Objective To evaluate the influence of the wearing position of dosimeters outside lead aprons on effective dose estimation for interventional radiology workers, analyze the differences between single and double dosimeter methods in effective dose estimation, and provide a reference for the personal dose monitoring of interventional radiology workers. Methods This study employed a combined approach of on-site monitoring and Monte Carlo simulation to evaluate the impact of the wearing position of dosimeters outside lead aprons on effective dose estimation, as well as the differences between effective doses measured using single and double dosimeters. Interventional radiology workers wore dosimeters at three positions: the neck outside the lead collar, the left chest outside the lead apron, and inside the lead apron. Effective doses were estimated using the single and double dosimeter methods specified in GBZ 128-2019 Specifications for individual monitoring of occupational external exposure, and the impact of different wearing positions on the estimation results was compared. Geant4 Monte Carlo simulations were used to model dose distributions at the neck outside the lead collar and at the left chest outside the lead apron for operators performing cardiovascular interventions under tube voltages of 70, 80, 90, and 100 kVp and exposure angles of posteroanterior (PA), anteroposterior (AP), and left anterior oblique 45° (LAO45°) positions. The study assessed the impact of dosimeter wearing position on effective dose estimation. Results Monte Carlo simulations demonstrated that neck doses consistently exceeded left chest doses across different tube voltages and exposure angles, with neck-to-chest dose ratios of 0.80-0.90. Under identical tube voltage conditions, AP showed the highest doses, followed by LAO45°, and PA demonstrated the lowest doses. The single and double dosimeter methods exhibited consistent patterns in effective dose estimation. Single dosimeter method generally yielded higher effective doses with relative deviations of 9.9% to 83%, though these deviations decreased under high tube voltages. Field monitoring data indicated that most interventional radiology workers maintained relative deviations between single and double dosimeter calculations below 6%, with neck-to-chest dose ratios of 0.95-1.1. The estimation patterns remained consistent across both methods, though single dosimeter method showed slightly higher results. Conclusion Under PA, AP, or LAO45°, the doses at the neck consistently exceeded those at the left chest. Therefore, when wearing lead protective equipment, the dosimeter should be properly positioned at the neck outside the lead collar to accurately reflect the radiation doses of surgeons. Some interventional radiology workers improperly positioned the dosimeter (intended at the neck outside the lead collar) at the left chest outside the lead apron, and this may result in an underestimation of the effective dose.

Objective To observe the inhibitory effect of Tirofiban on different shear-induced platelet aggregation, and to provide medication suggestions for the treatment of thrombosis in different hemodynamic environment. Methods Polydimethylsiloxane ( PDMS)-glass microchannel chips were fabricated by soft lithography. The whole blood of healthy volunteers anticoagulated with sodium citrate was collected and incubated with different concentrations of Tirofiban in vitro. The blood flowed through the straight microchannel or channel with 80% narrow for 150 seconds at the speed of 11 μL/ min and 52 μL/ min, respectively. The wall shear stress rates in straight channel at 11 μL/ min and 52 μL/ min were 300 s-1 and 1 500 s-1, respectively. The maximum wall shear rates in the channel with 80% occlusion at 11 μL/ min and 52 μL/ min were 1 600 s-1 and 7 500 s-1, respectively. The adhesion and aggregation images of fluorescent labeled platelets on glass surface were photographed with the microscope, and the fluorescent images were analyzed with Image J. The platelet surface coverage ratio was used as a quantitative index of platelet aggregation behavior, and the IC50 of Tirofiban for platelet inhibition was calculated under different shear rates. Flow cytometry was used to detect the platelet activation index (CD62P, PAC-1) in the whole blood at 52 μL/ min in channel with 80% occlusion. Results Tirofiban inhibited platelet aggregation in a dose-dependent manner, and the inhibitory effect was related to the shear rate. Under the shear rates of 11 μL/ min and 52 μL/ min, the aggregation was almost completely inhibited when the concentration in straight channel reached 100 nmol / L. When the concentration in channels with 80% occlusion reached 1 μmol / L, the aggregation was almost completely inhibited. IC50 values at 11 μL/ min and 52 μL/ min in straight channel were 2. 3 nmol / L and 0. 5 nmol / L, respectively. IC50 values at 11 μL/ min and 52 μL/ min in channels with 80% occlusion were 20. 73 nmol / L and 4. 5 nmol / L. Pathologically high shearforce induced an increase in platelet activation, which could be inhibited by Tirofiban. Conclusions Tirofiban can effectively inhibit shear-induced platelet aggregation, and different concentrations of Tirofiban should be given according to the thrombus formed in different shear force environment in clinic practice

To investigate the distribution of hepatitis B virus (HBV) genotypes and subgenotypes among the Bai nationality in Dali, a total of 100 serum samples from patients with chronic HBV-infection were collected for the detection of HBV genotypes and subgenotypes by genotype-specific primers and restriction fragment length polymorphism (RLFP), respectively. Among the 100 samples, the proportions of genotype B, C and mixed genotype (B+C) were 41%, 25% and 34%, respectively. All the genotype B strains belonged to subgenotype Ba. In genotype C, 84% were Subgenotype Cs and 12% were subgenotype Ce. The distribution of genotypes B, C and B+C showed no significant difference between male and female patients (P=0.182) and among the age groups of patients (P=0.812). The rates of HBeAg/HBeAg positivity were no significantly different among genotypes B, genotype C and mixed genotype (B+C) (P=0.077/P=0.663). In Dali, genotypes B, B+C and C existed among Bai nationality with chronic HBV-infection, and genotype B was the major genotype. Subgenotypes Ba and Cs were the predominant strains in patients with HBV genotype B/C infection. The most prominent characteristic was the higher prevalent rate of mixed genotype (B+C) in patients.