# US 5,348,009 A · Bone assessment apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,009 A - Document ID: US5348009A - Status: Granted - Kind: A - Application number: 08/063,779 - Filed: 1993-05-20 - Granted: 1994-09-20 - Earliest claimed: 1992-05-20 - Assignees: Aloka Co., Ltd. - Inventors: Naoki Ohtomo; Shigeo Kimura - Web page: https://patentgrep.com/patent/US5348009A ## CPC - A61B 6/505: {for diagnosis of bone} - A61B 6/4417: {related to combined acquisition of different diagnostic modalities} - A61B 8/0875: {for diagnosis of bone} - A61B 8/4416: {related to combined acquisition of different diagnostic modalities, e.g. combination of ultrasound and X-ray acquisitions} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An apparatus for providing assessment indices related to bone strength which are useful in predicting the risk of bone fracture. The apparatus measures the mineral density of bone (BMD) by means of X-rays, while the propagation speed of sound V in the bone and bone thickness d are measured by means of ultrasonic waves. The bone mineral content per unit volume, i.e. the bone volume density .rho., is computed from the bone mineral density (BMD) and the thickness of the bone. An assessment value E is then computed based on V and .rho.. ## Claims ### Claim 1 A bone assessment apparatus comprising: means for measuring the propagation speed of sound in bone by passing ultrasonic waves through a test part of a subject's bone, means for measuring bone volume density by passing an X-ray beam of X-ray through said test part, and means for computing an assessment index for the bone based on said measured sound propagation speed and said measured bone volume density. ### Claim 2 (depends on 1) A bone assessment apparatus as defined in claim 1, wherein said propagation speed measuring means comprises: a pair of ultrasonic transducers for transmitting and receiving the ultrasonic waves through said test part, a thickness computer computing a thickness of the bone in a direction of the X-ray beam based on the waves received from said ultrasonic transducers, and a propagation speed computer computing the propagation speed of the ultrasonic waves by dividing an ultrasonic wave propagation time in the bone by said thickness; and wherein said bone volume density measuring means comprises: an X-ray generator for irradiating said test part with the X-rays, an X-ray detector for detecting the X-rays which have passed through said test part, and a density computer computing bone volume density based on an X-ray detection signal from said X-ray detector and said bone thickness. ### Claim 3 (depends on 2) A bone assessment apparatus as defined in claim 2, wherein said bone assessment index is the modulus of elasticity of the subject's bone. ### Claim 4 (depends on 2) A bone assessment apparatus as defined in claim 2, wherein said means for computing computes said bone assessment index based on a product of a square of said propagation speed of ultrasonic waves and said bone volume density. ### Claim 5 (depends on 2) A bone assessment apparatus as defined in claim 2 comprising a water tank for immersing said test part, and wherein said pair of ultrasonic transducers is disposed in said water tank. ### Claim 6 (depends on 5) A bone assessment apparatus as defined in claim 5, wherein said X-ray generator and said X-ray detector are outside said water tank. ### Claim 7 (depends on 6) A bone assessment apparatus as defined in claim 6 further comprising means for causing said pair of ultrasonic transducers, said X-ray generator and said X-ray detector to scan. ### Claim 8 (depends on 7) A bone assessment apparatus as defined in claim 7 further comprising a display connected to said assessment index computing means for displaying said bone assessment index. ### Claim 9 (depends on 8) A bone assessment apparatus as defined in claim 8 wherein said test part is the calcaneus. ### Claim 10 (depends on 2) A bone assessment apparatus as defined in claim 2 wherein said propagation speed measuring means measures the bone thickness by transmitting the ultrasonic waves through the subject's bone, and receiving the ultrasonic waves reflected from surfaces of the subject's bone. ### Claim 11 (depends on 2) A bone assessment apparatus as defined in claim 2 wherein said propagation speed measuring means measures the bone thickness by transmitting the ultrasonic waves from a direction perpendicular to the direction of the X-ray beam, and receiving the reflected ultrasonic waves. ### Claim 12 A bone assessment apparatus for computing bone assessment indices using ultrasonic waves and X-rays, comprising: a water tank having a region for receiving a subject, a pair of ultrasonic transducers, one transducer being disposed on each side of said region inside said water tank, an X-ray generator and X-ray detector, one of these units being disposed on each side of said region outside said water tank, and a pair of immersible bodies, one immersible body being disposed on each side of said region in a path of X-rays inside said water tank, wherein said immersible bodies contain at least one of a substance having a lower X-ray attenuation coefficient than water and a vacuum within a sealed interior, and means for computing an assessment index based on signals produced by said ultrasonic transducers and said X-ray detector. ### Claim 13 (depends on 12) A bone assessment apparatus as defined in claim 12 further comprising side walls, wherein said side walls enclose the X-ray path and consist of a member which obstructs X-rays. ### Claim 14 (depends on 13) A bone assessment apparatus as defined in claim 13 wherein each of said immersible bodies is a hollow member having a cylindrical form. ### Claim 15 (depends on 14) A bone assessment apparatus as defined in claim 14 comprising a scanning mechanism displacing said two immersible bodies, and said scanning mechanism displaces said immersible bodies as an X-ray measurement point moves while maintaining said bodies in the path of the X-rays.