Accuracy of dual-photon absorptiometry compared to computed tomography of the spine
Dual-photon absorptiometry (DPA) was done using Gd-153 (44 and 100keV) in vivo and on various bone specimens including 39 vertebrae and 24 femora. The precision error for triplicate determinations on individual vertebrae was 3.3%, 2.9%, and 1.7% for bone mineral content (BMC), projected area, and areal density of bone mineral (BMD) respectively. The accuracy of determinations was 3-4% on the femora and 5% on the vertebrae. Computed tomography (CT) determinations were done on seven vertebrae immersed in alcohol (50%) to simulate the effects of marrow fat. CT measurements were done using a dual-energy scanner (Siemens) from which single-energy data files also were analyzed. There was a high correlation between Gd-153 DPA scans and either single- or dual-energy CT scans of the same vertebrae (rapprox. =0.97). For dual-energy CT the determined bone values were only 2% higher than the Gd-153 DPA values; however, single-energy CT scans showed a marked deviation. The CT values at 75kVp were 38% lower than those obtained from dual-energy CT scans or from Gd-153 DPA scans, while the values at 125kVp were 46% lower. Calcium chloride solutions made up with 50% alcohol showed the same systematic error of single-energy CT. Dual-energy determinations are mandatory on trabecular bone in order to avoid the errors introduced by variable marrow fat. The magnitude of the latter error depends upon the energy of the CT scan.
- Research Organization:
- Dept. of Medical Physics, Univ. of Wisconsin, Madison, WI
- OSTI ID:
- 7088268
- Report Number(s):
- CONF-840619-; TRN: 87-008885
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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VERTEBRAE
COMPUTERIZED TOMOGRAPHY
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ACCURACY
ALCOHOLS
BONE MARROW
CALCIUM CHLORIDES
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IN VIVO
KEV RANGE 10-100
PHOTONS
ALKALINE EARTH METAL COMPOUNDS
ANIMAL TISSUES
BETA DECAY RADIOISOTOPES
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CALCIUM HALIDES
CHLORIDES
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DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
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EVEN-ODD NUCLEI
GADOLINIUM ISOTOPES
HALIDES
HALOGEN COMPOUNDS
HEMATOPOIETIC SYSTEM
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INTERMEDIATE MASS NUCLEI
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KEV RANGE
MASSLESS PARTICLES
NUCLEI
ORGANIC COMPOUNDS
ORGANS
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RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SKELETON
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550602* - Medicine- External Radiation in Diagnostics- (1980-)