Targeted lipidomics-based study of radiation-induced metabolite profiles changes in plasma of total body irradiation cases.

PURPOSE: Lipidomics is an important tool for triaging exposed individuals, and helps early adoption of prevention and control strategies. The purpose of this study was to screen significantly perturbed lipids between pre- and post-irradiation of human plasma samples after total body irradiation (TBI) and explore potential radiation biomarkers for early radiation classification. METHODS: Plasma samples were collected before and after irradiation from 22 hospitalized cases of acute myeloid leukemia (AML) prepared for bone marrow transplantation. Acute total-body γ irradiation was performed at doses of 0, 4, 8, and 12 Gy. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with multiple reaction monitoring (MRM) method was utilized. Self-paired studies before and after irradiation were performed to screen potential lipid categorization markers and markers of dose-response relationships for radiation perturbation in humans. Based on the screened potential markers, a human TBI dose estimation model was developed. RESULTS: In total, 426 individual lipids from 14 major classes were quantified and 152 potential biomarkers with categorical characteristics were screened. A total of 80 lipids (32 TGs, 29 SMs, 9 FAs, 5 CEs, 5 PIs) were upregulated at 4 Gy, and a total of 91 lipids (39 SMs, 18 TGs, 15 HexCers, 7 CEs, 6 Cers, 3 LacCers, 2 LPEs, 1 PI) were upregulated at 12 Gy. Comparison of the ROC curves between the non-exposed and exposed groups at different doses showed AUC values ranging from 0.807 to 0.876. The metabolic pathways of potential lipid markers are mainly sphingolipid and glycerolipid metabolism, unsaturated fatty acid biosynthesis, fatty acid degradation and biosynthesis. Among the 13 dose-dependent radiosensitive lipids, CE (20:5), CE (18:1) and PI (18:2/18:2) were gradually incorporated into the TBI dose estimation model. CONCLUSION: This study suggested that it was feasible to acquire quantitative lipid biomarker panels using targeted lipidomics platforms for rapid, high-throughput triage. Lipidomics strategies for radiation biodosimetry in humans were established with lipid biomarkers with good dose-response relationship.

Quantitative analysis of radiosensitizing effect for magnetic hyperthermia-radiation combined therapy on prostate cancer cells.

BACKGROUND: Magnetic hyperthermia (MHT) has emerged as a promising therapeutic approach in the field of radiation oncology due to its superior precision in controlling temperature and managing the heating area compared to conventional hyperthermia. Recent studies have proposed solutions to address clinical safety concerns associated with MHT, which arise from the use of highly concentrated magnetic nanoparticles and the strong magnetic field needed to induce hyperthermic effects. Despite these efforts, challenges remain in quantifying therapeutic outcomes and developing treatment plan systems for combining MHT with radiation therapy (RT). PURPOSE: This study aims to quantitatively measure the therapeutic effect, including radiation dose enhancement (RDE) in the magnetic hyperthermia-radiation combined therapy (MHRT), using the equivalent radiation dose (EQD) estimation method. METHODS: To conduct EQD estimation for MHRT, we compared the therapeutic effects between the conventional hyperthermia-radiation combined therapy (HTRT) and MHRT in human prostate cancer cell lines, PC3 and LNCaP. We adopted a clonogenic assay to validate RDE and the radiosensitizing effect induced by MHT. The data on survival fractions were analyzed using both the linear-quadradic model and Arrhenius model to estimate the biological parameters describing RDE and radiosensitizing effect of MHRT for both cell lines through maximum likelihood estimation. Based on these parameters, a new survival fraction model was suggested for EQD estimation of MHRT. RESULTS: The newly designed model describing the MHRT effect, effectively captures the variations in thermal and radiation dose for both cell lines (R2 > 0.95), and its suitability was confirmed through the normality test of residuals. This model appropriately describes the survival fractions up to 10 Gy for PC3 cells and 8 Gy for LNCaP cells under RT-only conditions. Furthermore, using the newly defined parameter r, the RDE effect was calculated as 29% in PC3 cells and 23% in LNCaP cells. EQDMHRT calculated through this model was 9.47 Gy for PC3 and 4.71 Gy for LNCaP when given 2 Gy and MHT for 30 min. Compared to EQDHTRT, EQDMHRT showed a 26% increase for PC3 and a 20% increase for LNCaP. CONCLUSIONS: The proposed model effectively describes the changes of the survival fraction induced by MHRT in both cell lines and adequately represents actual data values through residual analysis. Newly suggested parameter r for RDE effect shows potential for quantitative comparisons between HTRT and MHRT, and optimizing therapeutic outcomes in MHRT for prostate cancer.

