A Survey of Mean Glandular Doses and Suggestions on National Diagnostic Reference Levels for Digital Mammography in China.

ABSTRACT: The primary purpose of this study was to report the mean glandular doses and to determine the national diagnostic reference levels for digital mammography based on data between 2016 and 2018 in China. The data from 19,076 mammograms (4,769 examinations) by random sampling from 118 digital mammography systems were compiled. Exposure factors included age, compressed breast thickness, kVp, mAs, target/filter combination, entrance surface air kerma, and mean glandular doses, which were retrospectively surveyed and recorded from the monitor. The national diagnostic reference levels (75th percentiles) in mean glandular dose were calculated across median value obtained for all included data and stratified to specific compressed breast thickness ranges. The patients' ages ranged from 22 to 88 y, with a median age of 45. The applied voltage and output medians were 28 kVp and 75.1 mAs for all exposure, respectively. The median CBTs were 45 mm and 48 mm for craniocaudal views and mediolateral oblique views, and the corresponding median mean glandular doses were 1.32 mGy and 1.40 mGy, respectively. The national diagnostic reference level at compressed breast thickness of 40-50 mm was 1.67 mGy for CC views and 1.71 mGy for MLO views. The median mean glandular doses varied significantly and increased with compressed breast thickness, demonstrating the necessity of establishing DRL according to breast thickness and optimizing the clinic's digital mammography practice in China.

Analysis of the Status of Radiation-generating Medical Devices in Mainland China.

ABSTRACT: The purpose of this paper is to describe the status of radiation-generating medical devices in mainland China. The number of diagnostic radiology and interventional radiology devices was collected from the national medical radiation protection monitoring information system, while the number of radiation therapy and nuclear medicine devices was from the published articles. Statistical analysis of the correlation was used to assess the relationship between the number of high technology medical devices and GDP per capita. A total of 143,064 radiation-generating medical devices were identified in mainland China, and diagnostic radiology devices accounted for 94% of those. The number of CTs was 14.84 per million, an increase by a factor of 1.45 compared to 2009. But the distribution of CTs was imbalanced among different areas: the highest number of CT per million population was 27.70 in Tibet, and the lowest was 8.55 per million population in Guangxi province. Statistical analysis of the correlation showed that the number of PET scanners per million population was positively correlated with GDP per capita, and similarly for medical accelerators. The number of mammographic devices per million population was much lower than that in other countries. The investment of radiation-generating medical devices in China was far from enough, especially for mammographic devices. More efforts should be taken to bring medical resources to regions with greater population areas in the future.Health Phys. 124(0):000-000; 2023.

ATM and TP53 polymorphisms modified susceptibility to radiation-induced lens opacity in natural high background radiation area, China.

Purpose: A population-based case-control study was conducted in Yangjiang and Enping areas in South China to assess whether the risk of lens opacity induced by natural high background radiation exposure is modulated by polymorphisms of ATM and TP53.Materials and methods: A total of 133 cases who were diagnosed with cortical and posterior subcapsular (PSC) opacity were recruited, and 419 healthy controls were selected through counter-matching in terms of radiation status. Genomic DNA from all the participants was genotyped with the Illumina platform for four single nucleotide polymorphisms of ATM (rs189037, rs373759, and rs4585) and TP53 (rs1042522). The cumulative lens dose received during the entire life was estimated based on annual indoor and outdoor radiation doses and gender- and age-specific occupancy factors. Non-conditional logistic regression was performed to calculate odds ratio (OR) and 95% confidence intervals (95% CI).Results:ATM rs189037 and TP53 rs1042522 were significantly related to cortical and PSC opacity. The risk of opacity was higher when individuals carried the A allele of ATM rs189037 and C allele of TP53 rs1042522, compared with GG genotype. ATM rs189037 A allele carriers (AG/AA) and TP53 rs1042522 C allele carriers (CG/CC) combined with a cumulative lens dose of 100 mGy or higher showed statistically significant opacity risks (OR = 5.51, 95% CI: 1.47-20.66; OR = 2.69, 95% CI: 1.10-6.60).Conclusion: The A allele of ATM rs189037 and C allele of TP53 rs1042522 increased the risk of lens opacity induced by radiation. These polymorphisms in ATM and TP53 might modify the risk of cortical and PSC opacity induced by chronic and prolonged low-dose radiation.

Assessment of Prospective Cancer Risks from Occupational Exposure to Ionizing Radiation—Introduction to IAEA TECDOC 1985 / 中国辐射卫生

Abstract@#As part of the human environment, ionizing radiation can produce adverse tissue reactions known as determinist- ic effects at sufficiently high exposure levels, and cause stochastic effects (cancer and genetic diseases), where single cells with mutations can trigger somatic or genetic effects, even at low exposure levels. Given the unfavorable health effects of ra- diation, a comprehensive technical report is warranted to address the measurement and control of radiation exposure levels. The Assessment of Prospective Cancer Risks from Occupational Exposure to Ionizing Radiation published by the Internation- al Atomic Energy Agency fills this gap. This paper outlines the methodology of prospective cancer risk assessment for work- ers occupationally exposed to radiation, which provides a flexible framework based on radiobiology, risk modeling, and epi- demiological data and a new tool for managing occupational radiation exposure and assessing potential risks from occupa- tional radiation exposure.

Lens opacity prevalence among the residents in high natural background radiation area in Yangjiang, China.

