Bone scan (nuclear scintigraphy) is used to help identify difficult lameness problems and other skeletal problems. The entire horse (or a large portion) is imaged all at once, allowing detection of conditions difficult to find otherwise. Even a large, heavily muscled areas like the pelvis can be imaged, a unique attribute of this technology.
Nuclear scintigraphy is unique among the imaging modalities because it visualizes an active biologic process, it is not just a snapshot of structural anatomy.
A radioactive compound (technetium) is attached chemically to a “bone seeking molecule.” This hybrid molecule is injected intravenously into the horse. It migrates in high concentration to areas of bone mineral turnover, especially areas of inflamed or injured bone. The entire skeleton is thus “radioactive” for several hours.
The horse is then photographed with a gamma camera and the images are analyzed. Injured areas with high rates of bone turnover have much higher levels of radioactivity and appear very dark in the images.
Reasons to UseRelated Observations
The entire horse can be imaged at once, meaning that a survey of the whole horse is possible. This is a unique attribute of scintigraphy and one of the most important.
Bones in large, heavily muscled areas can be imaged. Early bone change can be discovered sometimes before visible change is seen on radiographs.
Scintigraphy defines a location where bone turnover is taking place, but does not provide information as to the cause. It also does not show great detail.
Nuclear medicine is only available at larger private practices and university teaching hospitals. It is also costly, which is due in part to the heavy regulation. Management of radioactive medications and waste are carefully controlled. Horses are radioactive for a short period of time following the procedure and generally stay at the facility for 24 hours.
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