1.Primary observational study of tocilizumab in children with severe acute necrotizing encephalopathy
Yiping ZHOU ; Weiming CHEN ; Xiaodong ZHU ; Qin JIANG ; Yun CUI ; Chunxia WANG ; Yuqian REN ; Guoping LU ; Yucai ZHANG
Chinese Journal of Pediatrics 2024;62(8):764-769
		                        		
		                        			
		                        			Objective:To investigate the efficacy and safety of tocilizumab in the treatment of critically ill children with acute necrotizing encephalopathy (ANE).Methods:It is a retrospective cohort study. The children with ANE admitted to the pediatric intensive care unit of 4 Chinese tertiary hospitals from December 2022 to November 2023 were divided into conventional treatment group and tocilizumab group, and the comparison between groups was performed by using Mann ‐ Whitney U test or Chi-square test. Results:Among 21 cases of severe ANE, there were 11 males with the onset age of 65 (27, 113) months. The duration from onset to PICU admission was 2 (1, 2) days. There were 13 cases of ultra-high fever (greater than 40 ℃), including 18 cases of convulsions, and 19 cases with a GCS score of less than 8 points. The causative agent was novel coronavirus Omicron in 7 cases and influenza A in 14 cases. All cases had central respiratory failure requiring mechanical ventilation. Of the 21 cases, 18 were shock, 15 were coagulopathy, 10 were kidney injury and 13 were liver dysfunction. Of these hospitalized patients, 8 children with ANE were treated with tocilizumab. Eight cases received continuous blood purification (CBP) treatment, 5 of them were combined with plasmapheresis. Serum cytokine levels were elevated in 21 children with ANE, including (interleukin, IL)-6 and IL-8 (61 (22, 1 513) and 68 (5, 296) ng/L). There were 14 cases (67%) deaths, including 11 cases in the conventional treatment group and 3 cases in the tocilizumab group. There was no significant difference in the mortality rate between the two groups ( P=0.056). Tocilizumab-related rash or other adverse events were not observed. Conclusions:The motality of critically ill ANE patients was high. The combination of Tocilizumab with conventional treatment did not reduce the motality of severe ANE patients, and no adverse reactions of tocilizumab were observed.
		                        		
		                        		
		                        		
		                        	
2.Comparison of clinical characteristics and outcomes of infants with moderate and severe acute respiratory distress syndrome diagnosed according to baseline oxygenation index
Boliang FANG ; Kechun LI ; Feng XU ; Guoping LU ; Xiaoxu REN ; Yucai ZHANG ; Youpeng JIN ; Ying WANG ; Chunfeng LIU ; Yibing CHENG ; Qiaozhi YANG ; Shufang XIAO ; Yiyu YANG ; Ximin HUO ; Zhixian LEI ; Hongxing DANG ; Shuang LIU ; Zhiyuan WU ; Jiansheng ZENG ; Suyun QIAN
Chinese Pediatric Emergency Medicine 2023;30(8):561-565
		                        		
