NASA has encouraged studies on 226Ra deposition in the human brain to investigate the effects of exposure to alpha particles with high linear energy transfer, which could mimic some of the exposure astronauts face during space travel. However, this approach was criticized, noting that radium is a bone -seeker and accumulates in the skull, which means that the radiation dose from alpha particles emitted by 226Ra would be heavily concentrated in areas close to cranial bones rather than uniformly distributed throughout the brain. In the high background radiation areas of Ramsar, Iran, extremely high levels of 226Ra in soil contribute to a large proportion of the inhabitants' radiation exposure. A prospective study on Ramsar residents with a calcium -rich diet was conducted to improve the dose uniformity due to 226Ra throughout the cerebral and cerebellar parenchyma. The study found that exposure of the human brain to alpha particles did not significantly affect working memory but was significantly associated with increased reaction times. This finding is crucial because astronauts on deep space missions may face similar cognitive impairments due to exposure to high charge and energy particles. The current study was aimed to evaluate the validity of the terrestrial model using the Geant4 Monte Carlo toolkit to simulate the interactions of alpha particles and representative cosmic ray particles, acknowledging that these radiation types are only a subset of the complete space radiation environment.

Permafrost in circum-polar regions has been recently undergoing thawing, with severe environmental consequences, including the release of greenhouse gases and amplification of global warming. Although highly important, direct methods of tracking thawing hardly exist. In a research study conducted at Adventdalen, Svalbard, we identified a permafrost radioisotope fingerprint, and show that it can be used to track thawing. Ratios of long- to the shorter-lived radium isotopes are higher in ground ice than in active layer water, which we attribute to the permafrost closed system and possibly to the long residence time of ground ice in the permafrost. Also, daughter-parent Ra-224/Ra-228 ratios are lower in permafrost than in the active layer. These fingerprints were also identified in a local stream, confirming the applicability of this tool to tracing thawed permafrost in periglacial watersheds. A combination of radium isotope ratios and H-3 allowed the identification of recent intra-permafrost segregation processes. The permafrost radium fingerprint should be applicable to other permafrost areas, which could assist in regional quantification of the extent of permafrost thawing and carbon emissions to the atmosphere.