Radiation Medicine and Protection最新文献

Breast cancer is the most frequently diagnosed malignant tumor in women worldwide and the leading cause of cancer death. Radiotherapy for breast cancer is readily accepted and widely used in clinical practice. Potential limitations with radiotherapy include treatment resistance, side effects, and complications caused by high doses of irradiation. The search has been on to locate an efficacious radiosensitizer. This review summarizes six currently approved pharmaceuticals that have also been investigated for off-label use as radiosensitizers in breast cancer.

Objective

To investigate the potential role of the regulator of G protein signaling 20 (RGS20) in radioresistance of non-small cell lung cancer (NSCLC).

Methods

A total of 35 lung adenocarcinoma (LUAD) patients from The Cancer Genome Atlas (TCGA), who underwent radiotherapy, were enrolled and divided into radiosensitive (n ​= ​16) and radioresistant (n ​= ​19) groups based on clinical prognosis. The expression and prognosis of RGS20 were analyzed by Gene Expression Profiling Interactive Analysis (GEPIA) database. A radioresistant cell line (A549R) was constructed by irradiating A549 ​cells with 6 ​Gy X-rays for 10 fractions. Cell survival was measured by colony formation assay. The regulatory effect of RGS20 on pyroptosis were verified by LDH release and Western blot assay, and the underlying mechanism was investigated by transfecting RGS20 siRNA and applying a GSDMD inhibitor).

Results

A total of 2,181 differentially expressed genes (DEGs) were identified by analyzing the data of radiosensitive and radioresistant individuals from the TCGA-LUAD dataset. These DEGs were enriched in G alpha (z) signalling events analyzed by Reactome database. RGS20 exhibited significant upregulation among the DEGs, and its higher expression predicted poor prognosis in LUAD patients. In vitro, the expression of RGS20 protein was increased by irradiation in A549 ​cells, whereas it remained at much high levels in A549R cells regardless of irradiation. After irradiation, the expressions of pyroptosis-related proteins were significantly increased in A549 cells (P ＜ 0.05), with no significant changes were observed in A549R cells. Treatment with LDC7559 significantly reduced LDH release (P ＜ 0.01) and improved the survival rate of irradiated A549 cells (P ＜ 0.01). Furthermore, knockdown of RGS20 gene in A549R cells significantly increased LDH release (P ＜ 0.001) and enhanced radiosensitivity (P ＜ 0.01), while LDC7559 administration reversed LDH release (P ＜0.01) and radiation-induced cell death increased by siRGS20 (P ＜0.05). Meantime, the increased expression level of GSDMD-NT was observed in A549 and A549R cells transfected with siRGS20 (P ＜ 0.05).

Conclusion

RGS20 contributes to the radioresistance of NSCLC cells, which might be a potential target for NSCLC radiotherapy.

Objective

To evaluate the equity of medical resources in radiotherapy and diagnosis in Shanghai, China, based on population, geography, and economic factors.

Methods

Data on medical resources including institutions, equipment, and staff in radiotherapy/diagnosis were collected from all 16 districts of Shanghai, China in 2022. Separate data were collected for institutions and devices in CT. The Gini coefficient (G) and Lorenz curves were used to assess fairness based on population and geography, while the Theil index (T) was employed to evaluate health equity based on economic factors. Health resource agglomeration degree (HRAD) and population agglomeration degree (PAD) were utilized to analyze the equity and accessibility of medical resources considering both population and geography.

Results

In 2022, Shanghai had a total of 992 institutions, 4,925 devices, and 10,282 personnel in radiotherapy and diagnosis. Additionally, there were 381 institutions conducting CT examinations and 776 CT machines in Shanghai. The Gini coefficients for institutions, devices, and personnel in radiotherapy and diagnosis based on population ranged from 0.2 to 0.4, while for CT, the Gini coefficients for institutions and devices ranged from 0.2 to 0.4. When considering geography, all Gini coefficients were greater than 0.5. The results of the Theil index indicated that inequities in distribution may be influenced by economic factors. The HRAD and PAD revealed disparities in the accessibility of institutions, devices, and personnel in radiotherapy/diagnosis and CT in Shanghai.

Conclusions

Inequities in the distribution of institutions, equipment, and personnel for radiotherapy/diagnosis and CT were observed in Shanghai in 2022, both geographically and economically. There is a critical need to enhance the allocation of resources for radiological equipment and personnel and to establish a scientifically robust urban resource planning framework.

Objective

To investigate the substantial changes in cell types, pathways, and cell-cell interactions occurring in the irradiation-induced alopecia and dermatitis (IRIAD) mouse model and to identify potential targets for patients experiencing skin adverse reactions to radiotherapy.

