Frequently Asked Questions About Nuclear Scintigraphy:
In general, the indication for bone scanning is to identify and describe physiologic information that cannot be discerned by other imaging methods. For instance:
- Competition horse not performing up to athletic expectations.
- Severe lameness of unknown origin.
- Difficult multiple limb lameness.
- Suspected fracture with no radiographic evidence.
- Lameness localized to a general area with no radiographic or ultrasonographic abnormalities apparent.
- Horse suffers from a lesion that induces a lot of bone metabolism such as: stress fractures, ligamentous avulsions, sclerosis, osteomyelitis, etc.
How is the bone scan performed?
Upon arrival at the clinic, the patient is injected intravenously with a short acting radio-isotope, Tc 99 MDP, linked to bone tracer agent. If appropriate, the horse is next exercised on the lunge pad in order to evaluate the lameness. Following the evaluation, the patient is stabled in a secure stall for approximately two hours while the radio-isotope circulates systemically throughout the horse's body. The horse is next tranquilized (standing sedation) and imaged with the gamma camera. Areas of bony inflammation are indicated in the computerized pictures as areas of increased uptake and described as focal or diffuse and mild, moderate or intense.
How long does the procedure take?
Depending on whether a hindend, frontend or a full body bone scan is performed, the procedure usually takes place several hours after the radio-isotope has been injected. Therefore, the bone scan images are often not read by the doctors until the late evening or early the following morning. After reviewing the images, the doctors devise the best plan for more extensively working up the lameness including: additional nerve blocks, intra-articular injections, digital radiographs, ultrasound, etc. Prior to the work-up and therapeutic treatment, the owner will be contacted to discuss the bone scan findings and further diagnostic options.