathogen of SSI. Multivariate analysis revealed hypertension (OR=1.792, 95% CI: 1.194-2.687, P=0.005), small intestine as surgical site (OR=6.911, 95% CI: 1.846-25.878, P=0.004), surgical duration (OR=1.002, 95% CI: 1.001-1.003, P<0.001), and surgical incision grade (contaminated incision: OR=3.212, 95% CI: 1.495-6.903, P=0.003; Infection incision: OR=11.562, 95%CI: 3.777-35.391, P<0.001) were risk factors for SSI, while laparoscopic or robotic surgery (OR=0.564, 95%CI: 0.376-0.846, P=0.006) and increased preoperative albumin level (OR=0.920, 95%CI: 0.888-0.952, P<0.001) were protective factors for SSI. In addition, as compared to non-SSI patients, the SSI patients had significantly higher rate of ICU stay [26.4% (43/163) vs. 9.5% (514/5397), χ 2=54.999, P<0.001] and mortality within postoperative 30-day [1.84% (3/163) vs.0.01% (5/5397), χ 2=33.642, P<0.001], longer ICU stay (median: 0 vs. 0, U=518 414, P<0.001), postoperative hospital stay (median: 17 days vs. 7 days, U=656 386, P<0.001), and total duration of hospitalization (median: 25 days vs. 12 days, U=648 129, P<0.001), and higher hospitalization costs (median: 71 000 yuan vs. 39 000 yuan, U=557 966, P<0.001). Conclusions:The incidence of SSI after abdominal surgery is 2.9%. In order to reduce the incidence of postoperative SSI, hypoproteinemia should be corrected before surgery, laparoscopic or robotic surgery should be selected when feasible, and the operating time should be minimized. More attentions should be paid and nursing should be strengthened for those patients with hypertension, small bowel surgery and seriously contaminated incision during the perioperative period.
5.Risk factors for surgical site infection after emergency abdominal surgery: a multicenter cross-sectional study in China
Ze LI ; Junru GAO ; Li SONG ; Peige WANG ; Jian'an REN ; Xiuwen WU ; Suming LUO ; Qingjun ZENG ; Yanhong WENG ; Xinjian XU ; Qingzhong YUAN ; Jie ZHAO ; Nansheng LIAO ; Wei MAI ; Feng WANG ; Hui CAO ; Shichen WANG ; Gang HAN ; Daorong WANG ; Hao WANG ; Jun ZHANG ; Hao ZHANG ; Dongming ZHANG ; Weishun LIAO ; Wanwen ZHAO ; Wei LI ; Peng CUI ; Xin CHEN ; Haiyang ZHANG ; Tao YANG ; Lie WANG ; Yongshun GAO ; Jiang LI ; Jianjun WU ; Wei ZHOU ; Zejian LYU ; Jian FANG
Chinese Journal of Gastrointestinal Surgery 2020;23(11):1043-1050
Objective:Surgical site infection (SSI) is the most common infectious complication after emergency abdominal surgery (EAS). To a large extent, most SSI can be prevented, but there are few relevant studies in China. This study mainly investigated the current situation of SSI occurrence after EAS in China, and further explored risk factors for SSI occurrence.Methods:Multi-center cross-sectional study was conducted. Clinical data of patients undergoing EAS in 33 hospitals across China between May 1, 2019 and June 7, 2019 were prospectively collected, including perioperative data and microbial culture results from infected incisions. The primary outcome was the incidence of SSI after EAS, while the secondary outcomes were postoperative hospital stay, ICU occupancy rate, length of ICU stay, hospitalization cost, and mortality within postoperative 30 