Experimental model for irradiating a restricted region of the rat brain using heavy-ion beams

Heavy-ion beams have the feature to administer a large radiation dose in the vicinity of the endpoint in the beam range, its irradiation system and biophysical characteristics are different from ordinary irradiation instruments like X-rays or gamma-rays. In order to get clarify characteristic effects of heavy-ion beams on the brain, we have developed an experimental system for irradiating a restricted region of the rat brain using heavy-ion beams. The left cerebral hemispheres of the adult rat brain were irradiated at dose of 50Gy charged carbon particles (290MeV/nucleon 5mmspread-out Bragg peak). After irradiation, the characteristics of the heavy-ion beams and the animal model were studied. Histological examination and measurement showed that extensive necrosis was observed between 2.5mmand7.5mmdepth from the surface of the rat head, suggesting a relatively high dose and uniform dose was delivered among designed depths and the spread-out bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. We believe that our experimental model for irradiating a restricted region of the rat brain using heavy-ion beams is a good model for analyzing regional radiation susceptibility of the brain

Particle radiation effects on mouse brain cells in vitro.

Low-Dose Particle Biology and Emerging Issues in Hadron Therap

Effects of Space Radiation for the hole body under the Space Environments

日本放射線影響学会第４８回大

Caution required for handling genome editing technology

Genome-editing technology, although a robust tool for genetic engineering, is creating indistinct regulatory boundaries between naturally occurring and modified organisms. However, researchers must act with caution in research and development to avoid misleading society. Furthermore, appropriate regulations should be proactively discussed and established for handling genome-editing technology

Effects of Low Dose Particle Radiation to Mouse Premature Neurons in Culture

Effects of low dose heavy particle radiation to central nervous system (CNS) were studied using mouse neonatal brain cells in culture exposed to heavy ions and X ray at fifth days of the culture. The applied dose varied from 0.05Gy to 2.0Gy. The subsequent biological effects were evaluated by an induction of apoptosis and the survivability of neurons focusing on the dependencies of (1) the animal strains with different genetic types, and (2) LET of the different nucleons. Of the three mouse strains tested, SCID, B6 and C3H, for brain cell culture, SCID was the most sensitive and C3H the least sensitive to both X-ray and carbon ion (290MeV/n) when compared by 10 % apoptotic induction. However, the sensitivity differences among the strains were much smaller in case of carbon ion comparing to that of X-ray. The LET dependency was compared with using C3H and B6 cells exposing to different ions, proton (H, C, Ne, Ar, and Fe). Although no detectable LET dependency was observed at higher dose than 1 Gy, an enhancement was observed in the high LET (85 -200 KeV/_m) and low dose (<0.5 Gy) regions. The survivability profiles of the neurons were different in the mouse strains and ions.14th IAA Humans in Space Symposi

LET Dependent Recovery of Mouse Hematopoietic Stem Cells from Particle Irradiation

Radiation induced acute changes of mouse heamatopoietic functions and its recovery were studied in different LET of heavy ions, carbon (13keV/mm and 30 keV/mm), neon (32 keV/mm and 55 keV/mm), silicon (56 keV/mm), argon (85 keV/mm) iron (200 keV/mm). After whole body irradiation was applied up to 3 Gy, the subsequent heamatopoietic parameters were followed by the blood analysis for 3 weeks, All functions, spleen weight, WBC, hemoglobin concentration, granulocyte-monocyte colony forming unit (GM-CFU) in bone marrow and spleen indicated dose dependent reduction within 2 days after the irradiation and followed by a slow recovery. Complete recovery took approximately 3 weeks for all functions. GM-CFU in spleen showed the highest sensitivity to all particles indicating a large reduction down to less than 1 % of control at 3 Gy exposured. Of the particle exposed Si (55 keV/mm) induced the largest effects and the slowest recovery, whereas Fe (200 keV/mm) indicated signidicantly the lsast effects and quick recovery. The results suggested a strong LET dependency of the heamatopoietic progenitor cells which may have a RBE maximun less than 100 keV/mm. The recovery kinetics inducated non-monotonic increase within 10 days suggested an involvement of time dependent releases of cytokines (IL-1b ___ IL-3) which may modify the proliferation of hematopoietic cells.12th International Congress of Radiation Researc

Particle radiation effects of mice hematopoietic stem cells in vivo.

The 2nd International Workshop on Space Radiation Researc