Bone scans: Putting your horse on the "hot" seat

Well, I started to prepare an article on this topic but the articles I found seemed so cogently written it seemed unnecessary for me to write yet another. Here's some very basic information and links to the articles I liked most.

Radiographs vs. bone scans
With radiographs (x-rays), the equipment is the radiation source, emitting X-rays, while bone scans make the subject radiate and a camera is used to detect the distribution of the radiactive substances in the body. Radiographs show changes in the structure of organs and tissue, while bone scans detect physiological changes--it measures the metabolism of the horse.

What bone scans measure
A bone scan, or nuclear scintigraphy, is a process where vets inject radioactive dye into the horse and measuare the "uptake" in target organs/tissues. An area of increased uptake is called a hot spot. Hot areas can be centers of inflammation/blood flow or increased activity of bone forming cells -- a healing fracture or active growth, for example. Bone scans are valued for their sensitivity in detecting early disease processes -- before a radiograph would catch a problem. In the diagnostic images shown, areas of uptake are in reds and yellows. Note that a young horse's bone scan will produce better image quality than an older horse, because their metabolism is more active.

RESOURCES

Equine Bone Scintigraphy: What is it and what can it do for me? from the University of Minnesota Vet School

Using bone scans to diagnose lameness by Heather Smith

Information for owners about equine bone scanning (from Liphook Equine Hospital)

Nuclear Scintigraphy from the book Lameness by Christine King

Scintigraphy: Get it while it's hot!