The lens is one of the organs at risk (OAR) in radiotherapy for brain tumors and the head and neck cancer. The tolerable dose is low compared to other OARs, and in cases where the tumor is near the lens, the tolerable dose will be exceeded. In this study, we retrospectively investigated the development of cataract after radiotherapy in patients with brain tumors and head and neck cancer. Among 76 patients with brain tumor, maxillary sinus cancer, orbital sarcoma, oral cavity cancer, buccal mucosal cancer, and nasopharyngeal cancer, we reviewed follow-up records of 43 patients (86 lenses). These patients were treated in Hirosaki University Hospital. The lens dose was estimated by dose volume histogram calculated using radiotherapy planning system. Among the 43 patients (86 lenses) investigated, 5 patients (6 lenses) developed cataracts (6.98%). Of which, four lenses were from patients with maxillary sinus cancer, one with orbital sarcoma, and one with nasopharyngeal cancer. The univariate analysis using Cox proportional hazards regression was performed to examine the clinical features of cataract development. Sex, age, smoking, drinking alcohol, and hypertension, which were reported to be associated with the onset of the cataract, were not significantly correlated in this study. Only lens dose classified according to tolerable dosage of 1,000 cGy was significantly associated (P = 0.048), with a hazard ratio of 8.830 (95% CI: 1.020–76.440). The cumulative incidence function indicated that the incidence was significantly higher in the sub-group that exceeded the tolerable dose (P = 0.020). In addition, there was a negative correlation between lens dose and latent period (r = -0.521). The median lens dose was the highest for orbital sarcoma (1973.2 cGy), followed by maxillary sinus cancer (1425.1 cGy). Additionally, the median lens dose in brain tumors exceeded the tolerable dose (1243.4 cGy). In comparison with the 3 dimensional-conformal radiotherapy, the lens dose was lower and no patients developed cataract in the intensity modulated radiotherapy (IMRT) method. Radiotherapy for tumors located in close proximity to the lens often results to a high lens dose, with many instances exceeding the tolerable dose, thereby increasing the risk of developing cataracts. Conversely, employing the IMRT technique has demonstrated the ability to reduce lens dose and risk of cataract development.

This study measured radon (222Rn) concentrations in soil gas and ambient dose equivalent rates in various neighborhoods of Yaoundé, Cameroon. MARKUS 10 detector was used to measure radon in soil gas at 50 cm of depth. The ambient dose equivalent rate measurements were performed at the height of 1 m above ground, using a pocket survey meter (RadEye PRD-ER, Thermo Scientific). The results obtained from the radon concentration in soil gas measurements ranged from 8.4 to 50.7 kBq m-3 with a geometric mean of 25.4 kBq m-3. Ambient dose equivalent rates ranged from 0.02 to 0.11 μSv h-1 with an average value of 0.05 μSv h-1. These measurements were followed by calculating radon surface exhalation rates, and the annual outdoor external effective dose. Radon surface exhalation rates ranged from 41.5 to 250.5 mBq m-2 s-1 with an average value of 139.8 mBq m-2 s-1. The annual outdoor external effective dose varied between 0.07 and 0.39 mSv with an average value of 0.17 mSv. The correlation between radon concentration in soil gas and ambient dose equivalent rates was analyzed. A Pearson correlation coefficient r = 0.81 was obtained, indicating the strong correlation between them, and one can serve as the indicator of the other.

A commercially available tritium enrichment system was improved to provide rapid and high efficiency enrichment. Two smaller tanks of double-glazed glass were installed to realize better cooling of sample water at 15 °C. The improved system kept the sample water in the tanks cooler than in the large tanks of the original design. The tritium enrichment factor ranged from 5.24 to 5.50 with the mean value (± standard deviation) of 5.40 ± 0.10 and those values were higher than observed for operation before the improvement. The results obtained with the improved system were maintained at a high tritium enrichment factor.

Japan has experienced complex disasters in recent years, including radiation disasters, which have made evacuation of older individuals critical. In October 2023, we visited Taiwan, which has an aging population and disaster risk similar to Japan. This study highlights the disaster preparation endeavors of long-term care facilities (LTCFs) and the government using examples of daycare centers for older individuals; firefighting experts conducting mandatory accident and injury prevention; and evacuation drills in response to fire, earthquakes, and other disasters. The Ministry of Health and Welfare (MOHW) has centralized the management of medical information and information on LTCFs; however, this is not centrally integrated. To facilitate disaster management and evacuation, central integration and management of medical and LTC information is necessary. Reflecting on the aforementioned issues, the integration and management of medical and LTC information at the central and domestic levels and the delay of information needed for disaster management should be considered when considering disaster preparedness for Japan and Taiwan.

Human health effects due to several factors originating from volcanic activity have been observed around volcanos. This report summarizes a preliminary survey of the ambient dose equivalent rate and PM2.5 and PM10 in Catania, Italy, where one of the most active volcanoes of Mt. Etna is located. The ambient dose equivalent rate and indoor radon concentration were higher than those in other countries, probably because of the volcanic rocks used as building materials. In contrast, the concentrations of PM2.5 and PM10 during the survey were low, indicating that the air quality was clean. Further detailed investigations will be conducted in the future.