The aim of the study was to evaluate the risk and threshold doses of lens opacity among residents exposed to low-dose radiation. Residents aged ≥45 years were recruited from a high natural background radiation (HNBR) area in Yangjiang City and a control area selected from nearby Enping City. Lens opacities (LOPs) were classified according to the Lens Opacities Classification System (LOCS) III system. Face-to-face interviews were conducted to collect information on lifestyles, migration and medical history. Life-time cumulative doses were estimated using gender, age, occupancy factors and environmental radiation doses received indoors and outdoors. Logistic regression analyses were conducted to estimate the dose response and determine thresholds. In the HNBR area, among 479 study participants, 101 (21.1%), 245(51.1%) and 23 cases (4.8%), respectively, of cortical, nuclear and posterior subcapsular (PSC) LOPs were found. In the control area, those types of LOPs were identified among 58 cases (12.6%), 206 cases (51.2%) and 6 cases (1.3%) of 462 examinees, respectively. Cumulative eye lens dose was estimated to be 189.5 ± 36.5 mGy in the HNBR area. Logistic analyses gave odds ratios at 100 mGy of 1.26 [95% confidence interval (CI) 1.00-1.60], 0.81 (95% CI 0.64-1.01) and 1.73 (95% CI 1.05-2.85) for cortical, nuclear and PSC LOPs, respectively. For cortical LOPs, a logistic analysis with a threshold dose gave a threshold estimate of 140 mGy (90% CI 110-160 mGy). The results indicated that population exposed to life-time, low-dose-rate environmental radiation was at an elevated risk of cortical and PSC LOPs. A statistically significant threshold dose was obtained for cortical LOPs and no threshold dose for PSC LOPs.

Cardiac catheterization procedures in children with congenital heart disease: Increased chromosomal aberrations in peripheral lymphocytes.

Cardiac catheterization procedures are performed on about 20,000 children with congenital heart disease (CHD) annually in China. The procedure, which involves exposure to ionizing radiation, causes DNA damage and may lead to increased cancer risk. We have studied chromosomal aberrations (CA) in peripheral lymphocytes of CHD children. CA frequencies were assessed in an interventional group of 70 children who underwent cardiac catheterization and a control group of 51 children receiving open-heart surgery. Total CA and all chromosome-type aberrations were higher in the exposed children than in the control group. With respect to the type of septal defect, the translocation frequency was higher in patients with ventricular rather than atrial defects. Cardiac catheterization procedures increase CA frequencies and may also increase the risk of cancer.

Long-term immune effects of high-level natural radiation on Yangjiang inhabitants in China.

Purpose: Low dose radiation was found to perturb immune function or inflammatory reactions, which required further study. This study aimed to evaluate the health effects following long-term low dose radiation by detecting levels of peripheral blood lymphocyte subsets and serum cytokines of residents living in the Yangjiang High Background Radiation Area (HBRA). Materials and methods: Flow cytometry was used to detect peripheral blood T lymphocytes and its subsets (CD4+ T, CD8+ T lymphocyte) in 100 healthy female residents selected from HBRA and a Control Area (CA), respectively. Thirty cytokines or receptors and CRP levels were measured using antibody arrays in the 40 subjects described above. Subjects were chosen based on an age and BMI match between the two groups. Cytokine expression levels were then verified using ELISA methods. Result: In comparison to CA, CD8+ T lymphocyte numbers were significantly increased with cumulative dose following adjustment to age and BMI. Of the 30 selected targets, 22 indexes were measurable and inflammatory cytokines such as IFN-γ, IL-α, MCP-1, sIL-6R, EGFR, and CRP levels were observed to be significantly up-regulated with cumulative doses. ELISA results confirmed the cytokine array results and found CRP, MCP-1, and sIL-6R levels are linear with cumulative dose following adjustment to age and BMI. Conclusion: Immune function was found to be affected in humans exposed to long-term low dose radiation. Specifically, we observed an increase in CD8+T lymphocyte numbers and an up-regulation of inflammatory biomarkers, including IFN-γ, MCP-1, sIL-6R, EGFR, CRP.

Radiation dose in the thyroid and the thyroid cancer risk attributable to CT scans for pediatric patients in one general hospital of China.

OBJECTIVE: To quantify the radiation dose in the thyroid attributable to different CT scans and to estimate the thyroid cancer risk in pediatric patients. METHODS: The information about pediatric patients who underwent CT scans was abstracted from the radiology information system in one general hospital between 1 January 2012 and 31 December 2012. The radiation doses were calculated using the ImPACT Patient Dosimetry Calculator and the lifetime attributable risk (LAR) of thyroid cancer incidence was estimated based on the National Academies Biologic Effects of Ionizing Radiation VII model. RESULTS: The subjects comprised 922 children, 68% were males, and received 971 CT scans. The range of typical radiation dose to the thyroid was estimated to be 0.61-0.92 mGy for paranasal sinus CT scans, 1.10-2.45 mGy for head CT scans, and 2.63-5.76 mGy for chest CT scans. The LAR of thyroid cancer were as follows: for head CT, 1.1 per 100,000 for boys and 8.7 per 100,000 for girls; for paranasal sinus CT scans, 0.4 per 100,000 for boys and 2.7 per 100,000 for girls; for chest CT scans, 2.2 per 100,000 for boys and 14.2 per 100,000 for girls. The risk of thyroid cancer was substantially higher for girls than for the boys, and from chest CT scans was higher than that from head or paransal sinus CT scans. CONCLUSIONS: Chest CT scans caused higher thyroid dose and the LAR of thyroid cancer incidence, compared with paransal sinus or head CT scans. Therefore, physicians should pay more attention to protect the thyroid when children underwent CT scans, especially chest CT scans.