Determining body composition using fan beam dual-energy x-ray absorptiometry
First Claim
1. A method of estimating body composition from x-ray measurements made with a fan-shaped distribution of x-rays comprising the steps of:
- scanning a body with a fan-shaped distribution of x-rays and with a detector of x-rays to derive dual-energy x-ray measurements for respective pixel positions conforming to a two dimensional projection of the body;
processing the x-ray measurements to derive estimates of projected body mass for the respective pixel positions;
further processing the estimates of projected body mass to derive estimates of true body mass for the respective pixel positions that account for the positions of attenuating material along raypaths from a source of the x-ray distribution to respective positions at the detector.
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Abstract
True body composition is estimated using a dual-energy, fan-shaped distribution of x-rays and signal processing that corrects for mass magnification and other effects due to the geometry of the measurement system. To avoid inaccuracies due to beam hardening and certain other effects, the thickness of attenuating material along respective raypaths is obtained through using a four-dimensional look-up table derived experimentally from step-wedge measurements. To correct for mass magnification effects due to using a fan-shaped distribution of x-rays, another look-up table and interpolation between table entries are used to convert projected mass to true mass.
173 Citations
5 Claims
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1. A method of estimating body composition from x-ray measurements made with a fan-shaped distribution of x-rays comprising the steps of:
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scanning a body with a fan-shaped distribution of x-rays and with a detector of x-rays to derive dual-energy x-ray measurements for respective pixel positions conforming to a two dimensional projection of the body;
processing the x-ray measurements to derive estimates of projected body mass for the respective pixel positions;
further processing the estimates of projected body mass to derive estimates of true body mass for the respective pixel positions that account for the positions of attenuating material along raypaths from a source of the x-ray distribution to respective positions at the detector. - View Dependent Claims (2, 3, 4, 5)
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