days. Univariate and multivariate logistic regression models were used to analyze the risk factors of SSI after EAS.Results:A total of 660 EAS patients aged (47.9±18.3) years were enrolled in this study, including 56.5% of males (373/660). Forty-nine (7.4%) patients developed postoperative SSI. The main pathogen of SSI was Escherichia coli [culture positive rate was 32.7% (16/49)]. As compared to patients without SSI, those with SSI were more likely to be older (median 56 years vs. 46 years, U=19 973.5, P<0.001), male [71.4% (35/49) vs. 56.1% (343/611), χ 2=4.334, P=0.037] and diabetes [14.3% (7/49) vs. 5.1% (31/611), χ 2=5.498, P=0.015]; with-lower preoperative hemoglobin (median: 122.0 g/L vs. 143.5 g/L, U=11 471.5, P=0.006) and albumin (median: 35.5 g/L vs. 40.8 g/L, U=9452.0, P<0.001), with higher blood glucose (median: 6.9 mmol/L vs. 6.0 mmol/L, U=17 754.5, P<0.001); with intestinal obstruction [32.7% (16/49) vs. 9.2% (56/611), χ 2=25.749, P<0.001], with ASA score 3-4 [42.9% (21/49) vs. 13.9% (85/611), χ 2=25.563, P<0.001] and with high surgical risk [49.0% (24/49) vs. 7.0% (43/611), χ 2=105.301, P<0.001]. The main operative procedure resulting in SSI was laparotomy [81.6%(40/49) vs. 35.7%(218/611), χ 2=40.232, P<0.001]. Patients with SSI experienced significantly longer operation time (median: 150 minutes vs. 75 minutes, U=25 183.5, P<0.001). In terms of clinical outcome, higher ICU occupancy rate [51.0% (25/49) vs. 19.5% (119/611), χ 2=26.461, P<0.001], more hospitalization costs (median: 44 000 yuan vs. 15 000 yuan, U=24 660.0, P<0.001), longer postoperative hospital stay (median: 10 days vs. 5 days, U=23 100.0, P<0.001) and longer ICU occupancy time (median: 0 days vs. 0 days, U=19 541.5, P<0.001) were found in the SSI group. Multivariate logistic regression analysis showed that the elderly (OR=3.253, 95% CI: 1.178-8.985, P=0.023), colorectal surgery (OR=9.156, 95% CI: 3.655-22.937, P<0.001) and longer operation time (OR=15.912, 95% CI:6.858-36.916, P<0.001) were independent risk factors of SSI, while the laparoscopic surgery (OR=0.288, 95% CI: 0.119-0.694, P=0.006) was an independent protective factor for SSI. Conclusions:For patients undergoing EAS, attention should be paid to middle-aged and elderly patients and those of colorectal surgery. Laparoscopic surgery should be adopted when feasible and the operation time should be minimized, so as to reduce the incidence of SSI and to reduce the burden on patients and medical institutions.
6. Investigation of treatment and analysis of prognostic risk on enterocutaneous fistula in China: a multicenter prospective study
Tao ZHENG ; Haohao XIE ; Xiuwen WU ; Qiang CHI ; Feng WANG ; Zhenhua YANG ; Chaowu CHEN ; Wei MAI ; Suming LUO ; Xiaofei SONG ; Shimin YANG ; Wei ZHOU ; Haiyan LIU ; Xinjian XU ; Zheng ZHOU ; Chuanyuan LIU ; Lian′an DING ; Kai XIE ; Gang HAN ; Hongbin LIU ; Jianzhong WANG ; Shichen WANG ; Peige WANG ; Gefei WANG ; Guosheng GU ; Jian′an REN
Chinese Journal of Gastrointestinal Surgery 2019;22(11):1041-1050
Objective:
To investigate the diagnosis and treatment for enterocutaneous fistula (ECF) in China, and to explore the prognostic factors of ECF.