		                        			
		                        			Objective:To analyze the difference of clinical characteristics and outcomes of infants with moderate and severe pediatric acute respiratory distress syndrome(PARDS)diagnosed according to baseline oxygenation index(OI) in pediatric intensive care unit(PICU).Methods:Second analysis of the data collected from the "Efficacy of pulmonary surfactant (PS) in the treatment of children with moderate and severe ARDS" program.Retrospectively compare of the differences in clinical data such as general condition, underlying diseases, OI, mechanical ventilation, PS administration and outcomes among infants with moderate and severe PARDS divided by baseline OI who admitted to PICUs at 14 participating tertiary hospitals from 2016 to December 2021.Results:Among the 101 cases, 55 cases (54.5%) were moderate and 46 cases (45.5%) were severe PARDS.The proportion of male in the severe group (50.0% vs.72.7%, P=0.019) and the pediatric critical illness score(PCIS)[72 (68, 78) vs.76 (70, 80), P=0.019] were significantly lower than those in the moderate group, while there was no significant difference regarding age, body weight, etiology of PARDS and underlying diseases.The utilization rate of high-frequency ventilator in the severe group was significantly higher than that in the moderate group (34.8% vs.10.9%, P=0.004), but there was no significant difference in PS use, fluid load and pulmonary complications.The 24 h OI improvement (0.26±0.33 vs.0.04±0.34, P=0.001) and the 72 h OI improvement[0.34 (-0.04, 0.62) vs.0.15 (-0.14, 0.42), P=0.029)]in the severe group were significantly better than those in the moderate group, but there was no significant difference regarding mortality, length of hospital stay and intubation duration after diagnosis of PARDS between the two groups. Conclusion:In moderate and severe(divided by baseline OI) PARDS infants with invasive mechanical ventilation, children in severe group have better oxygenation improvement in the early stage after PARDS identified and are more likely to receive high frequency ventilation compared to those in moderate group.Baseline OI can not sensitively distinguish the outcomes and is not an ideal index for PARDS grading of this kind of patient.
		                        		
		                        		
		                        		
		                        	
3.A comparative study of the effects of citrate and heparin anticoagulation on coagulation function and efficacy in children with septic shock undergoing continuous blood purification
Xiaoming ZHONG ; Shasha LUO ; Ruihua REN ; Jie LAI ; Guoping DENG ; Huifang ZHU
Chinese Critical Care Medicine 2023;35(8):856-859
		                        		
		                        			
		                        			Objective:To compare the effects of citrate and heparin anticoagulation on coagulation function and efficacy in children with septic shock undergoing continuous blood purification (CBP), and to provide guidance for CBP anticoagulation in children with septic shock.Methods:A case control study was conducted. Thirty-seven children with septic shock admitted to the pediatric intensive care unit (PICU) of the First Affiliated Hospital of Gannan Medical University from July 2019 to September 2022 were enrolled as the research subjects. The patients were divided into citrate local anticoagulation group and heparin systemic anticoagulation group according to different anticoagulation methods. The baseline data, the level of coagulation indicators [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fib), D-dimer] before treatment and 1 day after weaning from CBP, serum inflammatory mediators [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), hypersensitivity C-reactive protein (hs-CRP), procalcitonin (PCT)], bleeding complications during CBP and 7-day mortality were collected.Results:A total of 37 cases were enrolled finally, including 17 cases with citric acid local anticoagulation and 20 cases with heparin systemic anticoagulation. There was no statistically significant difference in general data such as gender, age, and body weight of children between the two groups. There were no statistically significant differences in baseline levels of coagulation indicators and inflammatory mediators before treatment of children between the two groups. One day after weaning from CBP, both groups showed varying degrees of improvement in coagulation indicators compared with those before treatment. Compared with before treatment, the PT of the heparin systemic anticoagulation group was significantly shortened after 1 day of weaning (s: 11.82±2.05 vs. 13.64±2.54), APTT and TT were significantly prolonged [APTT (s): 51.54±12.69 vs. 35.53±10.79, TT (s): 21.95±4.74 vs. 19.30±3.33], D-dimer level was significantly reduced (mg/L: 1.92±1.58 vs. 4.94±3.94), with statistically significant differences (all P < 0.05). While in the citrate local anticoagulation group, only APTT was significantly prolonged after treatment compared with that before treatment (s: 49.28±10.32 vs. 34.34±10.32, P < 0.05). There were no statistically significant differences in other coagulation indicators compared with before treatment. Compared with the citric acid local anticoagulation group, the PT of the heparin systemic anticoagulation group was significantly shortened after treatment (s: 11.82±2.05 vs. 13.61±3.05, P < 0.05), and the D-dimer level was significantly reduced (mg/L: 1.92±1.58 vs. 3.77±2.38, P < 0.01). The levels of inflammatory mediators in both groups were significantly reduced 1 day after CBP weaning compared with those before treatment [citric acid local anticoagulation group: hs-CRP (mg/L) was 12.53±5.44 vs. 22.65±7.27, PCT (μg/L) was 1.86±1.20 vs. 3.30±2.34, IL-6 (ng/L) was 148.48±34.83 vs. 202.32±48.62, TNF-α (ng/L) was 21.38±7.71 vs. 55.14±15.07; heparin systemic anticoagulation group: hs-CRP (mg/L) was 11.82±4.93 vs. 21.62±8.35, PCT (μg/L) was 1.90±1.08 vs. 3.18±1.97, IL-6 (ng/L) was 143.81±33.41 vs. 194.02±46.89, TNF-α (ng/L) was 22.44±8.17 vs. 56.17±16.92, all P < 0.05]. However, there was no statistically significant difference between the two groups (all P > 0.05). There was no statistically significant difference in bleeding complication during CBP and 7-day mortality in children between the citrate local anticoagulation group and the heparin systemic anticoagulation group (5.9% vs. 30.0%, 17.6% vs. 20.0%, both P > 0.05). Conclusions:Heparin for systemic anticoagulation and regional citrate anticoagulation can significantly reduce the levels of IL-6, TNF-α, hs-CRP and PCT in children with septic shock, and relieve inflammatory storm. Compared with citric acid local anticoagulation, heparin systemic anticoagulation can shorten the PT and reduce the level of D-dimer in children with septic shock, which may benefit in the prevention and treatment of disseminated intravascular coagulation (DIC).
		                        		
