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Local x‐ray tomography for in vivo bone structure examinations
Author(s) -
Laib Andres,
Rüegsegger Peter
Publication year - 1999
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 - 10.1118/1.598536
Subject(s) - tomography , nuclear medicine , cancellous bone , image resolution , quantitative computed tomography , materials science , medicine , radiology , bone density , osteoporosis , physics , optics , pathology , endocrinology
Precise information about the microarchitecture of cancellous bone would be helpful to further fracture risk prediction in individual patients. Recently 3D‐QCT of the distal radius has been introduced to this end. The validity of this new procedure is limited by the spatial resolution of the CT images, which in turn is limited by the x‐ray dose. Local tomography, where only the region of interest has to be scanned with x rays, might provide a way out of this dilemma. In this work the feasibility of local tomography for in vivo trabecular bone structure assessment is studied. In a first part the accuracy of structural indices obtainable with local tomography is compared with the accuracy of results from global (traditional) tomographic measurements. The results show that local tomography generates no substantial degradation in the structural indices. In a second part, the reduction in the radiation dose of local tomography is quantified with Monte Carlo simulations of the x‐ray scanning procedure. The results show that skin dose at the lower forearm can be reduced by a factor of 4–6, if the CT measurements are restricted to the distal radius. We conclude that with the help of local tomography in vivo 3D‐QCT examinations of the trabecular bone microarchitecture are feasible with a skin dose of 0.1 mGy at 165 3 μ m 3resolution, or with a skin dose of 1 mGy at a resolution of 100 3 μ m 3 . The increased resolution is expected to further improve the accuracy and precision of current in vivo bone structure examinations, allowing a detailed analysis of the processes of bone changes due to aging, disease, and treatment.