title: Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components.
abstract: We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed.
authors.affiliation: Dept. of Radiology & Biomedical Imaging, 1 Irving Street, CA, USA 94122.
authors.forename: Serghei
authors.initials: S
authors.lastname: Malkov
authors.affiliation: Dept. of Radiology & Biomedical Imaging, 1 Irving Street, CA, USA 94122.
authors.forename: John
authors.initials: J
authors.lastname: Shepherd
keywords: 3d optical imaging; body composition; dual-energy absorptiometry
references.citation: Phys Med Biol. 1998 Sep;43(9):2583-96
references.pmid: 9755947
references.citation: Am J Clin Nutr. 1992 Jul;56(1):19-28
references.pmid: 1609756
references.citation: J Biomech. 2009 Feb 9;42(3):217-22
references.pmid: 19106000
references.citation: Med Phys. 2009 May;36(5):1602-9
references.pmid: 19544776
references.citation: Sensors (Basel). 2012;12(2):1437-54
references.pmid: 22438718
references.citation: Med Phys. 2010 Jan;37(1):164-74
references.pmid: 20175478
references.citation: Am J Physiol. 1996 Dec;271(6 Pt 1):E941-51
references.pmid: 8997211