Online edition:ISSN 2758-089X


Vertebral Bone Mineral Density Measured with Dual Photon Absorptiometry Using a Gamma Camera: Clinical Application to Metabolic Bone Diseases

Dual photon absorptiometry (DPA) with a gamma camera, instead of a rectilinear scanner, has been developed for vertebral bone mineral density (BMD) measurement. The system consists of 50 mCi (1,850 MBq) 153-Gd as the emitting source, and an Anger-type gamma camera with a rectangular Nal (Tl) crystal and 22 photomultiplier tubes. The effective field of a view was enough to cover more than 3 vertebrae. With the patient sitting, data acquisition was performed. The spatial resolution and uniformity of the gamma camera were good. With the introduction of a correction equation, the error in calculated BMD due to body thickness was reduced. A data acquisition of 7.5 to 15 min led to a satisfactory C.V. value (less than 2.0%). The precision (1.63% of C.V. in vitro and 3.53% in vivo) and accuracy (r=0.999) of the BMD measurements were also good. Vertebral BMD values in 300 normal Japanese females decreased with aging. Although in involutional osteoporosis and secondary hyperparathyroidism both vertebral and radial % BMDs decreased, in steroid-induced osteoporosis and primary hyperparathyroidism, disproportionate bone loss (relatively lower in vertebral bone) was demonstrated. Thus, it was shown that a newly developed DPA system using a gamma camera provided sufficient precision and accuracy to quantificaticn of vertebral BMD, and its application should provide reliable information for clarification of the pathophysiology of metabolic bone diseases.

Fukunaga M, et al