Objective To establish a stable and reliable model of brain death in swine, and to provide a more stable model for investigating pathomorphology in brain tissue and for studying transplantation immunology during brain death. Methods Base on the classic methodology of increasing epidural intracranial pressure, Codman intracranial pressure moni-toring probes were implanted in landrace pigs invasively. According to the relationship between ICP and MAP, brain death models were established by increasing intracranial pressure slowly and intermittently, with real-time monitoring of the intra-cranial pressure. Results Among twelve experimental landrace pigs, one died from anesthetic accident, while the rest elev-en were successfully established as brain death models. With effective respiratory and circulatory support, those brain death models can be maintained for (31.3 ± 4.7) h. Brain death model establishement is a stable and reliable process demonstrated by transcranial Doppler, EEG, ECG, mean arterial blood pressure and other monitoring methods. After brain death is con-firmed, animal models can be maintained for a long time. Conclusion Our methodology of inducing brain death model un-der ICP monitoring is stable and easy to be standardized. It can also provide a more stable model for studying brain tissue pathomorphology and transplantation immunology.

Objective To explore the risk factors affecting the prognosis of patients with small bowel adenocarcinoma(SBA),construct the SBA survival risk model,and evaluate the clinical predictive value.Methods Clinical information and prognosis data of 2 639 patients included in the surveillance,epidemiology,and end results(SEER)database were retrospectively analyzed.Overall survival(OS)and disease specific survival(DSS)were used as prognostic indicators.The training group and validation group were randomized at a 7 ∶ 3 ratio using univariate and multivariate Cox regression analysis.Prognostic factors affecting SBA sur-vival were screened,and a prognostic prediction model was constructed.The receiver operation characteristic curve,model valida-tion by validation group,and clinical decision curve.Results Age(P<0.01),tumor site(P = 0.018),size(P = 0.042),T stage(P<0.01),detection rate of positive lymph nodes(P<0.01),single tumor focus(P<0.01),and secondary liver metastasis(P<0.01)were independent risk factors affecting prognosis of OS in patients with SBA;age(P<0.01),tumor size(P= 0.022),T stage(P<0.01),detec-tion rate of positive lymph nodes(P<0.01),single tumor focus(P<0.01),and secondary liver metastasis(P<0.01)were independent risk factors affecting the prognosis of DSS in patients with SBA.The nomogram,survival risk assessment model,and calibration prediction curve were consistent with the actual curve.Conclusion Age,tumor size,T stage,detection rate of positive lymph nodes,single tumor focus,and secondary liver metastasis were independent risk factors for OS and DSS in patients with SBA.Tumor site was also an inde-pendent risk factor for OS in SBA patients.The established prognostic prediction model has good predictive value,can effectively evaluate the prognosis of SBA patients,and can provide reasonable treatment advice for patients.

Objective:To construct back propagation (BP) neural network model to predict the dose required for 131I therapy for hyperthyroidism and to calculate the personalized dose plan for patients. Methods:A complete set of data of patients treated for hyperthyroidism radioaiodine was collected from the nuclear medicine departments of several medical colleges in Shanghai, including history, examination result, treatment course, etc. As a result, a prediction model was established. The predicated result for BP neural network, radial basis function (RBF) neural network and Support Vector Machine (SVM) were compared by means of small sample data. The optimal model was selected to predict administrated dose and to finally test the accuracy of the model.Results:The average errors in BP neural network, RBF neural network and SVM model based on small samples were 5.53%, 7.09% and 9.64%, respectively. After comparison, BP neural network was selected to build the prediction model. 30 cases of data were selected by random sampling to verify the BP neural network. The mean error, mean square error, minimum error and maximum error of the prediction result were 7.22%, 0.053, 0.57% and 13.78%, respectively.Conclusions:In this study, a neural network prediction method was proposed to provide a more accurate dose for patients in need of radioiodine therap for hyperthyroidism, and to reduce the possibility of radiation damage or the unsatisfactory therapeutic effect caused by insufficient dose. It has clinical practical significance in providing the reference for clinicians to evaluate the administrated dose.

