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A scanning‐slit x‐ray videoabsorptiometric technique for bone mineral measurement
Author(s) -
Dobbins James T.,
Pedersen Per L.,
Mazess Richard B.,
Cameron John R.,
Hansen Jorgen L.,
Hefner Lance V.
Publication year - 1984
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.595554
Subject(s) - imaging phantom , materials science , femur , optics , linearity , detector , nuclear medicine , biomedical engineering , physics , medicine , surgery , quantum mechanics
An x‐ray videoabsorptiometric technique was developed for measurement of bone mineral content (BMC) in vivo . The principle utility of this technique is the precise measurement of commonly fractured bones, such as the femoral neck, that are difficult to measure by other techniques because of repositioning problems. Scanning slits reduce scattered radiation and improve linearity of measurements. Heavily filtered, high‐kVp beams are used to minimize errors from beam hardening, and data renormalization is employed to compensate for spatial nonuniformities of the beam and detector. Linearity of measured BMC over the range 0.8 to 5 g/cm 2 is very good ( r =0.998) and compares well to single‐ and dual‐photon absorptiometry. A 1.6% change in measured BMC is observed for a 10% change (∼2 cm) in tissue thickness while a 10% change in marrow type causes a 0.6%–0.8% change in BMC. Manual repositioning of a femur phantom revealed a variation of 0.84% over ten measurements when femur values were referenced to standards. A computer repositioning algorithm provides much easier identification of the region for analysis and yields comparable variation (0.9%).