Measuring characteristics of living tissues by ultrasonic waves

Claim 3

A method according to claim 1 wherein the at least three frequencies f 1 , f 2 and f 3 form a geometric progression, i. e. in step A), and wherein a difference between the two differentiation equations obtained by step F) is obtained to obtain an attenuation inclination in step G).

Claim 4

A method according to claim 1 wherein the at least three frequencies f 1 , f 2 and f 3 form an arithmetic progression, i. e. f 1 - f 2 = f 2 - f 3 = . .. in step A), and wherein information on the frequency power exponent of the reflection coefficient is obtained in step G) by obtaining . a difference between the two differentiation equations obtained in step F).

Claim 5

. A method according to any one of claims 1 to 3 wherein at least four frequencies are transmitted; said measurement of a set of three frequencies of reflected waves is made; said measurement of another set of three frequencies of the reflected waves is made; said measurement of N sets of three frequencies of the reflected waves is made; and N measured results are subjected to statistical processing.

Claim 7

Apparatusfor measuring living tissue characteristics by transmitting ultrasonic waves into a living body and analyzing reflected waves therefrom, the apparatus comprising A) means for transmitting ultrasonic sound pressure waves of independent bands having at least three frequencies f 1 , f 2 and f 3 as their center frequencies, or of a wide band including such center frequencies; B) means for obtaining energies E 1 , E 2' E 3 (or amplitude absolute values Q 1 , Q 2 , Q 3 ) of the reflected waves of respective band components, by receiving the reflected waves by a receiving sen of for providing an output proportional to the sound pressure of the reflected waves, extracting respective band components and subjecting them to signal processing, or by receiving the reflected waves by a receiving sensor for providing an output proportional to the energy of reflected waves, extracting respective band components; C) means for taking logarithms lnE 1 , lnE2 and lnE 3 (or lnQ 1 , lnQ 2 and lnQ 3 ) of the energies (or the amplitude absolute values); D) means for obtaining a difference between two of the three logarithms; E) means for obtaining a difference between two logarithms of a combination different from that in means D); F)means for differentiating each of the differences as a function of a depth z of the living body in the direction of transmission of the ultrasonic waves; and G) means for obtaining an attenuation coefficient inclination and/or a space inclination of a frequency power exponent of a reflection coefficient from at least two differentiation equations obtained in the means F).

Claim 8

Apparatusfor measuring living tissue characteristics by transmitting ultrasonic waves into a living body and analyzing reflected waves therefrom, the apparatus comprising A) means for transmitting ultrasonic sound pressure waves of independent bands having at least three frequencies f 1 , f 2 and f 3 as their center frequencies, or of a wide band including such center frequencies; B) means for obtaining energies E 1 , E 2' E 3 (or amplitude absolute values Q 1 , Q 2 , Q 3 ) of the reflected waves of respective band components, by receiving the reflected waves by a receiving sen of for providing an output proportional to the sound pressure of the reflected waves, extracting respective band components and subjecting them to signal processing, or by receiving the reflected waves by a receiving sensor for providing an output proportional to the energy of reflected waves, extracting respective band components; C) means for taking logarithms lnE 1 , lnE2 and lnE 3 (or lnQ 1 , lnQ 2 and lnQ 3 ) of the energies (or the amplitude absolute values); D) means for obtaining a difference between two of the three logarithms; E) means for obtaining a difference between two logarithms of a combination different from that in means D); F)means for differentiating each of the differences as a function of a depth z of the living body in the direction of transmission of the ultrasonic waves; and G) means for obtaining an attenuation coefficient inclination and/or a space inclination of a frequency power exponent of a reflection coefficient from at least two differentiation equations obtained in the means F).

Claim 9

Apparatus according to claim 6 wherein the at least three frequencies f 1 , f 2 and f 3 form a geometric progression, i. e. in means A), and wherein a difference between the two differentiation equations obtained by meansF) is obtained to obtain an attenuation inclination in meansG).

Claim 10

Apparatus according to claim 6 wherein the at least three frequencies f 1 , f 2 and f 3 form an arithmetic progression, i. e. f l - f 2 = f 2 - f 3 = ... in means A), and wherein information on the frequency power exponent of the reflection coefficient is obtained by means G) by obtaining a difference between the two differentiation equations obtained by means F).

Claim 11

Apparatus according to any one of claims 6 to 8 wherein at least four frequencies are transmitted; measurement of a set of three frequencies of reflected waves is made; measurement of another set of three frequencies of the reflected waves is made; measurement of N sets of three frequencies of the reflected waves is made; and N measured results are subjected to statistical processing.

Claim 12

Apparatus according to any one of claims 6 to 9 wherein said measurement is made of a specified depth or/and M adjoining depths in the same direction of transmission and reception of the ultrasonic waves; and M measured values are subjected to statistical processing in means B) to G).