Nuclear Scintigraphy (bone scan) Flashcards
What molecule is nuclear scintigraphy based around
Technetium-99m (99mTc) is the unstable (radioactive) form of the element technetium
Describe how nuclear scintigraphy work
99mTc can be bonded by chelation to methylene diphosphate (MDP)
MDP binds to hydroxyapatite crystals in bone during osteoblastic activity.
MDP therefore binds to entire skeleton during normal bone turnover.
Describe what you would see on nuclear scintigraphy in places of disease bone
Diseased bone is undergoing greater osteoblastic activity as it tries to mend.
→ takes up more MDP (an necessarily more 99mTc)
→ more gamma radiation is emitted from that location
→ can be used to locate areas of the skeleton that are diseased
Before horse is injected with nuclear scintigraphy what should happen
Prior to injection the horse is exercised, rugged and has legs & feet wrapped.
→ causes peripheral vasodilation
→ protects limbs from urine splash (MDP is primarily excreted in urine)
when do you take nuclear scintigraphy images
begins 2 hours after injection
A gamma camera is used to detect emitted gamma radiation.
An anatomic image is created in the imaging computer.
Whole body / neck & forelimbs / neck, back, pelvis, hind limbs
How long does a horse undergoing nuclear scintigraphy need to be isolated
Isolation for 36-48 hrs
MDP is primarily excreted in urine
Bedding allowed to decay further before disposal
List 6 indications of nuclear scintigraphy
when regional anaesthesia has failed to locate source of pain
multi-limb lameness
when radiography not possible- suspected back/ pelvis problems
To confirm / reject a suspected diagnosis
Where a fracture is suspected
when lameness is intermittent/ horse is underperforming
Describe how to interpret nuclear scintigraphy images
Looking for areas emitting more gamma radiation than expected.
Compare left v right.
