Bone scintigraphy

[4] Bone scintigraphy has higher sensitivity but lower specificity than CT or MRI for diagnosis of scaphoid fractures following negative plain radiography.

This leads to a limitation of the applicability of this imaging technique with diseases not featuring this osteoblastic (reactive) activity, for example with multiple myeloma.

In a typical bone scan technique, the patient is injected (usually into a vein in the arm or hand, occasionally the foot) with up to 740 MBq of technetium-99m-MDP and then scanned with a gamma camera, which captures planar anterior and posterior or single photon emission computed tomography (SPECT) images.

[19][14] In order to view small lesions SPECT imaging technique may be preferred over planar scintigraphy.

MDP renal clearance is not affected by urine flow rate and simplified data analysis can be employed which assumes steady state conditions.

However, disadvantages include higher rates of protein binding (from 25% immediately after injection to 70% after 12 hours leading to the measurement of freely available MDP over time), and less diffusibility due to higher molecular weight than [18F]NaF, leading to lower capillary permeability.

Patient experience is improved as imaging can be started much more quickly following radiopharmaceutical injection (30–45 minutes, compared to 2–3 hours for MDP/HDP).

Bone scan showing multiple bone metastases from prostate cancer .