Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Patent
1997-07-23
1999-03-16
Lateef, Marvin M.
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
A61B 800
Patent
active
058823034
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a process according to the generic term of patent claim 1, an arrangement according to patent claim 7, a hammer unit according to the generic term of patent claim 9, a vibration absorption unit according to patent claim 11, an evaluation unit according to patent claim 12, and a control unit according to claim 13.
The rigidity, particularly the rigidity with respect to mechanical torsion of preferred beam or tube-like objects, can be determined relatively easily on the basis of their measurements and materials according to the laws of static. There are, however, certain cases wherein the measurements and/or the exact material composition and density cannot be determined, and the rigidity cannot be calculated. This is the case, on the one hand, in technical objects that cannot be separated or are very hard to separate from the surrounding material and, on the other hand, with live bones which are surrounded by (live) tissue.
The dispersion velocity and attenuation of mechanical waves in beam and tube-like objects stands in direct connection with their surface inertia momentum and with the electricity module of the object material. Based on Content by In Vivo Measurement of Flexural Wave Velocities," Medical & Fah et al., "Phase Velocity Measurement of Flexural Waves in Human Tibia," Journal of Biomechanics, Vol. 21, No. 11, pages 975-983, 1988, Great Britain, it is possible to determine the rigidity with respect to torsion by determining the phase velocity of flexural waves dispersing inside the object. The equations (1) and (2) as well as the second equation on page the phase velocities dependent upon the wave lengths. The rigidity of three-dimensional objects can be calculated from the transmission function of the mechanical waves dispersing within the object. This calculation is based, for example, on the models of Bernoulli-Euler, Pochhammer, and
If a force impulse is applied to the surface of the object, for example, a shin bone (tibia), then mechanic vibrations are excited within the object. Longitudinal vibrations as well as torsion and flexural vibrations and oscillations are excited and disperse into the ground mode and in higher modes in a beam or tube-like object (tibia). If the resistance to torsion of the shin bone (tibia) is to be determined, a hammer of a hammer unit is applied at about the height of the condyle of the shin bone in the direction of the main inertia axes, approximately vertical to the surface as represented in FIG. 1. The measurement of the excited flexural vibration occurs with the aid of at least two vibration absorption elements distanced from each other longitudinally along the object (tibia). So as to possibly measure only the flexural vibrations on the shin bone (tibia), the excitation point--attack point of the hammer--and both points for vibration measurement are placed in the medio-lateral plane of the diaphysis of the shin bone, that is, approximately parallel to the medial surface of the shin bone. In this configuration, the vibration absorption elements are sensitive only to the direction vertical to the bone surface. The phase velocities for the different flexural vibrations between the vibration absorption elements are determined by means of a numeric evaluation method. The rigidity with respect to torsion can be determined from the length of the beam or tube-like object, its diameter, and the phase velocity of a flexural wave at a certain frequency.
In the known process, a series of measurements must be carried out to obtain a reliable result of the determined wave dispersion properties.
The object of the invention is to determine the wave dispersion properties by means of a process that is fast and easy to apply.
The subject matter of the patent claims is directed toward attaining this object.
The process of the invention is particularly suitable for determining the wave dispersion properties in live bones or in beam or tube-shaped technical objects provided with a coating or imbedded in another material.
The process of the invention is us
REFERENCES:
patent: 4913157 (1990-04-01), Pratt, Jr. et al.
patent: 5143069 (1992-09-01), Kwon et al.
E. Stussi and D. Fah, "Assessment of bone mineral content by in vivo measurement of flexural wave velocities", Medical & Biological Engineering & Computing, 26 Jul. 1988, vol. 26, No. 4, pp. 349-354.
D. Fah and E. Stussi, "Phase velocity measurement of flexural waves in human tibia", Journal of Biomechanics, 5 Apr. 1988, vol. 21, no. 11, pp. 975-983.
Imam Ali
Lateef Marvin M.
LandOfFree
Process and arrangement for determining the dispersion propertie does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and arrangement for determining the dispersion propertie, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and arrangement for determining the dispersion propertie will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-812487