Radiation dose estimation with multiple artificial neural networks in dicentric chromosome assay.

PURPOSE: The dicentric chromosome assay (DCA), often referred to as the 'gold standard' in radiation dose estimation, exhibits significant challenges as a consequence of its labor-intensive nature and dependency on expert knowledge. Existing automated technologies face limitations in accurately identifying dicentric chromosomes (DCs), resulting in decreased precision for radiation dose estimation. Furthermore, in the process of identifying DCs through automatic or semi-automatic methods, the resulting distribution could demonstrate under-dispersion or over-dispersion, which results in significant deviations from the Poisson distribution. In response to these issues, we developed an algorithm that employs deep learning to automatically identify chromosomes and perform fully automatic and accurate estimation of diverse radiation doses, adhering to a Poisson distribution. MATERIALS AND METHODS: The dataset utilized for the dose estimation algorithm was generated from 30 healthy donors, with samples created across seven doses, ranging from 0 to 4 Gy. The procedure encompasses several steps: extracting images for dose estimation, counting chromosomes, and detecting DC and fragments. To accomplish these tasks, we utilize a diverse array of artificial neural networks (ANNs). The identification of DCs was accomplished using a detection mechanism that integrates both deep learning-based object detection and classification methods. Based on these detection results, dose-response curves were constructed. A dose estimation was carried out by combining a regression-based ANN with the Monte-Carlo method. RESULTS: In the process of extracting images for dose analysis and identifying DCs, an under-dispersion tendency was observed. To rectify the discrepancy, classification ANN was employed to identify the results of DC detection. This approach led to satisfaction of Poisson distribution criteria by 32 out of the initial pool of 35 data points. In the subsequent stage, dose-response curves were constructed using data from 25 donors. Data provided by the remaining five donors served in performing dose estimations, which were subsequently calibrated by incorporating a regression-based ANN. Of the 23 points, 22 fell within their respective confidence intervals at p < .05 (95%), except for those associated with doses at levels below 0.5 Gy, where accurate calculation was obstructed by numerical issues. The accuracy of dose estimation has been improved for all radiation levels, with the exception of 1 Gy. CONCLUSIONS: This study successfully demonstrates a high-precision dose estimation method across a general range up to 4 Gy through fully automated detection of DCs, adhering strictly to Poisson distribution. Incorporating multiple ANNs confirms the ability to perform fully automated radiation dose estimation. This approach is particularly advantageous in scenarios such as large-scale radiological incidents, improving operational efficiency and speeding up procedures while maintaining consistency in assessments. Moreover, it reduces potential human error and enhances the reliability of results.

Proton spot dose estimation based on positron activity distributions with neural network.

BACKGROUND: Positron emission tomography (PET) has been investigated for its ability to reconstruct proton-induced positron activity distributions in proton therapy. This technique holds potential for range verification in clinical practice. Recently, deep learning-based dose estimation from positron activity distributions shows promise for in vivo proton dose monitoring and guided proton therapy. PURPOSE: This study evaluates the effectiveness of three classical neural network models, recurrent neural network (RNN), U-Net, and Transformer, for proton dose estimating. It also investigates the characteristics of these models, providing valuable insights for selecting the appropriate model in clinical practice. METHODS: Proton dose calculations for spot beams were simulated using Geant4. Computed tomography (CT) images from four head cases were utilized, with three for training neural networks and the remaining one for testing. The neural networks were trained with one-dimensional (1D) positron activity distributions as inputs and generated 1D dose distributions as outputs. The impact of the number of training samples on the networks was examined, and their dose prediction performance in both homogeneous brain and heterogeneous nasopharynx sites was evaluated. Additionally, the effect of positron activity distribution uncertainty on dose prediction performance was investigated. To quantitatively evaluate the models, mean relative error (MRE) and absolute range error (ARE) were used as evaluation metrics. RESULTS: The U-Net exhibited a notable advantage in range verification with a smaller number of training samples, achieving approximately 75% of AREs below 0.5 mm using only 500 training samples. The networks performed better in the homogeneous brain site compared to the heterogeneous nasopharyngeal site. In the homogeneous brain site, all networks exhibited small AREs, with approximately 90% of the AREs below 0.5 mm. The Transformer exhibited the best overall dose distribution prediction, with approximately 92% of MREs below 3%. In the heterogeneous nasopharyngeal site, all networks demonstrated acceptable AREs, with approximately 88% of AREs below 3 mm. The Transformer maintained the best overall dose distribution prediction, with approximately 85% of MREs below 5%. The performance of all three networks in dose prediction declined as the uncertainty of positron activity distribution increased, and the Transformer consistently outperformed the other networks in all cases. CONCLUSIONS: Both the U-Net and the Transformer have certain advantages in the proton dose estimation task. The U-Net proves well suited for range verification with a small training sample size, while the Transformer outperforms others at dose-guided proton therapy.

