Skeletal Nuclear Medicine

Abstract

Bone scan or bone scintigraphy (BS) is among the earliest diagnostic applications in NM imaging that remains useful today since its establishment in the early 1970s (Wikipedia Contributors. Bone scintigraphy. 16 October 2013 08:40 UTC; http://en.wikipedia.org/w/index.php?title=Bone_scintigraphy&oldid=577401413. Accessed 10 Dec 2013, 01:22 UTC, 2013). Current bone-seeking radiotracers can be divided into those emitting gamma rays (imaged with gamma cameras) or positrons (imaged with PET/CT). The former group is collectively called ^99mTc-polyphosphonates (^99mTc-PPs), which include ^99mTc-methylene diphosphonate and ^99mTc-hydroxymethylene diphosphonate. The latter group includes ¹⁸F-labeled sodium fluoride (Na¹⁸F). They are all administered intravenously and taken up by the skeleton through a process called chemabsorption whereby the tracer is incorporated into the calcium hydroxyapatite crystal (CHAC) matrix of the bone, which is laid down by osteoblasts. Thus, bone-seeking radiotracers reflect skeletal osteoblastic activity (Wong KK, Piert M, J Nucl MEd. 54(4):590–599, 2013). Sometimes the radiotracers can localize to pathological or dystrophic calcium depositions in soft tissues such as calcified metastatic liver lesions from colorectal cancer or calcium deposits in the lungs or stomach in hyperparathyroidism.