1.Risk factors for lymph node metastasis after RARP in high-risk prostate cancer patients and construction of a nomogram
Qi CAI ; Ziyan AN ; Zhoujie YE ; Jinpeng SHAO ; Kaipeng BI ; Zheng WANG ; Guanqiu CHEN ; Jie ZHU ; Guangfu CHEN ; Shaoxi NIU ; Baojun WANG ; Xin MA ; Jiangping GAO ; Weijun FU
Chinese Journal of Urology 2025;46(8):593-599
Objective:This study investigated the independent risk factors for lymph node metastasis(LNM)in high-risk prostate cancer(HRPCa)patients undergoing robot-assisted radical prostatectomy(RARP),and constructed a nomogram model based on clinical data to improve the accuracy and clinical practicality of preoperative prediction of LNM.Methods:A retrospective analysis was conducted on the clinical data of 218 HRPCa patients who received RARP treatment at the First Medical Center of the PLA General Hospital from January 2020 to March 2025 as the modeling group. The age of the modeling group was(66.91±6.94)years old. 75 cases(34.40%)had a history of smoking,and 48 cases(22.02%)had a history of drinking. There were a body mass index(BMI)of 25.55(23.58,27.00)kg/m 2,a total prostate-specific antigen(tPSA)of 20.59(10.42,30.61)ng/ml,a free prostate-specific antigen(fPSA)of 1.87(1.04,3.26)ng/ml,a prostate volume(PV)of(41.19±21.00)ml,a prostate-specific antigen density(PSAD)of 0.52(0.30,0.84)ng/ml 2. Among the patients,60 cases(27.52%)had a preoperative biopsy Gleason score >8,and the percentage of positive biopsy cores(PPBC)was 50%(31%,80%). Thirty-one patients(14.22%)were staged clinically as >T 2c. The diagnostic criteria for high-risk prostate cancer(HRPCa)were defined as meeting any one of the following:PSA >20 ng/ml,Gleason score on prostate biopsy ≥8,or clinical stage ≥T 3. Among the 218 patients in the modeling cohort,67 cases(30.73%)met two of the criteria,and 7 cases(3.21%)met all three criteria. All 218 patients underwent RARP,and based on postoperative pathology,they were divided into the LNM group and the non-LNM group. The relationship between the number of diagnostic criteria met and the occurrence of LNM was analyzed. An external validation cohort included 42 HRPCa patients who underwent RARP at the Third,Fifth Medical Centers of the PLA General Hospital between January 2023 and May 2025. Their mean age was(66.79±5.92)years. Eighteen patients(42.86%)had a smoking history,and nine(21.43%)had a history of alcohol consumption. The median BMI was 26.00(23.80,27.13)kg/m 2. The median tPSA level was 17.34(8.97,27.30)ng/ml. The median fPSA was 1.51(0.83,2.52)ng/ml,and the median PV was(35.57 ± 15.25)ml. The median PSAD was 0.57(0.23,0.87)ng/ml 2,and the median PPBC was 58%(36%,71%). Three patients(7.14%)had a clinical stage >T 2c,and 12 patients(28.57%)had a Gleason score >8 on preoperative biopsy. Univariate and multivariate binary logistic regression analyses were used to identify independent risk factors for LNM,and a nomogram model was constructed based on these factors. The predictive performance of the model was evaluated using receiver operating characteristic(ROC)curves and calibration plots,and the model was validated in the external cohort. Result:According to postoperative pathology,45 patients were classified into the LNM group,and 173 into the non-LNM group. The probability of LNM increased proportionally with the number of diagnostic criteria met for HRPCa(meeting two criteria: OR = 4.762,95% CI 2.323-9.761, P < 0.01;meeting three criteria: OR = 10.667,95% CI 2.187-52.025, P=0.003). Binary logistic regression analysis revealed that age( OR=0.913,95% CI 0.859-0.971, P = 0.004),tPSA( OR=1.039,95% CI 1.018-1.061, P<0.01),PPBC( OR = 5.656,95% CI 1.101-29.056, P = 0.038),and clinical T stage(T 2c stage: OR=2.945,95% CI 0.888-9.769, P=0.077;>T 2c stage OR = 18.351,95% CI 4.790-70.306, P < 0.01)were independent risk factors for postoperative LNM in HRPCa patients after RARP. The ROC curve of the nomogram model based on these factors showed an area under the curve(AUC)of 0.853(95% CI 0.790-0.917). In the external validation cohort,the nomogram achieved an AUC of 0.743(95% CI 0.556-0.929). The calibration plots demonstrated good agreement between the predicted probabilities and actual observations. Conclusions:Age,tPSA,PPBC,and clinical T stage were independent predictors of postoperative LNM in HRPCa patients undergoing RARP. The greater the number of HRPCa diagnostic criteria met,the higher the likelihood of postoperative LNM. The nomogram developed in this study could effectively predict the risk of LNM in HRPCa patients after RARP.
