Nuclear Scintigraphy (Bone Scan)
A Now-Integral Diagnostic Tool in Equine Care
Nuclear scintigraphy, or bone scan, has become an integral part of the equine veterinary diagnostic process.
Indications for use include:
- Lameness involving multiple limbs or sites
- Earlier detection of stress fractures that, if left untreated, could have severe or even catastrophic results
- Defining the extent/severity of an area of injury identified with other diagnostic modalities
- Horses with decreased performance or just “not quite right,” subtle or intermittent lameness and where other imaging failed to give a diagnosis
- Imaging of areas such as the back or pelvis (requires general anesthesia for radiographs)
- Evaluation of soft-tissue injuries at bone attachments and to evaluate blood flow concerns to the limb
- Monitoring the healing process – to confirm lesions have healed
- Horses with severe needle phobias, thus limiting use of nerve blocks
How does it work? The procedure begins with injection of a radioisotope intravenously. Soft-tissue scans of a specific area are obtained in the first 15 minutes, and then the bone images are acquired two to three hours later.
The horse is sedated and positioned next to a scintillation camera, which houses a crystal. The crystal absorbs the gamma rays emitted from the patient and creates an anatomic image on a computer. Areas with increased bone turnover (inflammation) emit higher concentrations of gamma rays, referred to as increased radio uptake (IRU) or hot spot. Within 30 hours of initial injection, the patient will have less than 3% of the radioisotope left in its system. Horses are required to be quarantined until they are no longer releasing radioisotopes above a certain level, usually 36 to 48 hours after injection. – Pam Poole, LVT
The unit is housed at Pegasus Training and Rehabilitation Center. The scans are performed by Pilchuck’s Dr. Jim Bryant and Pam Poole, LVT, and Katie Gilmur, rehab assistant at Pegasus.