The body member positioning apparatus disclosed herein operates to clamp a body member, such as a foot, in relation to a fixture, e.g. such as may be used for ultrasonic bone testing. A shell member is provided which conforms to the expected shape of the body member with a space therebetween, this space being filled with a compliant foam liner. An inflatable bladder or bellows operates between a stationary housing part and a movable housing part to which the shell member is attached so that, by inflating the bladder, a clamping pressure can be exerted against a body member positioned between the shell and the fixture.
Osterporosis apparatus for measuring ultrasonic characteristic(s) of a patient's bone includes two ultrasonic transducers spacedly arranged in a respective head in the apparatus for ultrasonic transmission from one to the other; circuitry for controlling transmission from the one transducer, measuring the reception at the other and providing an output indicative of the ultrasonic characteristic(s), the apparatus including a fluid system having two diaphragms arranged in the respective heads so that there is a fluid path from each transducer to its diaphragm and a gap between the diaphragms which is occupied in use by the patient's bone.
In the ultrasonic bone testing apparatus disclosed herein, a pair of ultrasonic transducer assemblies are brought into contact with opposite sides of a patient's foot and each of the transducer assemblies includes, as an acoustic waveguide, a liquid filled bladder. The foot engaging end of each bladder is formed as a laterally projecting rounded cone so that, as the transducer assemblies are brought into contact with the foot, air is progressively and totally excluded from an enlarging area of contact. One or both of the transducer assemblies can be scanned with a small circular motion so that a variety of locations of the patient's foot can be sampled and the response can be analyzed.
An ultrasound bone analysis apparatus having locating means (14) such as a foot bed, for locating a patient's body part in a predetermined position, and a pair of ultrasonic transducers (20, 22) for use in taking ultrasonic measurements of the body part. Each transducer includes a body part contacting portion (19), such as a silicone pad, for ultrasonic contact with the body part. The apparatus further includes means for moving the body part contacting portion of each transducer relative to the body part for allowing the contact of each transducer with the body part to be more accurately controlled. The apparatus also includes pressure control means for controlling the pressure with which the body part contacting portion of the transducers contacts the body part. This allows the compression of the body part contacting portion to be maintained at a constant value and therefore for the measurements to be more accurate.
A method of calibrating an ultrasound bone analysis apparatus having a pair of transducer assemblies. Each transducer assembly has a transducer and a coupling pad, and is movable relative to the other so that a face of each pad can be moved to a position in which they mutually contact and to a position where the faces contact body parts. The method according to the present application includes transmitting an ultrasound signal from one transducer and receiving a signal corresponding to the transmitted ultrasound signal through the other transducer when the transducer assemblies are in the first position and the second position. A time for the ultrasound signal to pass through the body part is determined, and a width of the body part based on positions of the transducers is determined. Then, using the time and width values a speed of sound of the ultrasound signal passing through the body part with squish compensation is calculated.
An improvement to calibration and quality assurance of an ultrasonic bone analysis apparatus is achieved by using phantoms. A received ultrasound signal that passed through a first phantom is used as a baseline for calculating BUA. The first phantom has an attenuation-versus-frequency profile that is substantially flat in a frequency range of 200 to 1000 kHz and a sound impedance that approximates that of soft human tissue. A propagation time of the signal is used to calibrate a zero point of the apparatus. A second phantom has an attenuation in a frequency range of 200-1000 kHz which approximates that of a human foot, including an attenuation-versus-frequency profile that is substantially linear in the frequency range of 200-600 kHz and is approximately 1 dB/MHz per mm. A received ultrasound signal that passed through the second phantom is used to calibrate the apparatus for a BUA calculation, and can also be used for at least one of determining and correcting a drift of the apparatus. A third phantom has a predetermined SOS that is substantially independent of temperature. A received ultrasound signal that passed through the third phantom is used to calibrate the apparatus for a SOS calculation, and can also be used for at least one of determining and correcting instrument drift. An ultrasonic signal is transmitted through mutually touching transducer pads. The received signal is used as a baseline for calculating BUA. A measurement of the propagation time of the received signal is compared with a temporally-proximate measurement of an ultrasonic signal that passed through a patient's heel to determine a time of propagation through the heel.
