To study the changes of bone density after X-ray irradiation, the author has performed animal experiments using rats of 250 to 300 grams. Dual photon absorptiometry was used to scan several segments, head, humerus, lumbar vertebrae, femur, tibia,
tail
and total body.
Experimental animals were divided into two groups: those that received 4,000 rads and those with 10,000 rads. Bone densitometry were checked under ether anesthesia three times: before irradiation, 4 weeks and 8 weeks after. For histomorphometric
study,
proximal metaphysis of both humerus and femur were taken to make histologic after decalcification and hematoxylin-eosin staining, the volumes of trabecular as well as cortical bones were measured with Visual imaging data system.
@ES The results obtained were as follows:
@EN 1. In those received 4,000 rads of X-ray irradiation, bone mineral density was significantly decreased in both head and total body at 8 weeks while in those of 10,000 rads it was significantly decreased in lumbar vertebra, tibia and total
body
scans
at 8 weeks.
2. The percentages of bone loss after 4 and 8 weeks of irradiation were 1.7 and 4.4 percent in 4,000 rads group and 3.3 and 7.7 percent in 10,000 rads group.
3. Bone loss from irradiation was dose-dependent and seemed to be progressive till 8 weeks after irradiation.
4. Cortical bones also were damaged from earlier stage those the degree of bone loss was severe in trabecular bones.
With above results, it can be assumed that the X-ray irradiation do decreases bone density in rats through not only loss of estrogen induced by castration but also direct damage to the bones.
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