Accurate gamma-ray dose measurement up to 10 MeV by glass dosimeter with a sensitivity control filter for BNCT.

Glass dosimeters are very useful and convenient detection elements in radiation dosimetry. In this study, this glass dosimeter was applied to a BNCT treatment field. Boron Neutron Capture Therapy (BNCT) is a next-generation radiation therapy that can selectively kill only cancer cells. In the BNCT treatment field, both neutrons and secondary gamma-rays are generated. In other words, it is a mixed radiation field of neutrons and gamma-rays. We thus proposed a novel method to measure only gamma-ray dose in the mixed field using two RPLGD (Radiophoto-luminescence Glass Dosimeter) and two sensitivity control filters in order to control the dose response of the filtered RPLGD to be proportional to the air kerma coefficients, even if the gamma-ray energy spectrum is unknown. As the filter material iron was selected, and it was finally confirmed that reproduction of the air kerma coefficients was excellent within an error of 5.3% in the entire energy range up to 10 MeV. In order to validate this method, irradiation experiments were carried out using standard gamma-ray sources. As the result, the measured doses were in acceptably good agreement with the theoretical calculation results by PHITS. In the irradiation experiment with a volume source in a nuclear fuel storage room, the measured dose rates showed larger compared with survey meter values. In conclusion, the results of the standard sources showed the feasibility of this method, however for the volume source the dependence of the gamma-ray incident angle on the dosimeter was found to be not neglected. In the next step, it will be necessary to design a thinner filter in order to suppress the effect of the incident angle.

Integrating evolutionarily conserved mechanism of response to radiation for exploring novel Caenorhabditis elegans radiation-responsive genes for estimation of radiation dose associated with spaceflight.

During space exploration, space radiation is widely recognized as an inescapable perilous stressor, owing to its capacity to induce genomic DNA damage and escalate the likelihood of detrimental health outcomes. Rapid and reliable estimation of space radiation dose holds paramount significance in accurately assessing the health risks associated with spaceflight. However, the identification of space radiation-responsive genes, with their potential to serve as early indicators for diagnosing radiation dose associated with spaceflight, continues to pose a significant challenge. In this study, based on the evolutionarily conserved mechanism of radiation response, an in silico analysis method of homologous comparison was performed to identify the Caenorhabditis elegans orthologues of human radiation-responsive genes with possible roles in the major processes of response to radiation, and thereby to explore the potential C. elegans radiation-responsive genes for evaluating the levels of space radiation exposure. The results showed that there were 60 known C. elegans radiation-responsive genes and 211 C. elegans orthologues of human radiation-responsive genes implicated in the major processes of response to radiation. Through an investigation of all available transcriptomic datasets obtained from space-flown C. elegans, it was observed that the expression levels of the majority of these putative C. elegans radiation-responsive genes identified in this study were notably changed across various spaceflight conditions. Furthermore, this study indicated that within the identified genes, 19 known C. elegans radiation-responsive genes and 40 newly identified C. elegans orthologues of human radiation-responsive genes exhibited a remarkable positive correlation with the duration of spaceflight. Moreover, a noteworthy presence of substantial multi-collinearity among the majority of these identified genes was observed. This observation lends support to the possibility of treating each identified gene as an independent indicator of radiation dose in space. Ultimately, a subset of 15 potential radiation-responsive genes was identified, presenting the most promising indicators for estimation of radiation dose associated with spaceflight in C. elegans.

