| 摘要 |
PURPOSE: To differentiate the tissues in the deep parts in a living body without executing enucleation even in the case of deep part from surface by forming a structure to diffuse part of the elastic wave energy to propagate the elastic waves generated in an electroacoustic converter into the examinee on the surface of a pricking needle. CONSTITUTION: A piezoelectric thin-film layer 10, comb-shaped electrodes 12 to 15 and a protective layer 16 are formed on the base part 11 of a needle-shaped probe 1. The elastic waves are generated in the piezoelectric thin-film layer 10 to propagate the elastic energy in the longitudinal direction of the needle when an ultrasonic pulse signal voltage having a prescribed central frequency is supplied to the set of pairs 12 and 13 of the comb-shaped electrodes. The elastic energy dissipates gradually to the tissues via the protective film 16 when the biotissues exist on the propagation route. This energy changes dependently upon the wavelengths of the elastic waves at which the energy dissipation quantity is generated when the average periodic structure of the biotissues varies. The frequency dependency of the insertion loss is, thereupon, detected when the frequency of the electric field to be impressed is changed. This characteristic reflects the periodic structure of the biotissues. The tissue differentiation is thus executed. |