2.The value of ultrasonography in the diagnosis of congenital laryngeal web
Jiangping LI ; Teng MA ; Limei WANG
Chinese Archives of Otolaryngology-Head and Neck Surgery 2025;32(6):386-389,393
OBJECTIVE To explore the value of ultrasonography in the diagnosis of congenital laryngeal web.METHODS A total of 10 pediatric patients with congenital laryngeal web who were admitted to Beijing Tongren Hospital,Capital Medical University from April 2013 to December 2024 were collected.Among them,there were 5 males and 5 females,with ages ranging from 1 month and 16 days to 16 years old after birth,and a median age of 1 year and 11 months.Clinical manifestations included laryngeal stridor,hoarseness,or weak crying after birth.All patients underwent laryngoscopy and laryngeal ultrasonography.The diagnosis was made by combining ultrasound and laryngoscopy examinations.RESULTS It was confirmed by laryngoscopy and operation:The final diagnosis was glottic laryngeal web in 7 cases and combined glottic-subglottic type in 3 cases.In the transverse ultrasound view,glottic laryngeal web appears as a triangular hypoechoic area at the anterior commissure of the glottis level,with its posterior edge presenting as an arc shape,and the interface with air is hyperechoic.In the sagittal ultrasound view,certain web-like structures appear as a strip of hypoechoic area in the midline behind the thyroid cartilage.The thickness can be measured to determine whether it extends from the glottis to the subglottis.For infans,and for subglottic laryngeal web,it is difficult to show the lesion by ultrasound.CONCLUSION Ultrasonography is helpful in the diagnosis of laryngeal web and can display the thickness of the web in the sagittal plane,providing three-dimensional information for preoperative planning.
3.Exploration of the medication pattern of traditional Chinese medicine for exogenous cough based on R language data mining
Jiale MA ; Qiong CAI ; Mingrui WEI ; Jia WU ; Min PI ; Zekun YANG ; Lanting YANG ; Jiangping XIAO ; Shuqiong ZHANG ; Xilong PAN
Chinese Journal of Pharmacoepidemiology 2025;34(10):1147-1158
Objective To collect and analyze outpatient prescription data for exogenous cough treatment from a hospital in Shenzhen,and to identify the characteristics and medication patterns of traditional Chinese medicine(TCM).Methods This study collected prescriptions from a hospital in Shenzhen for exogenous cough treatment in January 2024.R language for data mining were used to analyze the medication frequency,clustering patterns,and association rules in the treatment of exogenous cough by TCM and to explore the medication patterns and the usage of classic formulas in TCM for this condition.Results A total of 451 outpatient prescriptions for exogenous cough were include,the top ten most frequently used herbs were Licorice,Bitter almond,Bellflower,Ephedra,Tangerine peel,Stemonae radix,Tuckahoe,Pinellia ternata,Nepeta,Bulb of thunberg fritillary.Cluster analysis and association rules revealed that San'ao decoction,Kikyodon soup,and Zhisou powder were commonly prescribed,targeting lung function,dispersing wind,and resolving phlegm to effectively alleviate cough symptoms.Significant differences in medication usage were observed across different syndrome types.For the wind cold attacking lung pattern,the core herbs were warm in nature and focused on dispersing with acrid-warm properties.Conversely,the treatment of wind heat attacking the lung pattern typically involved cold-natured herbs,with a primary focus on clearing and draining lung heat.Stratification by age revealed that the pediatric group often used drugs with mild properties,such as Stemona and Shegan.The young adult group tended to be prescribed cold-natured drugs like Forsythia and Hogfonnel Root.The middle-aged and elderly group preferred warming and tonifying drugs such as Japanese Catnip and Perilla frutescens.Conclusion The TCM treatment of exogenous cough primarily focuses on releasing the exterior and dispersing the lung.Due to the region's subtropical monsoon climate and temperature fluctuations physicians flexibly modified classical formulas such as San'ao decoction and Zhisou powder according to individual constitutions and symptom patterns.This targeted,syndrome-based approach effectively disperses the lung qi,stops cough and transforms phlegm,and alleviates cough.