Application of Monte Carlo simulation in radiation dose estimation and optimization for diagnostic radiology / 中华放射医学与防护杂志

The increasing frequency of radiographic diagnostic imaging and the cumulative dose to the public from radiation has raised widespread concerns. However, accurate measurement of the radiation dose received by the human body is difficult to achieve. Monte Carlo simulation, as a numerical computational method guided by probability statistics theory, has been applied to various dose assessments, imaging optimizations, and radiation protection in radiographic diagnostic imaging. We provide a comprehensive review of the principles of the Monte Carlo method, the modelling process of Monte Carlo simulation and the progress of its application to diagnostic radiological dose estimation.

Analysis of intercomparison results of national biological dose estimation capability in 2022 / 中华放射医学与防护杂志

Objective:To improve the ability of radiation health technical institutions for biological dose estimation.Methods:A total of 144 institutions nationwide, including the CDC, prevention and treatment center for occupational disease, colleges and universities, scientific research institutes, nuclear industry systems, and medical and physical examination institutions, were organized to carry out the intercomparison of national biological dose estimation capabilities in 2022. The institutions participating in the comparison were divided into two types of A and B, through the identification of chromosome aberrations, to estimate the irradiation dose (A) or chromosome aberration rate (B). The results were summarized and compared, and the main problems were analyzed and discussed.Results:There were 60 institutions in type A, 52 qualified institutions (including 12 excellent institutions) and 8 unqualified institutions, with a pass rate of 86.7% (20.0% excellent) and a failure rate of 13.3%. There were 84 institutions participating in the biological dose estimation comparison of type B, with 48 qualified institutions, and 36 unqualified institutions, the qualified rate was 57.1%, and the unqualified rate was 42.9%.Conclusions:Most of the institutions participating in type A comparison have the ability to estimate biological dose, and more than half of the institutions participating in type B comparison have the ability to analyze chromosome aberration. The overall ability of institutions participating in type A comparison is higher than in type B.

Establishment and validation of a dose-response curve for semi-automatic analysis of dicentric chromosomes / 中国职业医学

ObjectiveTo establish a dose-effect curve for semi-automatic analysis of dicentric chromosomes(DC) based on an automatic chromosome analysis system. Methods A total of three healthy volunteers were recruited as the study subjects, and their peripheral blood was collected and stimulated by X-ray at doses of 0.00, 0.10, 0.25, 0.50, 0.75, 1.00, 2.00, 3.00, 4.00, and 5.00 Gy, with the absorbed dose rate of 1.0 Gy/min. Images of DC in the mid-stage of cell division were collected using a high-throughput automatic chromosome analysis system. The DCScore software was used to automatically analyze DC aberrations, and a dose-effect curve for semi-automatic analysis of DC was fitted after manual confirmation. The fitted dose-effect curve for semi-automatic analysis of DC was validated for accuracy using three proficiency test samples from the national quality assessment of biological dose. Results The incidence of DC increased with increasing irradiation doses in the range of 0.00-5.00 Gy (P<0.01). The dose-effect curve for the fitted semi-automatic analysis of DC was ŷ =0.000 8 (±0.000 2) +0.009 2(±0.000 9) D+0.014 2(±0.000 4) D2 (R2= 0.999 8). The relative deviation between the estimated dose and the actual dose of the three test samples was about 20.00%, indicating curve applicability for biological dose estimation. Moreover, excluding the time spent on manual analysis, the semi-automatic analysis method increased the analysis efficiency by 26.0 times. Conclusion The semi-automatic analysis dose-effect curve for DC stimulated by X-ray is constructed for biological dose estimation, which can reduce the manual analysis time, and holds great potential for application in nuclear emergency response to large-scale radiation accidents.

Establishing a three-dimensional model for estimating partial-body irradiation doses based on γ-H2AX foci detection / 中华放射医学与防护杂志