Methods:
A multi-center cross-sectional study was conducted based on the Registration System of Chinese Gastrointestinal Fistula and Intra-Abdominal Infections to collect the clinical data of ECF patients from 54 medical centers in 22 provinces/municipalities from January 1, 2018 to December 31, 2018. The clinical data included patient gender, age, length of hospital stay, intensive care unit (ICU) admission, underlying diseases, primary diseases, direct causes of ECF, location and type of ECF, complications, treatment and outcomes. All medical records were carefully filled in by the attending physicians, and then re-examined by more than two specialists. The diagnosis of ECF was based on the clinical manifestations, laboratory/imaging findings and intraoperative exploration.
Results:
A total of 1521 patients with ECF were enrolled, including 1099 males and 422 females, with a median age of 55 years. The top three primary diseases of ECF were malignant tumors in 626 cases (41.2%, including 540 gastrointestinal tumors, accounting for 86.3% of malignant tumors), gastrointestinal ulcers and perforations in 202 cases (13.3%), and trauma in 157 cases (10.3%). The direct causes of ECF were mainly surgical operation in 1194 cases (78.5%), followed by trauma in 156 (10.3%), spontaneous fistula due to Crohn
7.Microsurgical repair of ring avulsion injuries
Yuzhou LIU ; Yongjun RUI ; Zhengfeng LU ; Suming WEI ; Lei JIN
Chinese Journal of Microsurgery 2018;41(6):556-558
Objective To investigate the clinical effect of microsurgical repair after ring avulsion injuries. Methods From March, 2009 to December, 2014, 6 cases (6 fingers) of ring avulsion injury were repaired. There were 4 males and 2 females with an age range of 18-30 (mean, 22) years, which were 4 cases of ring finger and 2 cas-es of middle finger. The plane of injury was metacarpophalangeal band. Fracture and dislocation was reduced and fixed if damage fingers following with fracture and dislocation of interphalangeae.The damage ligament and volar plate and extensor tendon was repaired. The digital arteries and veins were repaired, and the digital nerves were sutured. System rehabilitation exercise carried out postoperatively. Results All fingers survived, and were followed-up for 8 to 30 months. The appearance of the fingers was excellent. The avarege range of motion of the proximal interpha-langeal was 80°(ranged from 70°to 100°).The distal interphalangeal was 50°(ranged from 40°to 60°).The sensory re-covery of finger pulp ranged from S3to S3+.The two-point discrimination was 5 mm to 12 mm. According to the Eval-uation Criteria for Finger Replantation and Reconstruction Issued by Chinese Hand Surgery of Chinese Mdical Associ-ation, 4 fingers had excellent while 2 had fairly good function. Conclusion Microsurgical repair of ring avulsion injury can achieve satisfactory clinical results by rehabilitation exercises postoperatively.
8.An 11-site cross-section survey on the prevalence of nutritional risk, malnutrition (undernutrition) and nutrition support among the diagnosis-related group of elderly inpatients younger than 90 years old with coronary heart disease in North and Central China
Jingyong XU ; Yan WANG ; Puxian TANG ; Mingwei ZHU ; Junmin WEI ; Wei CHEN ; Huahong WANG ; Yongdong WU ; Xinying WANG ; Li ZHANG ; Suming ZHOU ; Jianqin SUN ; Birong DONG ; Yanjin CHEN ; Huaihong CHEN ; Huiling LOU
Chinese Journal of Clinical Nutrition 2018;26(3):149-155
Objective To investigate the prevalence of nutritional risk,undernutrition and nutritional support among elderly inpatients with coronary heart disease in 11 tertiary A hospitals in China.Methods Records of elderly patients under the age of 90 with coronary heart disease were collected between March 2012 and May 2012 from 11 tertiary A hospitals in China following the direction of diagnosis related group of Beijing government.Results A total of 1 279 consecutive cases were recruited with the average age 74 years old (65-89).The total nutritional risk prevalence was 28.14% (360/1 279).The prevalence of nutritional risk and nutritional risk score ≥ 5 increased with age.The prevalence of nutritional risk (12.88% vs.30.08% vs.42.28%) and