4.Risk factors for lymph node metastasis after RARP in high-risk prostate cancer patients and construction of a nomogram
Qi CAI ; Ziyan AN ; Zhoujie YE ; Jinpeng SHAO ; Kaipeng BI ; Zheng WANG ; Guanqiu CHEN ; Jie ZHU ; Guangfu CHEN ; Shaoxi NIU ; Baojun WANG ; Xin MA ; Jiangping GAO ; Weijun FU
Chinese Journal of Urology 2025;46(8):593-599
Objective:This study investigated the independent risk factors for lymph node metastasis(LNM)in high-risk prostate cancer(HRPCa)patients undergoing robot-assisted radical prostatectomy(RARP),and constructed a nomogram model based on clinical data to improve the accuracy and clinical practicality of preoperative prediction of LNM.Methods:A retrospective analysis was conducted on the clinical data of 218 HRPCa patients who received RARP treatment at the First Medical Center of the PLA General Hospital from January 2020 to March 2025 as the modeling group. The age of the modeling group was(66.91±6.94)years old. 75 cases(34.40%)had a history of smoking,and 48 cases(22.02%)had a history of drinking. There were a body mass index(BMI)of 25.55(23.58,27.00)kg/m 2,a total prostate-specific antigen(tPSA)of 20.59(10.42,30.61)ng/ml,a free prostate-specific antigen(fPSA)of 1.87(1.04,3.26)ng/ml,a prostate volume(PV)of(41.19±21.00)ml,a prostate-specific antigen density(PSAD)of 0.52(0.30,0.84)ng/ml 2. Among the patients,60 cases(27.52%)had a preoperative biopsy Gleason score >8,and the percentage of positive biopsy cores(PPBC)was 50%(31%,80%). Thirty-one patients(14.22%)were staged clinically as >T 2c. The diagnostic criteria for high-risk prostate cancer(HRPCa)were defined as meeting any one of the following:PSA >20 ng/ml,Gleason score on prostate biopsy ≥8,or clinical stage ≥T 3. Among the 218 patients in the modeling cohort,67 cases(30.73%)met two of the criteria,and 7 cases(3.21%)met all three criteria. All 218 patients underwent RARP,and based on postoperative pathology,they were divided into the LNM group and the non-LNM group. The relationship between the number of diagnostic criteria met and the occurrence of LNM was analyzed. An external validation cohort included 42 HRPCa patients who underwent RARP at the Third,Fifth Medical Centers of the PLA General Hospital between January 2023 and May 2025. Their mean age was(66.79±5.92)years. Eighteen patients(42.86%)had a smoking history,and nine(21.43%)had a history of alcohol consumption. The median BMI was 26.00(23.80,27.13)kg/m 2. The median tPSA level was 17.34(8.97,27.30)ng/ml. The median fPSA was 1.51(0.83,2.52)ng/ml,and the median PV was(35.57 ± 15.25)ml. The median PSAD was 0.57(0.23,0.87)ng/ml 2,and the median PPBC was 58%(36%,71%). Three patients(7.14%)had a clinical stage >T 2c,and 12 patients(28.57%)had a Gleason score >8 on preoperative biopsy. Univariate and multivariate binary logistic regression analyses were used to identify independent risk factors for LNM,and a nomogram model was constructed based on these factors. The predictive performance of the model was evaluated using receiver operating characteristic(ROC)curves and calibration plots,and the model was validated in the external cohort. Result:According to postoperative pathology,45 patients were classified into the LNM group,and 173 into the non-LNM group. The probability of LNM increased