Objective:To investigate the performance of W2 plastic scintillator in megavolt photon and electron beams.Methods:The photon and electron beam energy provided by linear accelerator was used to collect data of the W2 scintillator. The parameters include the electrometer reading stability, W2 dose and dose rate linearity, and angular response. And the dose uncertainty of the W2 correction factors was also investigated.Results:The standard deviation of the electrometer reading stability was between 0.03 and 0.47. The linear regression factors of W2 dose were all 1.0; the maximum deviation of the dose rates was 0.61%. The Cerenkov light radiation correction factor(CLR) for 6 and 10 MV were 0.741 and 0.746, respectively, and the CLR for 6, 9, 12 and 15 MeV were 0.750, 0.753, 0.757 and 0.757, respectively. The maximum deviation of dose uncertainty for 15 MeV was 3.15%.Conclusions:The signal obtained by the blue and green channel was no angular dependence, the same as the high-energy electron beam, which verified that the Cerenkov radiation correction factor has good linearity. W2 plastic scintillator can be applied to non-coplanar radiotherapy dosimetry.

Objective:To explore the efficacy of fluorescent retroperitoneal lymph node dissection in the comprehensive treatment of lymph node recurrence after radical prostatectomy (RP).Methods:From January 2017 to December 2020, 25 patients with lymph node recurrence diagnosed by 68Ga-PSMA PET/CT after RP in our hospital were enrolled in this study. The patients were 67 (59-77) years old. The median PSA was 7.7 (0.5-12.6) ng/ml at lymph node recurrence, and was treated with androgen deprivation therapy (ADT), suggesting hormone-sensitive prostate cancer. Before recurrence, 4 cases were in T 2 stage, 17 cases in T 3, 4 cases in T 4, 10 cases in N 0, and 15 cases in N 1stage, 25 cases in M 0stage. 2 cases diagnosed as ISUP grade group <3, 9 cases in group 4, and 14 cases in group 5. The median time from radical resection to recurrence was 43 (27-56) months. All 25 cases were diagnosed as lymph node recurrence by 68Ga-PSMA PET/CT examination. Fluorescence retroperitoneal lymph node dissection was performed. Pelvic lymph nodes were detected in the dark field under the fluorescence mode, and positive lymph nodes were found. The white light mode was switched, and the lymph nodes were cleaned, and recorded. For metastatic lymph nodes indicated by preoperative PSMA PET/CT, routine dissection was performed regardless of whether the lymph nodes were fluorescently positive or not. The only routine examination was performed if there were no lymph nodes with fluorescently positive staining in other sites. Perioperative data, biochemical recurrence (BCR) rate, radiological recurrence (RAR) rate, and follow-up data were collected and analyzed. Results:25 patients were pathologically diagnosed with lymph node metastasis. The median lymph node dissection time was 21(15-28) min, estimated blood loss was 30(20-50) ml, hospital days was 4(3-5)d without any severe complications (

Objective To compare the impact of immobilization base plates composed of 7 types of materials on the MR-simulation imaging quality used for radiotherapy,aiming to provide reference data for clinical applications.Methods Using identical T1 and T2 sequences of Siemens MR-simulator,the MR images of ACR Large Phantom were acquired on the Orfit carbon fiber laminate,polycarbonate (PC),high precision base plate (HP),Jinan Huayuxin BR,WR,KP and SP materials,respectively.The imaging quality without any plate was used as the baseline data.The following metrics were compared:1.High-contrast spatial resolution:the sharpness of 3 pairs of hole arrays was observed,which represented resolutions of 1.1 mm,1.0 mm and 0.9 mm on the LR and AP directions;2.Image intensity uniformity in terms of percent integral uniformity (PIU):PIU =100× [1-((high-low)/(high +low)];3.Low-contrast resolution:distinguishable spokes representing resolutions of 5.1％,3.6％,2.5％ and 1.4％ were recorded.According to ACR recommendations,high-contrast resolution of 1.0 mm,PIU of T1WI and T2＞82％and low-contrast spoke difference＜3 were considered as clinically acceptable.Results High-contrast T1WI and T2WI resolutions of no plate,PC plate,HP plate and KP material were all 0.9 mm,and those of the remaining materials were =worse than 0.9 mm.The T1WI and T2WI PIU of no plate was＞87％,and the PIU of carbon fiber plate was reduced by＞ 25％.The PIU decrease of remaining materials was within ±4％.Except the carbon fiber plate,the low-contrast spokes of the remaining materials were within ±3 compared with the reference.Conclusions In clinical settings,carbon fiber plate exerts the most significant effect upon the MR-simulation imaging quality,which is unsuitable for MR simulation.Imaging quality of PC and HP plates are consistent with that of no plate.BR and KP materials exert slight effect upon MR signal.The remaining materials are of potential values for the manufacture of immobilization devices and accessories.

