No-Carrier-Added Lutetium-177 Separation Technology Status

Medical isotopes are the substantial basis of the diagnostic and therapeutic nuclear medicine. There are irreplaceable advantages for utilizing the nuclear medical technology to diagnose and treat the malignant tumors, cardiovascular and cerebrovascular diseases, neurodegenerative diseases and other major diseases. Lutetium-177 (177Lu) has excellent nuclear physical and chemical properties. In recent years, 177Lu has been widely used in the research and clinical application of targeted nuclide therapy in the western developed countries, and the radio-labeled compounds have showed the good effects in the diagnosis and treatment of tumors, including neuroendocrine tumors, prostate cancer, metastatic disease in bone and etc. 177Lu has been recognized as one of the most promising and dynamic economical theranostic targeted medical radio-isotopesand the global demand for 177Lu can be expected to grow explosively in the future. In this text, the preparation principle of 177Lu and current research status of 177Lu separation technology domestically or internationally, the future market demand and the application prospect were briefly introduced

Analysis for Friction Heating Power of Non-lubricated Auxiliary Bearing of Electromagnetic Bearing during Rotor Drop

In order to predict the life of the auxiliary bearing in the design stage, it is crucial to calculate the friction heating power of the auxiliary bearing during the rotor drop process. In many cases, the auxiliary bearing has no lubrication or only solid lubrication. Therefore, the local method was chosen to calculate the friction power, focusing on analyzing the rolling elastic hysteresis power between the ball and raceway, the spin power of the ball and the differential sliding power between the ball and raceway. The calculation formulas of these powers were provided in this paper, along with the derivation of an analytical formula for the differential sliding power, which facilitates practical applications. These formulas are based on the quasi-static analysis and the raceway control theory. When the rotation speed of the inner ring of the auxiliary bearing, the radial force acting on the auxiliary bearing and the axial preloading force are all known, the friction heating power of the auxiliary bearing can be calculated by these formulas. The free drop experiment of an electromagnetic bearing high-speed motor without braking was carried out to test the calculation, under 3 000, 5 400, and 6 600 r/min. The rotor axis trajectory and the horizontal and vertical impact force acting on the auxiliary bearing were measured. The rotation speed of the inner ring of the auxiliary bearing was assumed to be the same as the speed of the rotor, calculated by the rotor axis trajectory. The radial force acting on the auxiliary bearing was calculated based on the horizontal and vertical impact force. The axial preloading force, which is about 410 N in this paper, was determined by the experimental data under 3 000 r/min with the method of trial calculation. With these parameters, the friction heating power of the auxiliary bearing was calculated, and compared with the change rate of the kinetic energy of the rotor observed in the experiment. It is found that the heating power calculated by the local method is approximately equivalent to the change rate of the kinetic energy, which proves the feasibility of the theoretical calculation. During the drop process of a non-lubricated auxiliary bearing, the spin of the ball generates the most heat, followed by the differential sliding between the ball and the raceway. The sum of the two accounts for the main part of the total heat, and the rolling elastic hysteresis between the ball and the raceway generates less heat

Research on Automatic Measurement Method of Three-dimensional Gamma Dose Rate Radiation Field Based on VSLAM

To address the need for rapid acquisition of gamma radiation field information in nuclear facility sites and digital radiation protection systems, simultaneous localization and mapping (SLAM) technology was combined with gamma dose detection technology in this paper. This combination aims to solve the problem of efficiently measuring gamma dose rate radiation fields in indoor scenarios while ensuring compatibility with digital systems. The study leverages the characteristics of scene sensors, focusing on visual SLAM (VSLAM) algorithms and methods for synchronizing and locating radiation measurement data using an RGBD camera. A gamma dose rate measurement device based on VSLAM was developed, employing an RGBD camera to capture the device motion trajectory and scene information. The gamma dose rate data was temporally and spatially matched with the trajectory test data by utilizing timestamps and the integral path midpoint method. This approach ensures precise synchronization between the spatial data from the VSLAM system and the temporal data from the gamma dose measurements. The quality of the scene point cloud, the accuracy of trajectory localization, and the performance of the gamma dose rate detection module were thoroughly tested. The measurement efficiency, localization accuracy, and compatibility with digital systems were analyzed at the experiments conducted at a nuclear facility site. The results show that more than 80% of the VSLAM scene point cloud matches the reference point cloud with a nearest neighbor distance of less than 0.2 m. This high level of accuracy in point cloud matching indicates that the VSLAM system can reliably reconstruct the 3D environment of the nuclear facility. The average matching distance between the measured trajectory and the motion capture system trajectory is 4.2 cm, with a standard deviation of 0.4 m. This demonstrates the high precision of the trajectory localization achieved by the VSLAM system. Within a dose rate range of 20 μGy/h to 20 mGy/h, the relative error in dose rate measurement is less than ±5%, indicating the reliability of the gamma dose detection module. Compared to traditional measurement methods, the new method improves the measurement efficiency of radiation dose rate fields by 10 times. This significant enhancement in efficiency can greatly reduce the time and effort required for radiation monitoring in nuclear facilities. The average matching distance between the measured trajectory and traditional tracking equipment (total station) was 18 cm, further validating the accuracy of the SLAM-based approach. Integration with digital systems achieves 3D spatial interpolation of radiation fields, with a single gamma source localization error of less than 0.8 m. This integration allows for a comprehensive visualization and analysis of radiation fields, facilitating better decision-making for radiation protection and safety. The developed VSLAM gamma dose rate measurement method and corresponding device offer high measurement efficiency, accurate localization, and good compatibility with digital systems, indicating a broad application prospect in the field of nuclear safety and radiation protection