Patent ID: 8607634

Claim:
A method for determining a size of an in vivo kidney stone, comprising the steps of: (a) using an in vivo device comprising an acoustic transducer to detect: (i) a first signal generated in response to an interrogation pulse, the first signal comprising a first reflected acoustic wave that is reflected from a proximal surface of the in vivo kidney stone and a second reflected acoustic wave that is reflected from a distal surface of the in vivo kidney stone; and (ii) a second signal generated in response to the interrogation pulse, the second signal comprising a reflected acoustic wave that is reflected from a tissue supporting the distal surface of the in vivo kidney stone and that is only passed through an acoustical path from the support tissue to the acoustic transducer, the acoustical path positioned through a material alongside and outside the in vivo kidney stone and distal of the proximal surface of the kidney stone, the material comprising a fluid or a tissue which has a different composition than the support tissue; and (b) processing the first and second signals to identify the first reflected acoustic wave and the acoustic wave reflected from the support tissue and processing the identified reflected acoustic waves to determine the size of the in vivo kidney stone, as a function of a time interval between the first reflected acoustic wave and the acoustic wave reflected from the support tissue and a speed of sound in the acoustical path material, and wherein the speed of sound in the acoustical path material is different than a speed of sound through the in vivo kidney stone.