Objective To investigate the role of the O-6-methylguanine-DNA methyltransferase (MGMT) gene-3′ untranslated region (UTR) microRNA-associated single nucleotide polymorphism (miRSNP) (rs7896488 G>A) in affecting miR-4297-targeted modulation of MGMT in senescence of lung cells with polymorphic genotypes induced by fractionated low dose ionizing radiation (LDIR). Methods i) MiRSNPs were predicted and screened using bioinformatics, and DNA from two types of lung cells, A549 cells and human bronchial epithelioid cells (HBE cells), was extracted for target gene sequencing. After co-transfection of pGL3c-MGMT-3′UTR-rs7896488 G>A reporter gene recombinant plasmid, pRL-TK Vector with micrON mimic NC #22 or micrON hsa-miR-4297 mimic (set up as the mimic NC group and the miR-4297 mimic group) in these two types of lung cells, dual luciferase reporter gene assay was performed. The relative expression of MGMT mRNA was detected by real-time fluorescence quantitative polymerase chain reaction, and the relative expression of MGMT protein was detected by Western blotting. ii) These two types of lung cells were randomly divided into the control group and irradiation group, which received either 0 or 100 mGy X-rays irradiation seven times. After irradiation, the cells were transfected with either micrON mimic NC #22 or micrON hsa-miR-4297 mimic, resulting in mimic NC + control group, miR-4297 mimic + control group, mimic NC + irradiation group, and miR-4297 mimic + irradiation group. Cells were collected for senescence-associated-β-galactosidase (SA-β-Gal) staining, and the relative expression of matrix metalloproteinase-9 (MMP-9) and chemokine (C-X-C motif) ligand-1 (CXCL-1) proteins was detected via Western blotting. Results i) The rs7896488 G>A was the miRSNP located in the conserved binding region targeted by miR-4297 in the MGMT gene 3′UTR. A549 cells were the rs7896488 GG wild-type homozygous genotype, while HBE cells were the rs7896488 GA heterozygous mutant genotype. In the miR-4297 mimic group, A549 and HBE cells carrying the rs7896488 G allele showed significantly lower dual-luciferase activity compared with that in the mimic NC group (both P<0.01). However, there was no significant difference in dual-luciferase activity between the two groups in both A549 and HBE cells carrying the rs7896488 A allele (both P>0.05). The relative expression levels of MGMT mRNA and MGMT protein of A549 cells in the miR-4297 mimic group were lower than those in the mimic NC group (both P<0.05). However, there was no significant difference in MGMT mRNA and MGMT protein of HBE cells between these two groups (both P>0.05). ii) The relative activity of SA-β-Gal and the relative expression of MMP-9 and CXCL-1 proteins of A549 cells in the miR-4297 mimic+irradiation group were higher than those in the mimic NC + control group, the miR-4297 mimic + control group, and the mimic NC + irradiation group (all P<0.05). The relative activity of SA-β-Gal and the relative expression of MMP-9 and CXCL-1 proteins of HBE cells in the miR-4297 mimic + irradiation group were higher than those in the mimic NC + control group and the miR-4297 mimic + control group (all P<0.05), while there was no significant difference compared with those in the mimic NC + irradiation group (all P>0.05). Conclusion MGMT-3′UTR-miRSNP rs7896488 G>A plays a role in LDIR-induced senescence of lung cells with different polymorphic genotypes by affecting miR-4297-targeted regulation of MGMT.

