Dose estimation of radiopharmaceutical therapy is essential for the accurate evaluation of its efficacy and safety, as well as for guiding subsequent clinical research. The dosimetry estimation process typically requires understanding of the in vivo spatial distribution and dynamic transportation of radionuclides, followed by calculation of the energy deposition in tumor target volume and organs at risk from ionizing radiation of varying types and energies released by accumulated radionuclides. This review focuses on advancements in the aforementioned research aspects and the relationship between internal radiation dose and biological effects. Furthermore, this review prospectively discusses future research directions, aiming to enhance comprehension of internal radiation dose estimation and provides theoretical frameworks and technical references for improving clinical evaluation accuracy in radiopharmaceutical therapy.

Dose estimation of radiopharmaceutical therapy is essential for the accurate evaluation of its efficacy and safety, as well as for guiding subsequent clinical research. The dosimetry estimation process typically requires understanding of the in vivo spatial distribution and dynamic transportation of radionuclides, followed by calculation of the energy deposition in tumor target volume and organs at risk from ionizing radiation of varying types and energies released by accumulated radionuclides. This review focuses on advancements in the aforementioned research aspects and the relationship between internal radiation dose and biological effects. Furthermore, this review prospectively discusses future research directions, aiming to enhance comprehension of internal radiation dose estimation and provides theoretical frameworks and technical references for improving clinical evaluation accuracy in radiopharmaceutical therapy.

177Lu-prostate specific membrane antigen(PSMA)radio-ligand therapy has been approved abroad for advanced prostate cancer and has been in several clinical trials in China.Based on domestic clinical practice and experimental data and referred to international experience and viewpoints,the expert group forms a consensus on the clinical application of 177Lu-PSMA radio-ligand therapy in prostate cancer to guide clinical practice.

Objective:To estimate the lung cancer disease burden of residents caused by indoor radon exposure in living rooms in China, and to provide scientific basis for improving radon prevention and control policies and measures.Methods:Based on the data from the national indoor radon monitoring survey, the study of lung cancer caused by indoor radon, and the basic data such as population and smoking, the attributable burden of disease calculation method was used to estimate the disease burden of lung cancer caused by indoor radon in China.Results:In 2018, it was estimated that the years of life lost due to premature death (YLL), years of life lost due to health disability (YLD) and disability-adjusted life years (DALY) due to indoor radon exposure were 5.109 3 million, 0.052 6 million and 5.161 9 million, respectively. DALY was highest in the 50-54 age group. The disease burden of indoor radon-induced lung cancer in smoking men was more than 9 times that of smoking women, and the disease burden of lung cancer in non-smoking women was more than 5 times that of non-smoking men. Smoking is closely related to the disease burden of indoor radon-induced lung cancer.Conclusions:Indoor radon exposure is a major environmental risk factor associated with lung cancer burden in China. The health hazards of indoor radon require more attention and improved policy measures to address this challenge.

Objective:To estimate the lung cancer disease burden of residents caused by indoor radon exposure in living rooms in China, and to provide scientific basis for improving radon prevention and control policies and measures.Methods:Based on the data from the national indoor radon monitoring survey, the study of lung cancer caused by indoor radon, and the basic data such as population and smoking, the attributable burden of disease calculation method was used to estimate the disease burden of lung cancer caused by indoor radon in China.Results:In 2018, it was estimated that the years of life lost due to premature death (YLL), years of life lost due to health disability (YLD) and disability-adjusted life years (DALY) due to indoor radon exposure were 5.109 3 million, 0.052 6 million and 5.161 9 million, respectively. DALY was highest in the 50-54 age group. The disease burden of indoor radon-induced lung cancer in smoking men was more than 9 times that of smoking women, and the disease burden of lung cancer in non-smoking women was more than 5 times that of non-smoking men. Smoking is closely related to the disease burden of indoor radon-induced lung cancer.Conclusions:Indoor radon exposure is a major environmental risk factor associated with lung cancer burden in China. The health hazards of indoor radon require more attention and improved policy measures to address this challenge.