proportionally with the number of diagnostic criteria met for HRPCa(meeting two criteria: OR = 4.762,95% CI 2.323-9.761, P < 0.01;meeting three criteria: OR = 10.667,95% CI 2.187-52.025, P=0.003). Binary logistic regression analysis revealed that age( OR=0.913,95% CI 0.859-0.971, P = 0.004),tPSA( OR=1.039,95% CI 1.018-1.061, P<0.01),PPBC( OR = 5.656,95% CI 1.101-29.056, P = 0.038),and clinical T stage(T 2c stage: OR=2.945,95% CI 0.888-9.769, P=0.077;>T 2c stage OR = 18.351,95% CI 4.790-70.306, P < 0.01)were independent risk factors for postoperative LNM in HRPCa patients after RARP. The ROC curve of the nomogram model based on these factors showed an area under the curve(AUC)of 0.853(95% CI 0.790-0.917). In the external validation cohort,the nomogram achieved an AUC of 0.743(95% CI 0.556-0.929). The calibration plots demonstrated good agreement between the predicted probabilities and actual observations. Conclusions:Age,tPSA,PPBC,and clinical T stage were independent predictors of postoperative LNM in HRPCa patients undergoing RARP. The greater the number of HRPCa diagnostic criteria met,the higher the likelihood of postoperative LNM. The nomogram developed in this study could effectively predict the risk of LNM in HRPCa patients after RARP.
5.Exploration of the medication pattern of traditional Chinese medicine for exogenous cough based on R language data mining
Jiale MA ; Qiong CAI ; Mingrui WEI ; Jia WU ; Min PI ; Zekun YANG ; Lanting YANG ; Jiangping XIAO ; Shuqiong ZHANG ; Xilong PAN
Chinese Journal of Pharmacoepidemiology 2025;34(10):1147-1158
Objective To collect and analyze outpatient prescription data for exogenous cough treatment from a hospital in Shenzhen,and to identify the characteristics and medication patterns of traditional Chinese medicine(TCM).Methods This study collected prescriptions from a hospital in Shenzhen for exogenous cough treatment in January 2024.R language for data mining were used to analyze the medication frequency,clustering patterns,and association rules in the treatment of exogenous cough by TCM and to explore the medication patterns and the usage of classic formulas in TCM for this condition.Results A total of 451 outpatient prescriptions for exogenous cough were include,the top ten most frequently used herbs were Licorice,Bitter almond,Bellflower,Ephedra,Tangerine peel,Stemonae radix,Tuckahoe,Pinellia ternata,Nepeta,Bulb of thunberg fritillary.Cluster analysis and association rules revealed that San'ao decoction,Kikyodon soup,and Zhisou powder were commonly prescribed,targeting lung function,dispersing wind,and resolving phlegm to effectively alleviate cough symptoms.Significant differences in medication usage were observed across different syndrome types.For the wind cold attacking lung pattern,the core herbs were warm in nature and focused on dispersing with acrid-warm properties.Conversely,the treatment of wind heat attacking the lung pattern typically involved cold-natured herbs,with a primary focus on clearing and draining lung heat.Stratification by age revealed that the pediatric group often used drugs with mild properties,such as Stemona and Shegan.The young adult group tended to be prescribed cold-natured drugs like Forsythia and Hogfonnel Root.The middle-aged and elderly group preferred warming and tonifying drugs such as Japanese Catnip and Perilla frutescens.Conclusion The TCM treatment of exogenous cough primarily focuses on releasing the exterior and dispersing the lung.Due to the region's subtropical monsoon climate and temperature fluctuations physicians flexibly modified classical formulas such as San'ao decoction and Zhisou powder according to individual constitutions and symptom patterns.This targeted,syndrome-based approach effectively disperses the lung qi,stops cough and transforms phlegm,and alleviates cough.