		                        		
		                        		
		                        	
4.Construction and analysis of a predictive model for chemotherapy response of patients with colorectal cancer based on tissue chip technology
Linghua CONG ; Guoping ZHONG ; Zuguo YUAN ; Ying REN ; Gun CHEN ; Laifu FANG ; Ping LI
Chinese Journal of Endocrine Surgery 2023;17(3):307-311
		                        		
		                        			
		                        			Objective:To explore the prediction model of tissue chip technology for the chemotherapy response of patients with colorectal cancer.Methods:217 patients with colorectal cancer who had received standardized chemotherapy in the Affiliated People’s Hospital of Ningbo University from Jan. 2017 to Dec. 2019 were prospectively selected. The patients were randomly divided into training set (152 cases) and test set (65 cases) according to the ratio of 7:3, and were followed up for 6 months. The clinical data of the patients in the training set were compared, the expression levels of Ang-2, caspase-3 and CD147 in the patients were analyzed by tissue microarray technology, and the related factors affecting the responsiveness of colorectal cancer chemotherapy were analyzed by the Logistic regression model. R software was used based on the training set. A nomogram prediction model was built and model performance on the test set was evaluated.Results:One case was excluded from the training center, and 151 cases were finally included, including 93 cases in the chemotherapy response group and 58 cases in the chemotherapy response group. The tumor diameter, serum carcinoembryonic antigen, caspase3, Ang2 expression level, and the proportion of clinical stage IV in the poor chemotherapy group were significantly higher than those in the good chemotherapy group (all P<0.05) ; Logistic regression showed tumor diameter ( OR=2.394), serum carcinoembryonic antigen ( OR=1.878), caspase-3 ( OR=4.261), Ang-2 expression level ( OR=5.457), and clinical stage IV ( OR=5.954) were independent risk factors for adverse drug reactions in patients with colorectal cancer (all P<0.05). The consistency index (C-index) for predicting the factors related to adverse chemotherapy reactions in patients with colorectal cancer was 0.915. External verification showed that the sensitivity was 86.96%, the specificity was 92.50%, and the accuracy was 90.48% (42/65) . Conclusion:The expression levels of Ang-2 and caspase-3 are correlated with the responsiveness of colorectal cancer to chemotherapy, and can be used as predictive indicators to evaluate the responsiveness of colorectal cancer to chemotherapy.
		                        		