Objective:To construct a three-dimensional time-dose-response model for dose estimation and validate its feasibility.Methods:Based on a random number table, mice were divided into 0, 2, 4, 6, and 8 Gy groups for whole-body X-ray irradiation, with each group consisting of three mice. Hair follicle cells of whiskers were sampled at 1, 6, and 24 h after the irradiation. After immunofluorescence staining, the numbers of γ-H2AX foci at different time points from 1 to 24 h post-irradiation were observed using a confocal laser scanning microscope. The average numbers of γ-H2AX foci observed were corrected using the Dolphin’s model, followed by the fitting of dose-response curves. Using the R software, the equations and surfaces of the three-dimensional model for partial-body irradiation were established using the irradiation doses, post-irradiation time, and the corrected average numbers of γ-H2AX foci.Results:The average number of γ-H2AX foci increased with dose at fixed time points 1, 6, and 24 h but decreased with irradiation time at fixed doses 2, 4, 6, and 8 Gy. The dose-response curve equations of partial-body irradiation were fitted as follows: YF = 2.853+ 3.775 D, R2= 0.928, at 1 h after the irradiation; YF = 0.144+ 2.775 D, R2= 0.903, at 6 h after the irradiation; YF = 0.066+ 2.472 D, R2= 0.85, at 24 h after the irradiation. The three-dimensional model equation fitted was YF = 6.837 t-1.728+ 3.113 t-0.071D, R2=0.897. Substituting different post-irradiation time points into the three-dimensional surface model appeared as a two-dimensional linear model. By substituting the number of γ-H2AX foci and irradiation time into the linear and the three-dimensional models, both models yielded relative deviations between the estimated and actual radiation doses of 30% or less. Conclusions:The three-dimensional time-dose-response model, established by using the number of γ-H2AX foci to estimate partial-body irradiation doses, can be preliminarily applied for dose estimation at all time points 1-24 h after irradiation.

Estimation of the effective radiation dose for tunnel construction workers / 中国职业医学

Objective To analyze and set up the effective dose of different ionizing radiation for tunnel construction workers. Methods A total of five tunnels constructed using drilling and blasting methods were selected as the research subjects using the convenient sampling method. The workplace γ radiation effective dose, radon concentrations, and radioactive activity concentrations were detected, and on-site surveys were conducted to estimate the internal and external irradiation doses and total effective doses for workers in different work sites. Results Radiological hazards in tunnels constructed using drilling and blasting methods included radon and its progeny, γ radiation, radioactive dust (uranium-238, radium-226, thorium-232, and potassium-40) and others. The average total effective dose of ionizing radiation exposure for tunnel construction workers was (6.730 1±1.541 1) mSv. The average dose of radon and its progeny was (6.163 0±1.512 8) mSv, radioactive dust was (0.014 6±0.009 1) mSv, γ radiation was (0.552 6±0.138 7) mSv. The dose of radioactive dust of radon and its progeny was 0.24%. Radon and its progeny contributed more to the radioactive dose than radioactive dust and γ radiation (all P<0.05). Among all the radioactive dusts, the dose contribution ranked from highest to lowest was thorium-232, uranium-238, and radium-226. Conclusion For tunnel construction workers, the largest contribution to the effective dose of ionizing radiation exposure is from radon and its progeny for internal irradiation, followed by γ radiation for external irradiation. The contribution of radioactive dust to internal irradiation dose can be considered negligible.

Dose estimation in etiology of occupational radiogenic neoplasms: A case analysis / 中国辐射卫生

Objective To analyze the problems and solutions in the diagnosis of a patient with occupational radiogenic neoplasms. Methods The dose conversion method was selected in dose estimation. Personal dose equivalent, skin absorbed dose, and reported detection data were converted into red bone marrow absorbed dose. The upper 95% confidence limit of the probability of causation (PC 95%) was calculated. Results The PC 95% of cancer due to radiation in the worker was 66.38%, which suggested occupational radiogenic neoplasms. Personal dose data were missing in dose estimation. The current dose estimation standard lacked bedside radiography and CT operation type, and the dose conversion formula was not perfect. Conclusion In the judgment of occupational radiogenic neoplasms, the estimated dose showed uncertainty. There is an urgent need to formulate and promulgate dose estimation standards that are operational and in line with the current development of radiological diagnosis and treatment technology and equipment.

An analysis of the investigation results of radionuclide content in food in Chongqing, China / 中国辐射卫生

Objective To investigate the radionuclide content in food in Chongqing, China by conducting a survey on the radioactivity in food. Methods A total of 114 samples of vegetables, grain, milk powder, and tea were collected in Chongqing. The samples were dried, pulverized into powder, added into Marinelli beakers, and then measured for radionuclides using a high-purity germanium gamma spectrometer (GEM40P4-765). Results The mean activity concentrations of natural radionuclides 238U, 232Th, 226Ra, and 40K in food in Chongqing were (0.396 ± 0.510), (0.199 ± 0.296), (0.140 ± 0.209), and (119.250 ± 105.470) Bq/kg, respectively. The contents of radionuclides in different foods were significantly different (P < 0.05). The mean activity concentration of the artificial radionuclide 137Cs was (0.091 ± 0.308) Bq/kg, and the mean activity concentration of 90Sr measured in nine tea samples was (1.243 ± 0.860) Bq/kg. Conclusion The contents of radionuclides in food in Chongqing are lower than the national standard limits, but the safety of radioactivity in food still needs to be taken seriously, and long-term surveillance of radioactivity in food is needed.