6.Application of cognitive-motor dual-task training in stroke:a bibliometrics analysis
Lu ZHANG ; Jiangping MA ; Erli YANG ; Qiuhua CHEN ; Lijun DONG ; Xiaobing YIN
Chinese Journal of Rehabilitation Theory and Practice 2024;30(9):1034-1042
Objective To analyze the current status and frontier trends of research on the application of cognitive-motor dual task training(CMDT)in stroke. Methods Relevant literatures on the application of CMDT in stroke were retrieved from CNKI,Wanfang data,VIP,SinoMed and Web of Science Core Collection from inception to October 11,2023,and was analyzed with CiteSpace 6.2R4. Results A total of 285 articles were included with 124 in Chinese and 161 in English.The annual number of publications showed a general upward trend.United States,Canada,Netherlands,China and United Kingdom were the lead-ing countries in terms of output in English.The scholar with the most publications in Chinese was Zheng Jiejiao,and the Department of Rehabilitation Medicine in Huadong Hospital of Fudan University was the leading institu-tion for Chinese publications.Vrije University Amsterdam was the leading institution for English publications.The most frequent Chinese keywords were gait,falls,balance,cognition and postural control.The most frequent English keywords were dual-task,walking,gait,balance and cognitive-motor interference.Bursting keywords from the past two years included gait training,cognitive tasks,balance ability and cognitive-motor interference. Conclusion The researches on the application of CMDT in stroke are on the rise,with hotspots including gait training,cognitive tasks and cognitive-motor interference.The mechanisms of CMDT and the development of optimal CMDT rehabilitation protocols for stroke may be researched more in the future.
7.Relationship between bone cement-vertebral volume ratio and therapeutic effect of osteoporotic vertebral compression fractures
Chao MA ; Jiangping DING ; Bin WANG ; Ben NIU ; Wumaier MUHETAER ; Guozhu TANG ; Hongtao YANG ; Xinwen FENG
Chinese Journal of Tissue Engineering Research 2024;28(29):4652-4656
BACKGROUND:Percutaneous vertebroplasty has become the main treatment method for osteoporotic vertebral compression fractures due to its advantages of convenient operation and low trauma.However,the optimal bone cement-vertebral volume ratio has not been determined. OBJECTIVE:To investigate the effect of bone cement-vertebral volume ratio on percutaneous vertebroplasty for osteoporotic vertebral compression fractures. METHODS:The clinical data of 100 patients with single-stage osteoporotic vertebral compression fractures admitted to Xinjiang Bazhou People's Hospital from July 2019 to July 2022 were retrospectively analyzed.All patients received percutaneous vertebroplasty.According to the bone cement-vertebral volume ratio,they were divided into the low volume group(15%≤ratio≤20%)and the high volume group(20%
8.Comparison of three fixed-field IMRT plans for nasal cavity and paranasal sinus tumors
Jiming YANG ; Ting LU ; Min MA ; Yong WU ; Yingying ZHOU ; Jiangping REN ; Xun WANG ; Jianxin GUO
Chinese Journal of Radiological Medicine and Protection 2022;42(12):950-957
Objective:To compare three fixed-field intensity-modulated radiotherapy (IMRT) plans for nasal cavity and paranasal sinus tumors, including the coplanar IMRT (C-IMRT) plan and the non-coplanar IMRT(NC-IMRT) plan which were based on a conventional C-arm LINAC (Trilogy), and the coplanar IMRT (H-IMRT) plan based on an O-ring LINAC (Halcyon).Methods:Based on the data of 10 patients in the Ningbo First Hospital from December 2018 to December 2021 with nasal cavity and paranasal sinus tumors who underwent postoperative radiotherapy, this study redesigned three IMRT plans with the same prescribed doses and optimization objectives. Then, this study compared