Objective:To develop a software for rapid estimation of external dose to the public due to environmental radioactive contamination.Methods:Based on the data provided by the International Commission on Radiological Protection (ICRP), a database of the conversion coefficients of external dose rates for the public (adult and children of different age groups) under different environmental exposure scenarios was created. The programs of data search and calculation were written using Python language, and the software interface was designed using PyQt toolkit. To test the calculation results, the differences in external doses to different age groups of the public caused by most likely produced radionuclides under three environmental exposure scenarios were calculated, and their rationalities were analyzed.Results:The software can immediately complete the estimation of the organ equivalent doses and the effective dose due to the external exposure form environmental contamination by using a personal computer with a Windows system, and its results are reasonable. The test results showed that the younger the public members, the larger the organ dose and effective dose. For soil surface and water contaminated with 90Sr with the same activity concentration reaching radioactive equilibrium, the effective dose to infants was about 6.08 times and 2.51 times those to adults, respectively. Conclusions:The software developed in this study has the advantages of simple operation and fast calculation, and is suitable for rapid estimation of external dose to the public members of different age groups in emergency situations such as nuclear accidents.

In recent years, the diagnostic radiology, especially CT scanning, has a rapidly increased frequency in our country, becoming the largest artificial radiation source to the average individual doses to the population. In clinical diagnosis and treatment activities, the examined patients and individuals may undergo multiple procedures and multiple frequencies of medical imaging in a short period of time and receive high cumulative radiation doses even exceeding 50 or 100 mSv in a single day, posing a potential risk to their health. Therefore, it is necessary to carry out statistical analysis and management of diagnostic radiation dose information to minimize the probability of excessive dose and associated radiation risk. In this paper, the international cognition of radiation risks in diagnostic radiology, diagnostic equipment and medical imaging frequency, radiation dose and its management status are described. Four countermeasures for radiation dose management are put forward to provide reference for further improving radiation protection in clinical practice.

Objective:To study the healthcare level (HCL) in China and its influencing factors.Methods:By using the data reported in the China statistical yearbook published by the National Bureau of Statistics and in other public literature, HCL was calculated in terms of the number of population and physicians in the whole country and various provinces. Multiple regression was used to analyze the relationship between HCL and regional population, area, number of administrative divisions and gross domestic product (GDP). Pearson correlation analysis was applied to analyze the relationship between healthcare level and medical radiation frequency. Results:Since 2015, Chinese HCL value was lower than 1 000, but there were two provinces with HCL value greater than 1 000 in 2019. Population and GDP were the influencing factors for the HCL, with correlation coefficients of 0.416 and -0.583, respectively. There was a correlation between HCL and medical exposure frequency of Chinese population( r= -0.620, P=0.028). Conclusions:Chinese HCL value was 542 in 2020, but there has been great differences between various provinces. HCL as an indicator of medical exposure assessment needs further research in China.

The radiation risk caused by CT examination is of great concern. Organ dose is considered to be the most significant technical parameter for quantifying the patient radiation dose and assessing the corresponding risk. At present, the methods to obtain patient organ dose caused by CT examination mainly include physical phantom measurement, direct human body measurement, dose conversion coefficient, Monte Carlo simulation, and dose calculation software. Although different methods have their own characteristics and application, the individualization of organ dose is always the goal of radiation protection and dosimetry research. Patient-specific phantom developed with artificial intelligence and GPU-accelerated Monte Carlo simulation make it possible to calculate the patient-specific organ dose, and the patient-specific organ dose extrapolated by the CT detector signal provides a new solution.

Objective To compare the precision and efficiency of computing the specific absorbed fraction (SAF) of a reference human with two grid methods in MCNP6.0. Methods Based on the adult female reference voxel phantom provided by the International Commission on Radiological Protection, assuming the liver as the source organ emitting single-energy photons (0.5 MeV), the SAF of each target organ/tissue was calculated by using the mesh method and repeated structure lattice method with the F4, F6, and *F8 tally cards in MCNP6.0. We compared the methods by assessing the relative deviation of SAF and computing time for 27 organs/tissues. Results Compared with reported data, the absolute values of relative deviations of SAF values for all the organs/tissues were less than 5%, except for the eye lens and skin. By using the repeated structure lattice-based *F8 tally, the relative deviations of SAF values of the organs/tissues were all smallest, but with the longest computing time. The computing time of the mesh-based F4 tally was slightly longer than that of the repeated structure lattice-based F6 tally, which was shortest. Conclusion The *F8 tally simultaneously simulating primary and secondary particle transport showed the highest precision. The mesh tally requireda longer computing time than the lattice tally when using the same tally card.