Objective:To investigate the etiology,clinical features and prognosis of pediatric liver retransplantation.Methods:The data of 1 024 cases of pediatric liver transplantation (<18 years old) from January 2014 to December 2019 operated at Tianjin First Central Hospital were collected,retrospectively. Retransplantation was performed in 26 cases,among which 25 cases received secondary liver transplantation and 1 case received a third liver transplantation. There were 13 male and 12 female patients among the 25 patients. The median age was 12.9(20.5) months(range: 5.8 to 134.8 months), the body weight was 8.0(5.6) kg(range: 5.0 to 30.0 kg) at the time of retransplantation. The pediatric end-stage liver disease(PELD) score was 17.0(21.3) (range: 0 to 45) before retransplantation. The etiology of retransplantation was biliary complications in 7 cases,primary nonfunction of liver graft in 5 cases,antibody-mediated rejection in 4 cases,hepatic artery thrombosis in 3 cases,portal vein thrombosis in 3 cases,concomitant hepatic artery and portal vein thrombosis in 2 cases,thrombogenesis of inferior Vena Cava in 1 case and sinusoidal obstruction syndrome in 1 case. The patients were divided into two groups according to the time interval(30 days) between two liver transplantations,8 patients were classified into early-retransplantation(≤30 days) group and 18 patients were classified into late-retransplantation (>30 days) group. The etiology of liver retransplantation,pre-transplant score,time interval between two transplantations,surgical aspects,major complications and survival rates were compared between the two groups. Continuous variables with normal distribution were compared with t test,while Mann-Whitney U test was applied to compare variables without normal distribution. Categorical variables were compared with chi-square test. The survival curves were created by Kaplan-Meier method and compared by Log Rank test. Results:The median follow-up time was 26.8(30.2) months(range: 1 day to 85.7 months), and the incidence of retransplantation was 1.9%. In the early-retransplantation group,the duration of surgery was (439.8±151.0)minutes,the graft-to-recipient weight ratio was 5.0(1.8)%(range:3.6% to 6.1%),the main cause for retransplantation were primary nonfunction and vascular complications. In the late-retransplantation group,the duration of surgery was (604.4±158.0)minutes,the graft-to-recipient weight ratio was 3.4(2.1)%(range:1.4% to 5.3%),the main cause for retransplantation were biliary complications,antibody mediated rejection and vascular complications.The 3-month,1-year and 2-year recipient survival rates in the early-retransplantation group were all 62.3%,while the recipient survival rates in the late-retransplantation group were 100%,93.8% and 93.8%,respectively. The difference of recipient survival rates was significant between the early-retransplantation group and the late-retransplantation group( P=0.019). The overall 3-month,1-year and 3-year recipient survival rates after the primary liver transplantation were 97.1%,95.4%,94.1%,respectively. Conclusions:The vascular complications,biliary complications,primary nonfunction and antibody-mediated rejection are the main causes of liver retransplantation.The PELD score is higher in patients receiving early retransplantation,while the surgery is relatively more complex in patients receiving late retransplantation,which is reflected by longer duration of surgeries. Patients in the late-retransplantation group showed similar recipient survival rates with primary liver transplantation recipients,and the survival rates are superior to those of patients in the early-retransplantation group. Infection and multiple organ failure are the most common fatal causes after retransplantation.