Methods

Mice were irradiated at 15 ​Gy, targeting the head and neck region. After a 14-day interval, living cells were extracted from both wild-type (WT) mice and irradiated mice for single-cell RNA sequencing (scRNA-seq). The scRNA-seq data, retrieved from the GEO database (GSE201447), underwent stringent quality control using the Seurat (v4.3.0) R package. Cell type annotation relied on previously reported typical markers and CellMarker 2.0. Differentially expressed genes were calculated to perform gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Cell-cell interactions were evaluated using the Cellchat R package.

Results

The application of single-cell RNA sequencing (scRNA-seq) enabled a comprehensive characterization of the intricate cellular composition of both wild-type (WT) and irradiated mice skin. Remarkably, cells within irradiated mice skin exhibited a significant alteration in the intensity of cell-cell interactions compared to their wild-type counterparts. This change in interaction intensity was observed across various cell types, including fibroblast cells, endothelial cells, and dendritic cells. Importantly, these "interacting cells" shared common signaling pathways, notably the upregulation of the IL-17 pathway following irradiation.

Conclusions

The modification of intercellular communication induced by irradiation primarily involves fibroblast cells, endothelial cells, and various types of immune cells. This investigation provides a novel perspective on potential targets and holds promise for enhancing the clinical management of IRIAD.

Objective

To validate the safety and efficacy of chronochemotherapy for locoregionally advanced nasopharyngeal carcinoma (NPC).

Methods

Participants for this phase II randomized controlled trial were recruited from the Department of Head and Neck Oncology at the Affiliated Cancer Hospital of Guizhou Medical University. Patients enrolled (128 in total, 112 in the final analysis) between April 1, 2017, and February 28, 2018, were randomly divided into the chronochemotherapy and conventional chemotherapy groups. In the chronochemotherapy group, docetaxel was intravenously administered between 3:30 a.m. and 4:30 a.m. on day 1, followed by intravenous administration of cisplatin between 10:00 a.m. and 10:00 p.m. from day 1to day 5. In addition, 5-fluorouracil was administered through a continuous intravenous pump between 10:00 p.m. and 10:00 a.m. (2nd day) from day 1 to day 5. In the conventional chemotherapy group, docetaxel (on day 1), cisplatin (on day 2), and 5-fluorouracil (from day 1 to day 5, 120 ​h in total) were administered without time-specific constraints. Both groups underwent intensity-modulated radiation therapy with 6-MV X-rays. The gross target volume (GTV) comprised the nasopharyngeal GTV and cervical lymph node GTV. The primary endpoint was immune function, quantified by measuring dendritic cell and lymphocyte subsets, whereas the secondary endpoints were therapeutic efficacy and incidence of adverse events. Pearson Chi-square test was applied to compare total events between the groups, Mann-Whitney U test was used to compare the DC subsets and toxicities, and Wilcoxon signed-rank test ​was used to compare the continuous variables between the two groups.

Results

Chronochemotherapy preserved immune function, as evidenced by elevated levels of myeloid dendritic cells (P ​= ​0.394) and higher CD4/CD8 ratio (P ​= ​0.781). No significant difference in overall response rate, measured as the sum of complete and partial response rates, was observed between the groups (P ​= ​0.711). A reduction in the incidence of vomiting (P ​= ​0.002), stomatitis (P ​= ​0.028), and mucositis (P ​= ​0.028) was observed in the chronochemotherapy group. Leukopenia incidence rate was 83.3 ​% and 92.3 ​% in the chronochemotherapy and conventional chemotherapy groups, respectively (P ​= ​0.232).

Conclusions

In patients with locoregionally advanced NPC, the overall response rate of chronochemotherapy is comparable to that of conventional chemotherapy; however, chronochemotherapy shows fewer adverse events.

Objective

To evaluate the effectiveness of a portable thyroid radioiodine meter in on-site monitoring to enhance the monitoring precision of radioiodine inhaled by nuclear medicine staff and patients.

Methods

A portable thyroid radioiodine meter was developed to measure the ¹³¹I activity in the thyroid. Performance tests of the portable thyroid radioiodine meter were conducted using calibration sources and testing methodologies adhering to national metrological standards.

Results

The thyroid radioiodine meter exhibited integral non-linearity, 8-h measurement stability, measurement linearity, and an energy resolution of 0.42%, 1.05%, 1.56%, and 7.11%, respectively for ¹³⁷Cs at 661.66 ​keV. Additionally, its minimum detectable activity for ¹³¹I at 364.49 ​keV was approximately 22 Bq (10 ​min).

