Mice that received a single therapeutic dose of radiation
-- comparable to a single dose of radiation received
by human cancer patients -- lost as much as 39 percent
of the spongy portion of their inner bone, researchers
report.
That loss reduced the inner bone's weight-bearing
connections by up to 64 percent, the research team
added.
While the results of this mouse study cannot be directly
applied to humans, it does raise potential concerns
about cancer patients receiving radiation therapy
and radiation exposure for astronauts on long space
flights, the researchers noted.
"We were really surprised at the extent of bone
loss," lead researcher Ted A. Bateman, a Clemson
University bioengineer who studies bone biomechanics,
said in a prepared statement. "We're seeing bone
loss at much lower doses of radiation than we expected."
His team published the findings online in the Journal
of Applied Physiology.
The mice in the study received a single 2 Gray (Gy)
dose, which is comparable to the single 1-2 Gy dose
received by cancer patients, who receive a series
of doses over the course of their treatment, for a
total of between 10 to 70 Gy.
The mice suffered a loss of trabecular bone, the
spongy area of bone inside the dense outer cortical
bone.
"It's interesting that the trabecular bone,
not the cortical bone, suffered the damage,"
Bateman said.
The loss of spongy bone results in a less efficient
bone support structure, making the bone more susceptible
to fractures, the researchers said.