Objective To assess the current status of occupational radiation hazards in animal diagnosis and treatment institutions in Foshan City. Methods A total of 214 animal diagnosis and treatment institutions in Foshan City in 2024 were selected as the study subjects using the judgment sampling method. The radiation protection management status was investigated. Results A total of 178 out of the 214 animal diagnosis and treatment institutions were equipped with radiation diagnostic equipment in Foshan City. Among these 178 institutions, 98 (accounting for 55.1%) obtained permits from the ecology and environmental department, 21 (accounting for 11.8%) completed occupational hazard project declarations, 53 (accounting for 29.8%) conducted workplace radiation level monitoring, 132 (accounting for 74.2%) were equipped with radiation protection equipment, 40 (accounting for 22.5%) conducted occupational health examinations for the radiation staff, 39 (accounting for 21.9%) provided radiation protection knowledge training for the radiation staff, and 52 (accounting for 29.2%) performed personal radiation dose monitoring. However, none of the institutions implemented the “Three Simultaneities (design, construct, put into operation and use simultaneously with the main body of the construction project)” system for occupational disease prevention facilities in construction projects. Conclusion sAnimal diagnostic and treatment institutions in Foshan City have low levels of radiation protection management and inadequate occupational health monitoring. The radiation staff has low awareness of radiation protection, Relevant department should strengthen supervision and management, organize radiation protection knowledge training, and standardize occupational health management to effectively safeguard workers' health rights.

Objective To understand the situation of dental cone beam computed tomography (CBCT) quality control testing phantoms in radiation health technical service institutions in Guangdong province, analyze the differences among different phantoms, and provide a reference for dental CBCT quality control testing. Methods The testing phantoms of 49 radiation health technical service institutions were used as the research objects. The designated CBCT equipment was used for scanning and imaging. The Z-score method was used to evaluate the high-contrast resolution, low-contrast resolution, and distance measurement deviation of each phantom. Results The satisfaction rates of various items for the phantoms in 49 institutions ranged from 85.7% to 100%. The distance measurement deviations of four institutions were “suspicious”, and the high-contrast resolution of four institutions and the distance measurement deviation of one institution were “unsatisfactory”. Conclusion The overall performance of dental CBCT quality control testing phantoms in radiological health technical service institutions in Guangdong province is satisfactory. However, there are still some phantoms with poor results in items such as distance measurement deviation and high-contrast resolution. The structural design, material selection, and manufacturing process of the phantom may all affect the results of quality control testing. Therefore, appropriate phantoms, optimized exposure conditions, and suitable reconstruction algorithms should be used in CBCT quality control testing to ensure accurate and reliable measurements.

Objective To investigate the effects of fractionated low-dose ionizing radiation (LDIR) on the ferroptosis in human bronchial epithelial (HBE) cells as well as the associated differentially expressed genes (DEGs), biological processes, and signaling pathways. Methods HBE cells were exposed to different single doses of X-ray irradiation (0, 25, 50, 75, and 100 mGy) for 24, 48, and 72 h, respectively. The change in cell viability was detected by MTT assay. Cells were irradiated with 0, 25, 50, and 100 mGy X-rays 5 times, with 48 h between each irradiation and a dose rate of 50 mGy/min. Cells were harvested 24 h after irradiation for the measurement of the expression of ferroptosis-related genes SLC7A11 and GPX4 at the mRNA and protein levels, cellular iron content, and the expression of FTH1 and FTL mRNAs. High-throughput sequencing was used to screen for the DEGs in each dose group, followed by Gene Ontology-Biological Process (GO-BP) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and Gene Set Enrichment Analysis (GSEA). Results Compared with the control group, single-dose LDIR significantly increased cell proliferation at 75 mGy after 24 h (P < 0.05), at 50, 75, and 100 mGy after 48 h (P < 0.05), and at 75 and 100 mGy after 72 h (P < 0.05). Compared with the control group, at the end of the fifth fractionated LDIR, SLC7A11 and GPX4 mRNAs decreased at all doses (P < 0.05), SLC7A11 protein decreased at all doses, GPX4 protein decreased at 25 and 100 mGy, iron content increased at all doses, and FTH1 and FTL mRNAs decreased at all doses (P< 0.05). Sequencing analysis identified 248, 30, and 291 DEGs and 10, 2, and 9 ferroptosis-associated genes at the three doses compared to the control. Gene Ontology-Biological Process analysis showed that DEGs were mainly enriched in biological processes such as response to lipids, cell death, and response to unfolded proteins. Kyoto Encyclopedia of Genes and Genomes analysis showed that DEGs were mainly enriched in the JAK-STAT signaling pathway, lipids and atherosclerosis, ferroptosis, protein processing in the endoplasmic reticulum, and FoxO signaling pathway. Gene set enrichment analysis showed that DEGs were mainly enriched in ferroptosis, fatty acid degradation, and glutathione metabolism. Conclusion Fractionated low-dose radiation induced ferroptosis in HBE cells, and DEGs were predominantly enriched in biological processes and signaling pathways related to inflammation, ferroptosis, and endoplasmic reticulum stress.