Research progress of imaging flow cytometry in automatic analysis of radiation biodosimetric indicators / 中国辐射卫生

@#A large number of people would be exposed to irradiation in large-scale nuclear and radiation accidents or nuclear terrorist attacks. Therefore, it is urgent to establish rapid and high-throughput biodosimetry for in triage, providing a basis for emergency management. Imaging flow cytometry (IFC) possesses the high through put advantages of traditional flow cytometry and the sensitivity and specificity of microscope, and has a good application prospect in the research and development of rapid, automated, and high-throughput biological dose estimation technology. This article reviews the application progress of IFC in biodosimetry, and provides a reference for the development of biological dose estimation and detection equipment for large-scale nuclear and radiation accidents.

Radiation field reconstruction and hand dose estimation for operators injured by a X-ray device radiological accident / 中华放射医学与防护杂志

Objective:To evaluate the radiation dose to the injured persons in a radiological accident, provide the guidance on the diagnosis and treatment of radiation injury, and provide the basis for determination of the level of radiological accident.Method:Firstly, the air-absorbed dose rates at 206 locations surrounding a X-ray device were measured by using LiF (Mg, Cu, P) thermoluminescence detectors and self-made radiation field measuring frames. Secondly, the spatial distribution of radiation level was obtained by fitting the inverse square law between absorbed dose rate and distance, which is used as the basis of dose estimation. Finally, based on the actual working conditions of injured operators, a parameter calculation method was proposed for estimating hand skin absorbed dose.Results:The air-absorbed dose rate surrounding X-ray beam outlet was higher than 1.0 mGy/h. The maximum air-absorbed dose rate value in the space of within 200 cm outside X-ray beam outlet was 262 μGy/h and the minimum value was 2.1 μGy/h, 2 orders of magnitude higher than environmental background level. During normal operation, the total absorbed doses to the hand skin of two injured female operators were 36.9 and 16.9 Gy, respectively. During extreme operation, the hand skin-received total absorbed doses to the two operators were 85.2 and 38.9 Gy, respectively. Under the occupational health standard GBZ 106-2020, the two persons had acute radiation skin injury of grade Ⅲ or Ⅳ on their hands.Conclusions:The results of hand skin exposure doses provide effective support for diagnosis and treatment of radiation injuries and for the determination of radiological accident level. The method used in radiation field reconstruction and dose estimation mentioned in this study can provide reference for the treatment in the similar radiological accident.

Research progress on occupational hazards of cosmic radiation for aircrew / 环境与职业医学

According to the data released by the Civil Aviation Administration of China in 2020, there are more than 60000 pilots and more than 100000 flight attendants in China working with certificates in various airlines. The health of these aircrew is the basis for maintaining and continuing the smooth development of civil aviation. Aircrew are exposed to cosmic radiation at high altitudes. However, because the types of cosmic radiation are complex, changeable, and difficult to measure accurately, there is no definite conclusion as to whether it has any effect on the health of aircrew. This paper introduced the impacts of cosmic radiation on aircrew, reviewed the estimation of cosmic radiation dose at home and abroad, and summarized the cosmic radiation dose measurement methods and their limitations. It also pointed out the shortcomings of existing occupational health management of aircrew and put forward new suggestions on strengthening the health management of radiation hazards for aircrew.