the doses of target volumes and organ at risks(OARs), the validation pass rates, and the execution time of these plans. Friedman test was employed in this study, and multiple comparisons were further made in cases of different results.Results:The differences in the conformal index (CI) of PTV and PTV boost of the three plans were statistically significant ( χ2 = 7.51, 9.69, P < 0.05). The multiple comparisons showed that the median CI of the H-IMRT plan was higher than that of the NC-IMRT plan ( Z = 2.53, 2.68, P < 0.05). The differences in other parameters of target volumes were not statistically significant. Compared with the C-IMRT plan, the H-IMRT plan reduced the Dmax of bilateral lenses, bilateral corneas, ipsilateral optic nerve, and ipsilateral eyeball ( Z = 2.80, 2.80, 2.80, 2.80, 2.81, 2.09, P < 0.05). Compared with the C-IMRT plan, the NC-IMRT reduced the Dmax of bilateral lenses, corneas, and eyeballs and contralateral optic nerve ( Z = 2.80, 2.66, 2.80, 2.70, 2.29, 2.29, 2.65, P < 0.05) and reduced the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, P < 0.05). Compared with the NC-IMRT plan, the H-IMRT plan reduced the Dmax of the ipsilateral lens and cornea ( Z = 2.50, 2.08, P < 0.05), but increased the Dmax of the contralateral optic nerve and the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, 2.80, P < 0.05). The validation pass rate of the three plans met the institutional standards, and the differences were not statistically significant. Moreover, the H-IMRT plan had the shortest median execution time (172.00 s), followed by the C-IMRT plan (337.50 s), and the NC-IMRT plan (388.00 s). Conclusions:The verification pass rate of the three plans can achieve the requirements of treatment implementation. The three plans had similar dosimetric differences in target volumes. However, the H-IMRT and NC-IMRT plans can protect the normal tissues (especially optical organs) more effectively than the C-IMRT plan, which is conducive to reducing the toxicity after radiotherapy and provides space for local dose increase or the radiotherapy for the treatment of tumor recurrence. The execution efficiency of the three plans is in the order of H-IMRT > C-IMRT > NC-IMRT. It is necessary to select appropriate radiotherapy equipment and technology according to actual situations.
9.Dosimetric comparison between conventional IMRT and EBCRT combined with IMRT for post-mastectomy left-sided breast cancer patients
Jiming YANG ; Hang CHENG ; Min MA ; Weichao ZHANG ; Yong WU ; Jiangping REN ; Jianxin GUO
Chinese Journal of Radiological Medicine and Protection 2022;42(4):262-268
Objective:To investigate the dosimetric differences between conventional IMRT and electron beam conformal radiotherapy (EBCRT) combined with IMRT for post-mastectomy left-sided breast cancer patients.Methods:A total of 20 post-mastectomy left-sided breast cancer patients who were treated in the Ningbo First Hospital from June 2018 to October 2021 were retrospectively studied. The planning target volume (PTV) included the supra-and infra-clavicular regions(PTV sc)and the ipsilateral chest wall (PTV cw), and the prescribed dose was 50 Gy/25 f. All radiotherapy plans were designed using the Varian Eclipse treatment planning system (TPS). After that, the dose distribution of the target volume and the dose exposure of organs at risk (OARs) were compared and analyzed. Results:All the IMRT plans met the clinical requirements, yet 2/20 of the EBCRT combined with IMRT plans were not clinically accepted. For these two patients, the maximum chest wall thickness was 3.7 cm and 4.4 cm each, and the designed electron beam energy was 12 MeV and 15 MeV, respectively. The dose to the ipsilateral lung of these two patients exceeded the institution-specific dose limit standard. For the remaining 18 patients