Objective To analyze bedside radiation dose rates for interventional surgery operators in Guangdong Province, examine dose distribution patterns, and identify potential weaknesses in radiation protection, and to provide guidance for optimizing radiation monitoring and protection measures. Methods A total of 209 digital subtraction angiography devices measured in Guangdong Province between 2017 and 2024 were used as the research objects. The first and second operator positions were set at 30 cm and 90 cm horizontally from the X-ray tube focal point, respectively. Monitoring points were set up at 155, 125, 105, 80, and 20 cm above the ground. Results The median bedside radiation dose rate for interventional surgery operators in Guangdong Province was 83.0 (3.9, 1044.0) μSv/h, indicating instances of exceeding standard limits. The overall dose rates under the old and new standards were 29.8 (3.9-346.5) μSv/h and 114.0 (4.0-1044.0) μSv/h respectively. Results for both standards showed a higher dose rate at the second than the first operator position. The dose rates at the heights of 105 cm (abdomen), 125 cm (chest), and 155 cm (head) were higher in the second operator position than in the first operator position. Additionally, 71.5% and 56.8% of the highest dose rate points under the new and old standards, respectively, were concentrated at 105 cm (abdomen), 125 cm (chest) and 155 cm (head) in the second operator position. Conclusion The principle of protection optimization should be followed, auxiliary protective facilities should be placed correctly, and attention should be paid to the protection of the second surgery operator position, especially above the abdomen. The dose rate results under the new standard were lower than those under the old standard, suggesting that the measurement method may overestimate radiation exposure at the secondary operator position.

Background In recent years, the increasingly widespread application of nuclear and medical radiation technologies has resulted in a large number of occupational populations exposed to low-dose ionizing radiation (LDIR). At present, there is no consistent conclusion on the effects of long-term exposure to LDIR on the metabolic health of the occupational population. Objective To explore the association between long-term exposure to LDIR and metabolic syndrome (MetS) among medical radiologists. Methods A cross-sectional study was conducted to enroll 6431 medical radiologists who ordered occupational health checkups from January 2022 to December 2023, and basic information such as demographic characteristics, occupational characteristics, lifestyles, and dietary habits was collected through questionnaires. Physical examinations were conducted using a standardized protocol. Individual dose equivalents of occupational external exposure were monitored by dosimeters worn by medical radiologists. Logistic regression model was used for identifying influencing factors of MetS and sensitivity analysis, and restricted cubic spline model was used to explore the dose-response relationship between cumulative effective dose and MetS. Two-stage linear regression was used to evaluate threshold effect of association between cumulative effective dose and MetS. Results The positive rate of MetS was 13.6% (877/6431) among the enrolled 6431 study participants. The logistic regression showed that gender, age, monthly income, body mass index (BMI), cumulative effective dose, and smoking were influencing factors for MetS. The risk of MetS was higher in males (OR=1.511, 95%CI: 1.209, 1.888); using the < 30 years old group as reference, the risk of MetS was higher in the 30-39 years old (OR=1.509, 95%CI: 1.095, 2.079), 40-49 years old (OR=2.214, 95%CI: 1.551, 3.161), and ≥50 years old (OR=3.480, 95%CI: 2.338, 5.181) groups; using the <10000 yuan group as reference, the risk of MetS was lower in the group with a monthly income of 10000-14999 yuan (OR=0.715, 95%CI: 0.582, 0.878); the risk of MetS was higher in the BMI ≥ 24 kg·m⁻² group (OR=7.548, 95%CI: 6.223, 9.156); using the < 0.76 mSv group as reference, the risk of MetS was higher in the cumulative effective dose of 0.76-2.73 mSv group (OR=1.270, 95%CI: 1.017, 1.586); the risk of MetS was higher in the smoking group (OR=1.734, 95%CI: 1.428, 2.107). The results of restricted cubic spline showed that the cumulative effective dose was nonlinearly correlated with MetS (P _{non-linearity}=0.028), with an inflection point of 1.25 mSv. The risk of developing MetS increased by 34.1% for each unit increase in cumulative effective dose up to 1.25 mSv, whereas above 1.25 mSv, the statistical association was not significant. The sensitivity analysis results showed that after excluding the self-reported hypertensive and diabetic patients, the cumulative effective dose 0.76-2.73 mSv group still had an increased risk of developing MetS compared with the < 0.76 mSv group (P < 0.05), and the results were robust. Conclusion Among medical radiologists, male, age, BMI, and smoking are positively correlated with MetS, and monthly income is negatively correlated with MetS; cumulative effective dose is non-linearly correlated with MetS among medical radiologists.