nutritional risk scored ≥5 (10.86% vs.18.61% vs.27.78%)increased with age.Judging from BMI,most patients were overweight or obese (BMI ≥ 24 kg/m2),accounting for 53.0% of the total,and prevalence of nutritional risk in this subgroup was 15.12% (96/635).The prevalence of nutritional risk in patients with normal BMI was 34.24%.The prevalence of undernutrition defined as BMI< 18.5 kg/m2 was 4.25% (51/1 279),among which patients with score ≥ 5 account for 64.7% (33/51).The prevalence of undernutrition defined as nutritional impairment score =3 was 7.58% (97/1 279).In patients with nutritional risk,57 were administrated nutrition support (16.6%);in patients without nutritional risk,21 received nutrition support,mostly parenteral nutrition (16 cases,76.2%).In patients with nutritional risk [(79.46± 7.19) years vs.(76.40± 6.16) years],there were statistically significant difference between those who received nutrition support and those who did not in terms of age and the ratio of patients with nutritional risk scored≥5 (35.1% vs.17.1%) (P =0.001,P=0.002).Conclusions The prevalence of nutritional risk in patients with coronary heart disease was high.The prevalence of undernutrition was low.Prevalence of overweight and obese was high,but there was still nutritional risk in this group of patients.The patients who received nutrition support were older and had high nutritional impairment score,but the indication is not rationale.
9.TLD-based quality audit for radiotherapy dosimetry under reference and non-reference condition in Henan province
Xiaojun CHENG ; Chuanpeng HU ; Hongbing QIAO ; Kunjie WEI ; Suming LUO ; Zhijian HE
Chinese Journal of Radiological Medicine and Protection 2014;34(6):446-450
Objective To verify the reliability of radiotherapy dosimetric parameters in reference and non-reference conditions using thermoluminescent dosimeters (TLDs).Methods Using the established TLD method,the dose variations with different radiation field sizes and 45 ° wedge plate were verified for 10 photon beams of 6 MV,together with dosimetric parameters at the point of maximum axial dose for 4 electron beams of 9 MeV under reference and non-reference conditions.Comparisons were made between TLD results and finger ionization chamber results.Results The average relative deviation,for 6 MV photon beams,between TLD results and finger ionization chamber measurements was 4.7%,within ± 7% as required by the IAEA.The average relative deviation,for 9 MeV electron beam,between TLD results and plane parallel ionization chamber measurements was 2.4 %,not beyond ± 5% permitted by IAEA.Conclusions Using TLD method to verify the radiotherapy dosimetric parameters in reference and non-reference conditions was reliable,simple and feasible.
10.Dosimetric verification for radiotherapy quality audit under reference and non-reference conditions in Jiangsu province
Jin WANG ; Ningle YU ; Chunyong YANG ; Xiang DU ; Wei CHEN ; Suming LUO
Chinese Journal of Radiological Medicine and Protection 2014;34(6):451-455
Objective To verify the methodology for auditing dosimetric parameters in reference and non-reference conditions with thermoluminescent dosimeters (TLDs).Methods Under reference and non-reference conditions,the established TLD methods were used to observe the absorbed dose variations with depth,SSD,field size and 45 wedges for 10 photon beams at 5 hospitals.Dosimetric parameters,including doses at Dmax points in axis,on 5 electron beams of 9 MeV were measured.The measurement results were compared between the TLDs and plane parallel ionization chambers.Results For 6 MV photon beams,the relative deviation of between finger ionization chamber method and TLD chips was in the range of-1.7% to 5.4% under on-axis non-reference conditions,and-6.3% to-0.6% under off-axis non-reference conditions,respectively,all within the range of ≤ ± 7% as required by the IAEA.The relative deviation between plane parallel chamber and TLD method was-2.3% to 3.7%,within ± 5% as required by the IAEA.Conclusions It is convenient and feasible to use TLD method for quality audits of dosimetric parameters in radiotherapy.

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