		                        		
		                        		
		                        	
5.A review of patients with dysphagia after anterior cervical discectomy and fusion
Ying REN ; Qunfei YU ; Guoping XU ; Yaojing MA ; Shengjun QIAN ; Hua ZHANG
Chinese Journal of Practical Nursing 2023;39(1):65-71
		                        		
		                        			
		                        			Anterior cervical discectomy and fusion is one of the classic procedures for the treatment of cervical spondylosis, and dysphagia is a common perioperative complication of this procedure, which affects patients′ recovery to different degrees. This paper summarizes and analyzes the perioperative assessment and interventions in the care of patients with dysphagia after anterior cervical discectomy and fusion, aiming to improve clinical nursing staff′s attention to dysphagia in patients after anterior cervical discectomy and fusion, and provide scientific basis for the prevention and treatment of high-risk groups.
		                        		
		                        		
		                        		
		                        	
6.An email-based survey of treatment strategies in children with septic shock in China
Juan QIAN ; Suyun QIAN ; Chunfeng LIU ; Yibing CHENG ; Guoping LU ; Yucai ZHANG ; Xiaoxu REN ; Ying WANG
Chinese Pediatric Emergency Medicine 2022;29(10):790-795
		                        		
		                        			
		                        			Objective:To describe the treatment strategies in children with septic shock in China.Methods:A questionnaire was prepared and 368 pediatric intensivists from the Pediatric Critical Care Physician Branch of Chinese Medical Doctor Association were surveyed about the treatment of pediatric septic shock from April to June 2017.Results:Surveys were received from 87.2%(68/78) institutions and 368 questionnaires (response-rate 45.1%) were included.59.2% and 77.7% of the respondents chose debridement surgery and fluid drainage as source control intervention.Antibiotics were used within 1 hour of shock in 90.8% of respondents.98.4% of respondents chose normal saline, 72.3% of respondents chosen albumin, and 53.8% of respondents chosen plasma for fluid resuscitation.When no venous access was available during shock resuscitation, 57.1% of respondents preferred intraosseous access.79.3% and 83.2% of the respondents used the adjuvant therapy such as glucocorticoids and intravenous immunoglobulin.96.7%, 85.3% and 22.0% of respondents were likely to provide oxygen and mechanical ventilation, continuous renal replacement, and extracorporeal membrane oxygenation as organ support, respectively.Additionally, 322 (88.7%), 188 (51.1%), and 85 (23.1%) respondents chose the "best advice" options to simulated clinical cases of fluid resuscitation, inotropic agents, and vasoactive agents, respectively.In the simulated cases of vasoactive drugs and inotropic drugs, 69.3% and 24.2% of the respondents chose fluid resuscitation strategy, respectively.In cases of fluid resuscitation, 49.7% (183/368) of respondents reported performing fluid responsiveness and volume status assessment, and instruments used in the assessment included bedside echocardiography[39.4% (145/368)], bioreactance[10.3% (38/368)], transpulmonary thermodilution devices[6.3% (23/368)]. Pediatricians who received advanced life support courses for children ( P=0.006) and intensive care specialist training center training ( P=0.002) were more likely to choose the " best recommendation" option than those who did not attend the training. Conclusion:The current status of pediatric septic shock treatment strategies in China are active source control intervention, antibiotic use and organs support, and increased awareness of non-invasive hemodynamic monitoring.However, there may be excessive fluid infusion and inappropriate use of plasma, glucocorticoids and intravenous immunoglobulin.Different training and continuing education may improve rational treatment strategies.
		                        		