Objective To track and evaluate the implementation and application of the occupational health standard Radiation shielding requirements for radiotherapy room—Part 4: Radiotherapy room of ²⁵²Cf neutron afterloading (GBZ/T 201.4-2015) by radiation health technical service agencies, medical institutions, health supervision agencies, and radiotherapy facility design units, and to provide a scientific basis for the further revision and implementation of this standard. Methods Following the Guideline for health standards tracking evaluation (WS/T 536-2017) and the project implementation plan, relevant practitioners were randomly selected for a questionnaire survey. The survey primarily focused on their awareness, standard training, application, and revision suggestions of GBZ/T 201.4-2015. The results were summarized and analyzed. Results A total of 168 evaluation questionnaires were collected from relevant practitioners in 28 provinces. Only 31.6% of the respondents reported being “well familiar” or “ familiar” with the standard, 27.4% of the respondents believed that the standard was widely used, and 45.2% of the respondents believed that the standard could meet the needs of their work. Only 14.9% of the respondents had received relevant training on the standard, more than half of the respondents had not applied the standard within the past 10 years, and 45.2% of the respondents believed that the standard "needs to be revised". Conclusion Due to the small number of californium-252 neutron afterloading radiotherapy devices in operation on the market, the overall awareness of the standard is low, suggesting that relevant authorities need to strengthen training and publicity of the standard, and that certain sections of the standard need to be revised or merged.

Objective To investigate the induction of senescence in L02 hepatocytes by low-dose fractionated X-ray radiation and its effects on oxidative stress, oxidative damage, and nuclear factor-κB (NF-κB) pathway protein levels. Methods L02 cells were subjected to fractionated X-ray irradiation at doses of 0.1, 0.2, and 0.5 Gy per fraction for a total of six fractions. Assays were performed 24 hours after the final irradiation. Measurements included SA-β-gal staining, the mRNAs of senescence-related genes p53 and p21 and their encoded proteins, mRNAs of genes encoding senescence-associated secretory phenotype factors (IL-6, IL-8, GM-CSF, MMP-15), reactive oxygen species, oxidative and anti-oxidative markers (malondialdehyde, glutathione, superoxide dismutase), DNA oxidative damage markers (8-OHdG and γ-H2AX), and NF-κB pathway protein levels. Results Compared with the control group, at 24 hours after the end of six irradiations, the number of cells positive in SA-β-gal staining was significantly increased in all dose groups. The mRNA and protein levels of p21 and p53 were significantly elevated in the 0.2 Gy × 6 and 0.5 Gy × 6 groups (P < 0.05). The mRNA levels of genes encoding IL-6, GM-CSF, and MMP-15 were significantly increased in all dose groups (P < 0.05). The mRNA levels of the gene encoding IL-8 were significantly increased in the 0.2 Gy × 6 and 0.5 Gy × 6 groups (P < 0.05). The levels of reactive oxygen species, malondialdehyde, and glutathione were significantly increased in all dose groups (P < 0.01). The level of superoxide dismutase was significantly increased in the 0.5 Gy × 6 group (P < 0.01). The levels of 8-OHdG were significantly increased in all dose groups (P < 0.05). In both the 0.2 Gy × 6 and 0.5 Gy × 6 groups, the expression levels of γ-H2AX and p-NF-κB p65 were significantly increased (P < 0.05), and the levels of IκBα were significantly decreased (P < 0.05). Conclusion Low-dose fractionated X-ray radiation can induce senescence and cause alterations in oxidative stress, oxidative damage, and the levels of NF-κB pathway proteins in L02 hepatocytes.