whose chest wall thickness was 3 cm or less, the designed electron beams were 9 MeV or less. All the EBCRT combined with IMRT plans were clinically accepted. The target dose distribution of the conventional IMRT was better than that of the EBCRT combined with IMRT (uniformity index (HI): PTV sc: t = -10.20, P<0.05; PTV cw: t = -9.24, P<0.05; conformal index (CI): PTV all: t = 10.39, P <0.05). For OARs, the V5 Gy, V20 Gy, and Dmean of the ipsilateral lung of EBCRT combined with IMRT were lower than those of IMRT ( t = 5.98, 6.30, 11.30, P <0.05). Specifically, the V25 Gy and Dmean of heart decreased by 8.3% and 4.79 Gy, respectively ( t = 15.23, 15.76, P<0.05), the Dmean of the left anterior descending coronary artery (LADCA) decreased by 44.03% ( t = 11.69, P <0.05), and the V5 Gy and Dmean of the contralateral breast decreased by 7.9% and 0.8 Gy, respectively ( t = 3.66, 4.93, P<0.05). The dosimetric differences of other OARs were not statistically significant ( P > 0.05). Conclusions:For post-mastectomy left-sided breast cancer patients with a chest wall thickness of less than 3 cm, EBCRT combined IMRT can significantly reduce the exposure dose to the heart, the ipsilateral lung, and the contralateral breast, which is beneficial to reducing the potential risk of long-term complications after radiotherapy and can further improve the long-term overall survival rate of patients. For patients with thick chest wall, IMRT plans are more technologically ideal.
10.Tolerance and dosimetric study of multi-leaf collimator leaf position accuracy for dynamic intensity-modulated radiotherapy
Jiming YANG ; Min MA ; Yong WU ; Jiangping REN
Chinese Journal of Radiation Oncology 2021;30(11):1167-1172
Objective:To evaluate the dosimetric effect of multi-leaf collimator (MLC) position error on dynamic intensity-modulated radiotherapy (dMLC-IMRT), aiming to provide guidance for the establishment of MLC quality control accuracy and operation tolerance.Methods:In the phantom study, the virtual water phantom established in the treatment planning system (TPS), and three dynamic sliding window test fields with gap width of 5 mm, 10 mm and 20 mm were designed. Clinical treatment plans of 7 common tumor types were extracted, including nasopharyngeal carcinoma, glioma, lung cancer, esophageal cancer, cervical cancer, prostate cancer, and breast cancer, with 6 cases in each. MLC errors were introduced into the copy from original plan to generate the simulation plans. MLC errors included systematic open/close error, systematic deviation error and random error. The dosimetric differences between the original and simulation plans were compared.Results:The phantom study showed that the symbol of dose deviation was the same as that of systematic open/close error, and the value was increased with the increase of MLC error and decreased with the increase of gap width. The results of patient study showed that the systematic open/close error had a significant effect on dosimetry, the target volume dose sensitivities of different plans were 7.258-13.743%/mm, and were negatively correlated with the average field width. The dosimetric deviation caused by the systematic shift error below 2 mm was less than 2%. The dosimetric change caused by the random error below 2 mm could be neglected in clinical treatment.Conclusions:The minimal gap width should be limited in TPS, whereas the quality control of MLC should be strengthened. In addition, for the dynamic intensity-modulated treatment technology, 2 mm random error was suggested to be the operation tolerance during treatment delivery, and 0.2 mm alignment accuracy on each side (or 0.4 mm unilateral) is recommended to be the MLC quality control accuracy to ensure the dose accuracy of radiotherapy for different tumors.

Result Analysis
Print
Save
E-mail