		                        		
		                        		
		                        	
7.A multi-center survey of medical staffs′ cognition and management of prolonged mechanical ventilation in pediatric intensive care unit
Pan LIU ; Zhengzheng ZHANG ; Yi ZHANG ; Hengmiao GAO ; Hong REN ; Dong QU ; Wei XU ; Chengjun LIU ; Hongjun MIAO ; Li HUANG ; Zihao YANG ; Furong ZHANG ; Yibing CHENG ; Guoping LU ; Weiming CHEN
Chinese Pediatric Emergency Medicine 2022;29(5):347-352
		                        		
		                        			
		                        			Objective:To investigate the status of cognition and clinical management of prolonged mechanical ventilation(PMV) among medical staffs in pediatric intensive care unit(PICU) in China, and in order to improve the awareness of PICU medical staffs on PMV and standardize the management of PMV.Methods:The cross-sectional study was conducted with doctors and nurses in PICUs of the collaborative group as the survey objects from July 12 to September 12, 2020.The questionnaire was issued, collected and checked by the Children′s Hospital of Fudan University.Results:(1) PMV related settings: Nine out of eleven hospitals had established PMV multidisciplinary teams, respiratory techniques such as diaphragm ultrasound and airway peak flow monitoring could be respectively executed in 72.7% and 36.4% of PICU.Pulmonary rehabilitation techniques such as airway clearance techniques, induced spirometer exercise, external diaphragm pacemaker stimulation, transfer bed exercise, balloon blowing, hyperbaric oxygen therapy could be respectively executed in 100.0%, 9.1%, 9.1%, 9.1%, 27.3% and 27.3% of PICU, respectively.(2) The cognitive status quo of children′s PMV: The most medical staffs agreed with the view that PMV referred to the children′s continuous mechanical ventilation for more than two weeks.Sixty percent of medical staffs believed that children with PMV had basic central nervous system diseases, and 62.7% of medical staffs believed that the most common causes of difficulty in PMV weaning was abnormal brain function.(3) The cognitive status quo of the children′s PMV management in PICU: Respondents believed that the most commonly used mechanical ventilation mode was synchronized intermittent mandatory ventilation+ pressure support ventilation in children′s PMV during stable disease.Ninety-two percent of medical staffs performed the spontaneous breathing test when weaning.And 58.7% of the respondents agreed to perform tracheotomy for the children during 3 to 4 weeks of mechanical ventilation.More than half of medical staffs would execute diaphragm function assessment, bedside rehabilitation training, nutritional assessment, analgesia and sedation assessment for children with PMV.(4) The cognitive status quo of the children′s PMV management of transition from hospital to family: 54.5% of PICU provided family care training to the family members before the children were discharged from the hospital.One center established the PMV specialized outpatient clinic.45.5% of PICU would follow up these discharged children one month later.Conclusion:At present, PICU medical staffs have different awareness of children′s PMV related problems in China.And children′s PMV lacks a systematic plan regarding diagnosis, treatment and management.
		                        		
		                        		
		                        		
		                        	
8.Validation the clinical value of good outcome following attempted resuscitation scores in Chinese populations in predicting the prognosis of in-hospital cardiac arrest
Yan REN ; Li YE ; Xia HUANG ; Xia GAO ; Guoping YIN ; Xiaofang WU ; Wenbin HUANG ; Linghong CAO ; Ping XU
Chinese Critical Care Medicine 2022;34(12):1238-1242
		                        		