Radiation effects on residents caused by comprehensive utilization of slag in building materials / 中国辐射卫生

Objective This study intends to analyze the radioactivity level of slag and its building materials, estimate the effective dose of the residents caused by the comprehensive utilization of slag in building materials, and provide basis for rational utilization of slag. Methods Data of slag production and its comprehensive utilization in building materials, radioactive level investigation and detection of slag and building materials in different periods and regions were collected from 2005 to 2016. Using the room model of concrete structure and the model of calculating equilibrium equivalent radon concentration with the specific activity of 226Ra in indoor building materials, the external and internal radiation doses of residents caused by comprehensive utilization of slag for building materials were estimated respectively, and then the annual additional effective dose and collective dose of residents were estimated. Results The contents of 226Ra and 232Th in the slag were relatively high, while the contents of 40K were relatively low. The radionuclide content in slag cement decreased significantly. The annual additional effective doses of slag used in concrete and cement mixture relative to ordinary cement were 0.40 mSv·a−1 and 0.20 mSv·a−1 respectively. The annual additional collective dose and 50-year collective dose caused by slag used in building materials were 3.87 × 103～1.84 × 104 man·Sv and 1.94 × 105～9.20 × 105 man·Sv respectively. Conclusion The comprehensive utilization of slag in building materials increases the additional effective dose of residents, so the use of some slag in building materials needs to be paid more attention to. In addition, the influence of comprehensive utilization of slag in building materials, such as the way, the amount of slag and the amount of building materials, on the annual additional effective dose of residents caused should also be paid attention to.

Ongoing research on monitoring of internal exposure of nuclear medical staff / 中华放射医学与防护杂志

With the wide application of nuclear medicine and the increase in the number of related staff, the potential occupational health problems should receive enough attention. At present, the personal dose monitoring of most radiation workers in nuclear medicine is mainly based on the information on external exposure provided by thermoluminescence dosimeters whereas the routine internal exposure monitoring has not fully been carried out, thus resulting in underestimating their annual effective dose. Comprehensive personal dose monitoring is not only an important part of occupational health monitoring, but also a crucial means of occupational health management. In this paper, the characteristics of internal exposure in nuclear medicine were analyzed, the monitoring techniques and dose estimating method were introduced, and several commonly used softwares were listed, so as to comprehensively and objectively learn about the current internal radiation exposure of nuclear medicine workers, and to provide reference for health administration departments to formulate regulatory policies and protection requirements.

Physical dose estimation for an accidental exposed person in industrial γ-ray flaw detection / 中华放射医学与防护杂志

Objective:To estimate the physical dose of an over exposed person working for industrial radiography.Methods:The main exposure parameters were obtained. The exposure duration was 8 min. The exposure pattern was external exposure by isotropic point radioactive source. The radioactive activity was 2.183 TBq. In the present calculation, the Chinese reference adult voxel phantom was used, and the Monte Carlo simulation was performed using the program based on the secondary development of Geant4 to obtain the absorbed dose of each part of the victim.Results:The dose distribution in the victim′s hands was obtained. The doses to most areas of the palm were 2-10 Gy, and the doses to the fingers were 10-20 Gy. The equivalent doses to 23 tissues or organs of the exposed person were estimated to be in the range of 0.012-0.207 Gy.Conclusions:The physical dose estimation method could evaluate rapidly the local dose distribution of the victim′s key exposed body parts, and thus provide an important reference for medical treatment.

Investigation and analysis of an extensive skin injury to the back caused by accidental irradiation in interventional procedure / 中华放射医学与防护杂志

Objective:To carry out investigation and analysis of an extensive skin radiation injury to the back accidentally caused by interventional procedure and to explore the problems faced in the event with emphasis on avoiding the reoccurance of similar events in the future.Methods:The data were collected by consulting the patient′s detailed medical history, collecting and analyzing clinical diagnosis and treatment data, tracking and observing their clinical manifestations and signs. The patient′s peripheral blood samples were also collected, together with the biological dose estimated and the equipment data collected on the site of the interventional treatment hospital.Results:The whole body dose to the patient was estimated to be 0.95 Gy. The typical values of kerma rate of radiation incident on the body surface due to fluoroscopic procedures were 373.5 mGy/min in subtraction modality and 47.8 mGy/min in fluoroscopy modality, respectively. The annual effective dose to the interventional radiologist was 20.51 mSv due to his operation in long-time radiation exposure conditions, higher than 3.09 mSv for other interventional radiologists with similar workload in the same department. The whole body and local clinical manifestations of the patients were in line with radiation injury. No clear diagnosis has been obtained in several hospitals, nor can obvious treatment outcomes be obsevered.Conclusion:Combined with the biological dose estimation result and clinical manifestations, the case was diagnosed as degree Ⅳ skin radiation injury. Radiation injury is closely related to whether the operation is conducted according to the standard and the output dose of X-ray machine. Non-specialized hospitals should strengthen clinical diagnosis and treatment of radiation injury.