In this work, a novel PAQUS apparatus was developed for in vivo assessment of the calcaneus. We first made lattice-shaped cubic phantoms of varying density, resulting in different BVF. PA absorbance at 740 nm (hemoglobin) and 930 nm (lipid) were significantly different across phantoms. Next, we created two anatomic phantoms based on a human calcaneus microCT volumetric image, and artificially eroded the trabecular structure on one to reduce BVF by 32.5%, mimicking osteoporosis-mediated bone loss. Phantoms were measured repeatedly and also significantly differed. Lastly, in vivo bilateral PA measurement was conducted at the calcaneus on 32 female Caucasian subjects (20-74 yrs). A significant difference in PA absorption was observed at 740 nm between younger (<50 yrs) and older (>50 yrs) subjects.
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