An ultrasonic phantom for cortical and cancellous bone

Abstract

There is interest in developing ultrasonic techniques for diagnosing osteoporosis. Many techniques perform measurements at skeletal sites such as the heel, hip, and spine where the bone tissue consists of a non-porous outer layer of cortical bone that surrounds a porous interior region of cancellous bone. The goal of the present study was to develop an ultrasonic phantom that simulates this tissue configuration. A block of polymer open cell rigid foam (OCRF) was partially embedded in a thin layer of clear epoxy casting resin to create the phantoms. The resulting phantoms were 40mm × 40 mm × 20 mm with one 40 mm × 40 mm face embedded in ∼3mm of resin. Ultrasonic measurements were performed to characterize the speed of sound and attenuation of the resin and the OCRF separately and together, as configured in the phantom. Backscatter measurements were also performed. The resulting specimens can be used to investigate how non-normal incidence of an ultrasonic wave on the bone cortex may produce errors in these measurements.