		                        			
		                        			Objective:To verify the clinical value of the good outcome following attempted resuscitation (GO-FAR) score in predicting the neurological status of patients with in-hospital cardiac arrest (IHCA) in the Chinese population.Methods:The clinical data of patients with IHCA who were admitted to the Zigong Fourth People's Hospital from January 1 to December 31, 2020 were retrospectively analyzed. Used Glasgow-Pittsburgh cerebral performance category (CPC) score 1 point as the end point, the subjects were divided into 4 groups according to the score: ≤ 0 group, 1-8 group, 9-20 group and ≥ 21 group. Taken the group which GO-FAR score ≤ 0 as the reference group, the odds ratio ( OR) of the other three groups compared with this group was calculated. The receiver operator characteristic curve (ROC curve) was performed to evaluate the predictive value of the GO-FAR score in favorable neurological outcome. A calibration curve was drawn for the Hosmer-Lemeshow test to analyze the degree of calibration of the GO-FAR score for predicting good neurological outcome. Results:A total of 230 IHCA patients were enrolled in the study, including 130 males, aged 74 (65, 81) years old, and 23 case (10.0%) had good neurological prognosis. There were statistically significant differences in GO-FAR-related variables, including age, a normal neurological function on admitted, acute stroke, metastatic cancer, septicemia, medical noncardiac admission, hepatic insufficiency, hypotension, renal insufficiency or dialysis, respiratory insufficiency, pneumonia, etc (all P < 0.05). Taken the GO-FAR score ≤ 0 group as the reference group, the OR values of good neurological prognosis in the GO-FAR score 1-8 group were 0.54 [95% confidence interval (95% CI) was 0.17-1.53, P = 0.250], 9-20 group were 0.17 (95% CI was 0.02-0.67, P = 0.009) and ≥ 21 group were 0.25 (95% CI was 0.05-0.85, P = 0.025). The area under the ROC curve (AUC) of the GO-FAR score for predicting favorable neurological outcome in IHCA patients was 0.653 (95% CI was 0.529-0.777, P = 0.015) and there was no significant difference in Hosmer-Lemeshow test ( P = 0.311). All these suggested that there was no significant difference between the predicted value and the actual value. Conclusions:GO-FAR score can be applied to predict neurological prognosis of IHCA patients in Chinese population. It can help clinicians to predict the prognosis of cardio-pulmonary resuscitation (CPR) and propose critical recommendations in treatment for these patients or their families.
		                        		
		                        		
		                        		
		                        	
9.Study on the assignment method of intensity modulated radiotherapy plan for nasopharyngeal carcinoma based on MR images
Xinsen YAO ; Guanzhong GONG ; Jianxin REN ; Guoping ZUO ; Yong YIN
Chinese Journal of Oncology 2021;43(8):850-855
		                        		
		                        			
		                        			Objective:To discuss the influence of different computed tomography (CT) value assignment methods on dose calculation of intensity modulated radiotherapy (IMRT) plan which designed for nasopharyngeal carcinoma (NPC) and the value assignment methods of IMRT plan for NPC based on magnetic resonance (MR) images.Methods:Simulation CT and MR image of 32 NPC patients in Shandong Cancer Hospital from March 2018 to November 2018 were selected for this study. Populate CT values were obtained by contouring and analyzing the simulation CT of patients′ tissue, including bone, air, brain, eyeball, optic-nerve, lens, parotid, masseter, skin. Pseudo-CT were generated by different CT value assignment methods: CT1: CT value of all tissues was set to 0HU; CT2: CT value of air cavity was set to populate CT value based on CT1; CT3: CT value of Bone was set to populate CT value based on CT2; CT4: CT value of each soft tissue were set to populate CT value based on CT3. The IMRT plan for NPC as Plan0 was designed base on simulation CT. Then Plan0 was transplanted to four pseudo-CT to recalculate the dose and obtain Plan1, Plan2, Plan3 and Plan4, the differences of dosimetric parameters were compared with Plan0. NPC-IMRT plan was designed base on MR images by using the assignment method with CT value of each tissue were set to populate CT value.Results:In the head and neck CT images, the average populate CT values of bone and cavity were 621 HU and -720 HU, respectively. The populate CT values of other soft tissue ranges from -20 HU to 70 HU. The differences of dosimetric indexes of Plan1, Plan2, Plan3, Plan4 decreased sequentially compare to Plan0, the difference of the dosimetry parameters of Plan4 and Plan0 was the smallest. The differences of PTV D 99, PTV D 95, isocenter dose, D mean of all tissues, D max of bilateral eye balls, D max of bilateral lens, D max of bilateral optic nerves, D mean of bilateral parotid, V 20 of bilateral parotid, D 50 of bilateral parotid, D max of spinal cord, D max of brainstem, D 5 of brainstem between Plan4 and Plan0 were all less than 1%. The difference of V 30 in bilateral parotid between Plan4 and Plan0 was less than 1.5%. In the comparison of the pixel dose distribution, the regions of dose distribution difference greater than 1% mainly distributed in the air cavity, bone periphery and the skin. The target area of the IMRT plan for NPC based on MR images met 95% of the prescribed dose, and the dose of each organ at risk was within the dose limit. Conclusions:The assignment method of each tissue and organs set to populate CT value compared with other methods has the least influence on the dose calculation of NPC-IMRT plan, which could meet the clinical requirements. Therefore, it should be the first choice of assignment method when designing NPC-IMRT plan based on MR image.
		                        		