Objective To explore the differentially expressed mRNAs and related biological processes and pathways in fractional low-dose ionizing radiation (LDIR)-induced senescence of normal human bronchial epithelial (HBE) cells by high-throughput mRNA sequencing and bioinformatics techniques. Methods Senescence-associated β-galactosidase staining and senescence-associated secretion phenotype gene mRNA and protein expression levels were measured at 24 and 48 h after irradiating HBE cells 7 times at doses of 0, 50, 100, and 200 mGy, respectively. The differentially expressed genes were screened by high-throughput sequencing for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Results The senescence-positive area of fractional low-dose irradiated HBE cells increased in a dose-dependent manner (P < 0.05). The mRNA levels and protein expression of transforming growth factor-β1(TGF-β1) and matrix metalloproteinase-9(MMP-9) genes were increased in the 100 mGy × 7 and 200 mGy × 7 groups at 24 and 48 h after the end of irradiation compared with the control group. High-throughput sequencing showed that there were 882, 475, and 1205 differentially expressed mRNAs in each dose group compared with the control group. GO analysis showed that the differentially expressed mRNAs in each dose group were mainly enriched in biological processes such as cell cycle regulation, regulation of nitrogen compound metabolic process, regulation of cell division and response to stimulus. KEGG analysis showed that the differentially expressed mRNAs were mainly enriched in the pathways of cell cycle, cell senescence, and ferroptosis. Conclusion Fractional LDIR induced senescence in HBE cells, and differentially expressed mRNA-associated biological processes and pathways in senescent cells are related to cell cycle and cell senescence.

Objective To investigate the mechanism of fractionated low-dose ionizing radiation (LDIR) in the induction of EA.hy926 cell senescence. Methods EA.hy926 cells were irradiated with X-ray at 0, 50, 100, and 200 mGy × 4, respectively, and cultured for 24, 48, and 72 h. Several indicators were measured, including the levels of cellular senescence-associated β-galactosidase (SA-β-gal) staining, mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A, reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and phosphorylated H2A histone family member X (γ-H2AX). Results After 4 fractionated LDIR, compared with the control group, the treatment groups showed increased nucleus area, blurred cell edge, and increased SA-β-gal positive area (P < 0.05) at 24, 48 and 72 h. After 4 fractionated LDIR, the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h (P < 0.05), and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). The fluorescence intensity of ROS increased in treatment groups at 24, 48, and 72 h after 4 fractionated LDIR (P < 0.05). After 4 fractionated LDIR, the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h (P < 0.05), and T-AOC level increased in all treatment groups at 48 and 72 h (P < 0.05). After 4 fractionated LDIR, γ-H2AX fluorescence intensity increased in all treatment groups at 24 h (P < 0.05), and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). Conclusion Fractionated LDIR can induce cellular senescence in EA.hy926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels, and the effects were relatively evident at 100 and 200 mGy.