Objective:To investigate the etiology,clinical features and prognosis of pediatric liver retransplantation.Methods:The data of 1 024 cases of pediatric liver transplantation (<18 years old) from January 2014 to December 2019 operated at Tianjin First Central Hospital were collected,retrospectively. Retransplantation was performed in 26 cases,among which 25 cases received secondary liver transplantation and 1 case received a third liver transplantation. There were 13 male and 12 female patients among the 25 patients. The median age was 12.9(20.5) months(range: 5.8 to 134.8 months), the body weight was 8.0(5.6) kg(range: 5.0 to 30.0 kg) at the time of retransplantation. The pediatric end-stage liver disease(PELD) score was 17.0(21.3) (range: 0 to 45) before retransplantation. The etiology of retransplantation was biliary complications in 7 cases,primary nonfunction of liver graft in 5 cases,antibody-mediated rejection in 4 cases,hepatic artery thrombosis in 3 cases,portal vein thrombosis in 3 cases,concomitant hepatic artery and portal vein thrombosis in 2 cases,thrombogenesis of inferior Vena Cava in 1 case and sinusoidal obstruction syndrome in 1 case. The patients were divided into two groups according to the time interval(30 days) between two liver transplantations,8 patients were classified into early-retransplantation(≤30 days) group and 18 patients were classified into late-retransplantation (>30 days) group. The etiology of liver retransplantation,pre-transplant score,time interval between two transplantations,surgical aspects,major complications and survival rates were compared between the two groups. Continuous variables with normal distribution were compared with t test,while Mann-Whitney U test was applied to compare variables without normal distribution. Categorical variables were compared with chi-square test. The survival curves were created by Kaplan-Meier method and compared by Log Rank test. Results:The median follow-up time was 26.8(30.2) months(range: 1 day to 85.7 months), and the incidence of retransplantation was 1.9%. In the early-retransplantation group,the duration of surgery was (439.8±151.0)minutes,the graft-to-recipient weight ratio was 5.0(1.8)%(range:3.6% to 6.1%),the main cause for retransplantation were primary nonfunction and vascular complications. In the late-retransplantation group,the duration of surgery was (604.4±158.0)minutes,the graft-to-recipient weight ratio was 3.4(2.1)%(range:1.4% to 5.3%),the main cause for retransplantation were biliary complications,antibody mediated rejection and vascular complications.The 3-month,1-year and 2-year recipient survival rates in the early-retransplantation group were all 62.3%,while the recipient survival rates in the late-retransplantation group were 100%,93.8% and 93.8%,respectively. The difference of recipient survival rates was significant between the early-retransplantation group and the late-retransplantation group( P=0.019). The overall 3-month,1-year and 3-year recipient survival rates after the primary liver transplantation were 97.1%,95.4%,94.1%,respectively. Conclusions:The vascular complications,biliary complications,primary nonfunction and antibody-mediated rejection are the main causes of liver retransplantation.The PELD score is higher in patients receiving early retransplantation,while the surgery is relatively more complex in patients receiving late retransplantation,which is reflected by longer duration of surgeries. Patients in the late-retransplantation group showed similar recipient survival rates with primary liver transplantation recipients,and the survival rates are superior to those of patients in the early-retransplantation group. Infection and multiple organ failure are the most common fatal causes after retransplantation.

Food impaction with tight proximal contacts, also known as kinetic food impaction and food impaction without anatomical structure destruction, is mainly caused by a transient separation in contacts area during mastication. It′s an intractable food impaction with high morbidity and low cure rate. There are two kinds of pathogenesis accepted: the shifting of anterior teeth incongruous with adjacent teeth or lack of anterior shifting; lack of food escape grooves. The preferred treatment is occlusal adjustment, but it′s difficult to determine the area and extent of selective grinding, to quantify the occlusal adjustment, or to predict the prognosis. This review summarized the pathogenesis and treatment modality for kinetic food impaction in order to provide evidence for future researches and clinical application.

OBJECTIVE：To study the pr otective effect of schisandrin A （SA）on CCl 4-induced liver fibrosis model mice and its mechanism. METHODS ：Mice were randomly divided into blank control group ，model group ，silymarin group （positive control，100 mg/kg），SA low-dose and high-dose groups （20，40 mg/kg），with 10 mice in each group. Except for blank control group，other groups were given CCl 4 subcutaneously to induce liver fibrosis model. After successful modeling ，administration groups were given relevant medicine intragastrically ，once a day ，for consecutive 6 weeks；blank control group and model group were given constant volume of 0.5％sodium carboxymethyl cellulose solution intragastrically by the same way. HE staining was used to observe the pathological changes of liver tissue in mice. UV spectrophotometry and ELISA assay were adopted to detect the serum levels of liver injury indexes （ALT and AST ）and the contents of inflammatory factors （TNF-α，IL-1β，IL-6）. Western blotting assay was used to detect the expression of NOD like receptor protein 3（NLRP3）/NF-κB and TGF-β/Smad signaling pathway protein. RESULTS ：Compared with blank control group ，obvious pathological changes of liver fibrosis were observed in model group. The serum levels of liver injury indexes and contents of inflammatory factors were significantly increased （P＜0.01）. The expression of NLRP 3，apoptosis associated spot-like protein ，Caspase-1 and IL- 1β，TGF-β1 and ratios ofp-NF-κB p65/NF-κB p65，p-IκBα/IκBα，p-Samd3/Smad3 were increased significantly （P＜0.01）. Compared with model group ，SA could significantly relieve hepatic fibrosis in mice ，reduce serum levels of liver injury indexes and contents of inflammatory factors ，as well as the expression of NLRP 3/NF-κB and TGF-β/Smad signaling pathway protein and phosphorylation level（P＜0.01）. CONCLUSIONS ： SA can effectively relieve liver injury and inflammation of CCl 4-induced hepatic fibrosis model mice ，which may be through the regulation of NLRP 3/NF-κB and TGF-β/Smad3 signaling pathways ，thus inhibiting the process of liver fibrosis.