		                        		
		                        		
		                        	
10.Study on the assignment method of intensity modulated radiotherapy plan for nasopharyngeal carcinoma based on MR images
Xinsen YAO ; Guanzhong GONG ; Jianxin REN ; Guoping ZUO ; Yong YIN
Chinese Journal of Oncology 2021;43(8):850-855
		                        		
		                        			
		                        			Objective:To discuss the influence of different computed tomography (CT) value assignment methods on dose calculation of intensity modulated radiotherapy (IMRT) plan which designed for nasopharyngeal carcinoma (NPC) and the value assignment methods of IMRT plan for NPC based on magnetic resonance (MR) images.Methods:Simulation CT and MR image of 32 NPC patients in Shandong Cancer Hospital from March 2018 to November 2018 were selected for this study. Populate CT values were obtained by contouring and analyzing the simulation CT of patients′ tissue, including bone, air, brain, eyeball, optic-nerve, lens, parotid, masseter, skin. Pseudo-CT were generated by different CT value assignment methods: CT1: CT value of all tissues was set to 0HU; CT2: CT value of air cavity was set to populate CT value based on CT1; CT3: CT value of Bone was set to populate CT value based on CT2; CT4: CT value of each soft tissue were set to populate CT value based on CT3. The IMRT plan for NPC as Plan0 was designed base on simulation CT. Then Plan0 was transplanted to four pseudo-CT to recalculate the dose and obtain Plan1, Plan2, Plan3 and Plan4, the differences of dosimetric parameters were compared with Plan0. NPC-IMRT plan was designed base on MR images by using the assignment method with CT value of each tissue were set to populate CT value.Results:In the head and neck CT images, the average populate CT values of bone and cavity were 621 HU and -720 HU, respectively. The populate CT values of other soft tissue ranges from -20 HU to 70 HU. The differences of dosimetric indexes of Plan1, Plan2, Plan3, Plan4 decreased sequentially compare to Plan0, the difference of the dosimetry parameters of Plan4 and Plan0 was the smallest. The differences of PTV D 99, PTV D 95, isocenter dose, D mean of all tissues, D max of bilateral eye balls, D max of bilateral lens, D max of bilateral optic nerves, D mean of bilateral parotid, V 20 of bilateral parotid, D 50 of bilateral parotid, D max of spinal cord, D max of brainstem, D 5 of brainstem between Plan4 and Plan0 were all less than 1%. The difference of V 30 in bilateral parotid between Plan4 and Plan0 was less than 1.5%. In the comparison of the pixel dose distribution, the regions of dose distribution difference greater than 1% mainly distributed in the air cavity, bone periphery and the skin. The target area of the IMRT plan for NPC based on MR images met 95% of the prescribed dose, and the dose of each organ at risk was within the dose limit. Conclusions:The assignment method of each tissue and organs set to populate CT value compared with other methods has the least influence on the dose calculation of NPC-IMRT plan, which could meet the clinical requirements. Therefore, it should be the first choice of assignment method when designing NPC-IMRT plan based on MR image.
		                        		
		                        		
		                        		
		                        	
            
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