Objective:To establish a HPLC method for determinating 9 components simultaneously in Swertia chirayita. Methods:By useing water Sunfire C18 column (4.6 mm× 250 mm,5 μm); Gradient elution was carried out with methanol-0.05% phosphoric acid solution as mobile phase. Setting the column temperature at 30 ℃, the flow rate at 1.0 ml/min, and the detection wavelength at 254 nm.Results:9 components showed good linear relationship within the injection quality range. The recovery rates of wertiamarin, Gentiopicroside, Angelica glycosides,Mangiferin, Isolysine, Gentianoside, Diol glycoside, 8-hydroxy-1,3,5 trimethoxyketone, and Daisy leaf gentinone were 95.38%, 92.41%, 95.14%, 91.87%, 92.24%, 92.51%, 95.08%, 91.72%, 95.74% ( n=6). Conclusion:The method is simple, efficient, sensitive, accurate, economical and practical, with repeatability and stability. It could provide reference for the quality control and comprehensive utilization of Swertia chirayita.

Objective To investigate the quality control and protection level of medical electron linear accelerators in Shanghai, China. Methods The startified random sampling method was used to cover tertiary, secondary and ungraded hospitals, and a total of 30 medical electron linear accelerators in 15 hospitals were tested for quality control and protection level according to relevant standards. Results Five medical electron linear accelerators failed the quality control test, with an overall inspection pass rate of 83.3% and a re-inspection pass rate of 100%. The pass rate of flatness of square X-ray irradiation field (5 cm × 5 cm)-(30 cm × 30 cm) was 83.3%, the pass rate of symmetry of square X-ray irradiation field was 96.7%, and other indices were qualified. All medical electron linear accelerator rooms passed the protection test. Conclusion The protection of medical electron linear accelerator rooms in Shanghai meets the requirements of national standards, and some indices do not meet the requirements of national standards in the preliminary inspection. The quality control of medical electron linear accelerators should be further strengthened to ensure the treatment effect of patients.

Background Individual monitoring of occupational external exposure is an essential part of the occupational health management of radiation workers, and is an important basis for the evaluation of individual absorbed dose and the diagnosis of occupational radiation diseases. Continuous participation of monitoring service providers in intercomparison is a fundamental quality assurance for routine monitoring, which can identify problems and improve them in time. Objective Taking the Laboratory of Radiation Protection in Shanghai Institute of Preventive Medicine as an example, to evaluate the performance of an individual occupational external dose monitoring system in the laboratory, identify influencing factors of the monitoring results, and provide a basis for improving the quality of daily monitoring by analyzing the process and results of a national intercomparison of individual dose monitoring. Methods According to the Testing criteria of personnel dosimetry performance for external exposure (GBZ 207-2016), and the relevant requirements of Class II (photon) inspection, a total of 20 groups of blind sample dosimeters were measured for four consecutive years from 2018 to 2021. The radiation energy source of each group was identified, and related personal dose equivalent H_p(10), the uncertainty of measurement results, and the deviation between the reported value and the reference value were calculated. The national intercomparison process and results of individual dose monitoring were also analyzed. Results The energy sources of the blind samples in the tested laboratory for four years were N100 or Cs-137. The reported dose values of the blind samples were 0.57-4.61 mSv, the combined uncertainties were 0.043-0.365 mSv, the expanded uncertainties (k=2) were 0.09-0.73 mSv, and the relative expanded uncertainties (k=2) were 13.8%-16.4%. The single-group performance ∣P_i∣ of 20 sets of blind samples in the four years was ≤0.10, the yearly comprehensive performance of 5 sets of blind samples was ≤0.10, and the yearly Q score of the test report was >15 points. The laboratory achieved excellent results in the national intercomparison of individual dose monitoring in four consecutive years, except the Q value not reaching full score. Conclusion The laboratory exhibits standardized data processing of individual dose monitoring, generates accurate and reliable results, and meets the requirements of relevant national standards; but it should continue to participate in the national intercomparison of individual dose monitoring, strengthen the angular response research of energy identified dosimeter, improve the monitoring ability of low-dose X-rays, analyze the key points of reducing the uncertainty of measurement results, and continuously improve the monitoring ability.