Acute patho-hematological changes observed in mice following administration of high doses of tritiated water (HTO)

Various doses (0, 10, 15, 20, 40, and 80 mCi/0.5 ml) of tritiated water (HTO) were injected intraperitoneally to 6- to 7-week-old female C57BL/6N mice. The mice were examined in terms of survival rate, body weight, changes in white blood cell counts, changes in organ weight, and pathohistological findings of the bone marrow, thymus, spleen, digestive tract, ovaries, kidneys, lungs, and adrenal gland. All mice receiving 20 mCi or more of HTO died, but all mice receiving 10 mCi survived. This seemed to support the previous report describing that LD50 of HTO is approximately 0.9 mCi/body weight (g) and the accumulated dose is 804 rad. Dose-dependent effects of HTO on atrophy and tissue damage were seen in the hematopoietic system, digestive tract and genital organs. Unlike radiostrontium and radioiodine, HTO had no specific affinity to organs, and HTO-induced organ damage was analogous to that induced by whole body irradiation with beams of low linear energy transfer. (Namekawa, K.)