Conclusion

The developed thyroid radioiodine meter features elevated performance and great potential for application in nuclear medicine and monitoring of responses to nuclear or radiological emergencies.

Objective

To explore the reduction effect for the indoor ²²²Rn (Rn) by Fresh Air Ventilation (FAV) system, a novel commercial ventilation device in China.

Methods

The indoor concentrations of Rn and its decay products (RnD) in three residential rooms, two in Beijing and one in Hefei city, Anhui province, before and after FAVS functioned were measured using an active continuous method. The air exchange rate was monitored by measuring CO₂ concentration using the tracer gas method.

Results

In the three rooms, the FAVS reduced the Rn concentrations from (162 ​± ​80) Bq/m³ to (63 ​± ​22) Bq/m³ and decreased the RnD concentrations from (64 ​± ​35) Bq/m³ to (13 ​± ​6) Bq/m³ on average, a decrease of (59 ​± ​25)% in the Rn concentrations and a drop of (77 ​± ​18)% in the RnD concentrations. Considering dose conversion factors of Rn and RnD, FAVS decreased the exposure dose by (76 ​± ​20)%. Besides, FAVS increased the air exchange rates from 0.17 h⁻¹ to 0.56 h⁻¹ on average.

Conclusions

FAVS can effectively reduce indoor Rn and RnD concentrations by improving the air exchange, serving as a valuable supplement to existing radon mitigation methods, especially in extreme climates.

The annex A of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2020/2021 Report presented a comprehensive global estimate of frequencies and doses from medical exposure to ionizing radiation, their distribution and trends for the period 2009–2018. The annex considered four general categories of medical practice using ionizing radiation: (a) diagnostic radiology, including dental radiology and computed tomography, (b) interventional radiology (image-guided interventional procedures), (c) nuclear medicine, and (d) radiation therapy. In the period 2009–2018, about 4.2 billion medical radiological examinations were performed annually, resulting in an annual effective dose of 0.57 ​mSv per caput. The use of computed tomography has continued to grow and the contribution from interventional radiology has increased rapidly in recent years. The annual number of radionuclide therapy treatments has increased by 60% since the UNSCEAR 2008 Report, while the number of courses of radiation therapy has increased by 22%. Medical exposure remains by far the largest human-made source of radiation exposure to the public. The Committee's evaluation relies on the collection of up-to-date and representative exposure data from all Member States of the United Nations. Future exposure survey should be more relevant and useful and adapted to changing data sources and changing uses of radiation across the world.

The hematopoietic system is susceptible to ionizing radiation (IR), which can cause acute hematopoietic failure or long-term myelosuppression. As the most primitive cells of the hematopoietic hierarchy, hematopoietic stem cells (HSCs) maintain lifelong hematopoietic homeostasis and promote hematopoietic regeneration during stress. Numerous studies have shown that nuclear and mitochondrial genomes are the main targets of radiation injury in HSCs. More importantly, the damage of DNA may trigger a series of biological responses that largely determine HSC fate following IR exposure. Although some essential pathways and factors involved in DNA injury and damage in HSCs have been revealed, a comprehensive understanding of the biological effects of radiation on HSCs still needs to be improved. This review focuses on recent insights into the molecular mechanisms underlying DNA damage and repair in HSCs after IR. Then summarize corresponding regulatory measures, which may provide a reference for further research in this field.

The annex D of the United Nations Scientific Committee on the Effects of Atomic Radiation （UNSCEAR） 2020/2021 Report presented a comprehensive global estimate of occupational exposure to ionizing radiation. The worldwide annual number of workers exposed to natural and human-made sources of ionizing radiation was estimated to be approximately 24 million in the period 2010–2014. About 52% of those were employed in the sectors that involve exposure to natural sources of radiation. The worldwide average annual effective dose for all workers during the period 2010–2014 was estimated to be around 1.2 ​mSv – about two thirds of the value estimated for the period 1995–1999. The annual effective dose was estimated to be around 2.0 ​mSv for workers exposed to natural sources and 0.5 ​mSv for workers exposed to human-made sources. The overriding limitation of current evaluation was the low rate of participation by United Nations Member States in providing occupational exposure monitoring data, especially data from non-nuclear sectors and occupational sectors involving naturally occurring radioactive materials. As the assessment of the worldwide occupational exposure is a complex task, the Committee relies on the collection of up-to-date data on occupational exposure from United Nations Member States in a broad range of occupational sectors, and continues collaboration with international organizations.