The Protective Effect of Estrogen Against Radiation Cataractogenesis is Dependent Upon the Type of Radiation

Individual response of the ocular lens to ionizing radiation

PURPOSE

Cataract (opacification of the ocular lens) is a typical tissue reaction (deterministic effect) following ionizing radiation exposure, for which prevention dose limits have been recommended in the radiation protection system. Manifestations of radiation cataracts can vary among individuals, but such potential individual responses remain uncharacterized. Here we review relevant literature and discuss implications for radiation protection. This review assesses evidence for significant modification of radiation-induced cataractogenesis by age at exposure, sex and genetic factors based on current scientific literature.

CONCLUSIONS

In addition to obvious physical factors (e.g. dose, dose rate, radiation quality, irradiation volume), potential factors modifying individual responses for radiation cataracts include sex, age and genetics, with comorbidity and coexposures also having important roles. There are indications and preliminary data identifying such potential modifiers of radiation cataract incidence or risk, although no firm conclusions can yet be drawn. Further studies and a consensus on the evidence are needed to gain deeper insights into factors determining individual responses regarding radiation cataracts and the implications for radiation protection.

First measurements of low-energy cosmic rays on the surface of the lunar farside from Chang'E-4 mission

Human activities on the lunar surface are severely constrained by the space radiation dominated by cosmic rays (CRs). Here, we report the first measurements of the low-energy (about 10 to 100 MeV/nuc) CR spectra on the lunar surface from China’s Chang’E-4 (CE-4) mission around the solar minimum 24/25. The results show that for the proton, helium, CNO, and heavy-ion groups, the ratios (ratio errors) of the CE-4 fluxes to those from the near-earth spacecraft are 1.05 (0.15), 1.30 (0.18), 1.08 (0.16), and 1.24 (0.21), respectively, and to those predicted by the models [CRÈME96 and CRÈME2009] are instead [1.69 (0.17), 2.25 (0.23)], [1.66 (0.17), 1.76 (0.18)], [1.08 (0.11), 1.07 (0.11)], and [1.33 (0.18), 1.17 (0.15)]. Moreover, a notable enhancement of ³He/⁴He ratio is observed at ~12 MeV/nuc, and the CR dawn-dusk symmetry is confirmed. These results provide valuable insights into the CRs on the lunar farside surface and will benefit future lunar exploration.

Sensitivity and latency of ionising radiation-induced cataract

When managed with appropriate radiation protection procedures, ionising radiation is of great benefit to society. Opacification of the lens, and vision impairing cataract, have recently been recognised at potential effects of relatively low dose radiation exposure, on the order of 1 Gy or below. Within the last 10 years, understanding of the effects of low dose ionising radiation on the lens has increased, particularly in terms of DNA damage and responses, and how multiple radiation or other events in the lens might contribute to the overall risk of cataract. However, gaps remain, not least in the understanding of how radiation interacts with other risk factors such as aging, as well as the relative radiosensitivity of the lens compared to tissues of the body. This paper reviews the current literature in the field of low dose radiation cataract, with a particular focus on sensitivity and latency.