To provide a new measuring technique obtained by combining ultrasonic and light.
The light of a light source 10 irradiates an examinee 100 as equally as possible through an optical fiber 16. An echo sending oscillator 28a is driven with an internal reference signal of a first lock-in amplifier 30, and a reception signal obtained by an echo sound receiving oscillator 28b on an opposed side is synchronously detected by the internal reference signal to obtain a phase difference between both of them. At the time of chopping light irradiation to the examinee 100 by a light chopper 15, a sound velocity at each part of the examinee is varied by temperature variation by light absorption, an acoustic distance between the oscillators 28a and 28b is varied and the level of the phase difference output of the amplifier 30 is varied. At the time of detecting this variation in synchronization with the chopping of the chopper 15 by a second lock-in amplifier 34, the sound velocity variation of the examinee depending on the presence/absence of light irradiation is known. The perimeter of the examinee is scanned with ultrasonic beams and the reverse projection arithmetic of CT is applied to the sound velocity variation of each beam to obtain the tomographic image of the light absorption distribution of the examinee.
CHO YOSHIO
MATSUNAKA TOSHIYUKI
HOSOMI SHOHEI
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