Precision of dual-photon absorptiometry

Abstract

Precision of dual-photon absorptiometry (DPA) measurements was determined in a lumbar spine phantom and in humans. Approximately half of the measurements were made before and half after a 153gadolinium source change. The phantom was measured with different amounts of acrylic, which simulates human soft tissue, in order to evaluate the influence of body thickness on bone mineral density (BMD). Results of scans analyzed with two software versions from Lunar Radiation Corp., the widely used 08B and a prototype 08C, are compared. DPA with a cold source significantly overestimated BMD in the phantom in the presence of large amounts (more than 25 cm) of soft tissue equivalent with version 08B but not with the newer version 08C. Similarly, in nine subjects, there was a significant decrease in spine BMD after a source change when scans were analyzed with version 08B (mean difference 0.026 g/cm2, P = 0.002) but not with 08C (0.01 g/cm2, P = 0.234). No systematic effect of source change on femoral BMD measurements was observed. The SD of the mean difference of two measurements of the nine subjects was 0.019 g/cm2 (1.6% of the mean value) for the spine with software version 08B and 0.024 g/cm2 (2.0%) with version 08C, 0.03 g/cm2 (3.3%) for the femur neck, 0.03 g/cm2 (4.0%) for the greater trochanter, and 0.04 g/cm2 (4.9%) for Ward's triangle region of the proximal femur. The spine phantom was scanned on two other commercial bone densitometers in order to assess inter-instrument variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Recovery from severe osteoporosis following cure from ectopic ACTH syndrome caused by an appendix carcinoid

“…In the absence of degenerative changes at the lumbar spine, BMD increased by 79 % at this site over a 3-year period. The measurement error that may have been introduced by changes in body mass and tissue composition [8] in the follow-up period is in the order of 3 % [9], and thus, negligible compared to the overall increase in bone mass seen in this patient.…”

Normative values of lumbar spine mineral density and fracture threshold in Japanese measured by dual photon absorptiometry based on scinticamera methods (Dualomex HC-1)

“…For the measurement of bone loss in the lumbar spine, quantitative computerized tomography (QCT) (1/, dual photon absorptiometry (2), and dual energy X-ray absorptiometry (3~ are available. Dualomex HC-1 is a unique dual photon absorptiometer based on a scinticamera method utilizing a 153Gd source developed for the purpose of simplification of the method of measurement, decrease of the radiation exposure and reduction of the price.…”

Dual-energy X-ray absorptiometry in diagnosis of osteoporosis: Basic principles, indications, and scan interpretation

“…The precision error for spine and femur is 1.5% and 2%, respectively, in osteoporotic patients. [17][18][19][20][21][22] In the lumbar spine, each vertebra is measured separately, and those with severe degenerative disease or a fracture for example can be excluded from the analysis. Such information is obtained from the clinical history, radiographs, or the scan image.…”