The Clemson University study findings, published in the Journal of Applied Physiology, showed that the effects of a single 2 Gray (Gy) dose of radiation caused the weight-bearing connections of the mice's inner bones to decrease up to 64 percent.
According to the researchers -- who admitted surprise that the radiation had affected the spongy trabecular bone rather than the dense outer cortical bone -- the significant loss makes for a less-efficient bone support structure, leaving the bone more vulnerable to fractures.
It is a cause for concern for the numerous cancer patients who undergo radiation therapy each year, as well as astronauts who could be exposed while on long journeys to space. Although the dosage was comparable to the 1- to 2-Gy dose a human cancer patient would receive, the effects on the mice cannot be directly correlated with how the radiation might affect humans.
A prepared statement by lead researcher Ted A. Bateman said, "We were really surprised at the extent of bone loss. We're seeing bone loss at much lower doses of radiation than we expected."
This statement could also have an impact on women who have been consistently instructed by their doctors to get mammograms "early and often," as this test emits low levels of radiation.