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Abstract

The density of a discrete piece of hard tissue such as a bone in a patient may be determined by either of two methods. In a first method, an impulse of energy is introduced into the tissue, and the resulting vibration in the hard tissue is sensed and analyzed to compute the modal damping factor of the tissue, the modal damping factor being directly related to the density of the tissue. In a second method, a continuous energy input is introduced into the hard tissue. The resulting vibration in the tissue is measured with a mechano-electrical vibration transducer and a modal damping factor is calculated. The electro-mechanical vibration transducer of the preferred embodiment measures the pressure with which the transducer is pressed against the patient's flesh and only produces the continuous energy input when a predetermined pressure is achieved which is sufficient to prevent any significant vibration of the flesh surrounding the bone. Further, the transducer signals the user if too great a pressure is applied to the patient's flesh. An algorithm is used with a microprocessor to estimate the modal damping factor of the hard tissue by varying several parameters until the difference between the measured response of the hard tissue and a theoretical response is minimized.

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First Claim