Evaluation of an optical fibre probe for in vivo measurement of the photoacoustic response of tissues

摘要

A miniature (I mm diameter) all-optical photoacoustic probe for generating and detecting ultrasonic thermoplastic waves in biological media at the tip of an optical fibre has been developed The pre be provides a compact and convenient means of performing pulsed photoacoustie spectroscopy for the characterisation of biological tissue The device is based upon a transparent Faber Perot polymer film ultrasound sensor mounted directly over the end of a multimode optical fibre The optical fibre is used to deliver nanosecond laser pulses to the tissue producing thermoelastic waves which are then detected by the sensor. Detection sensitivities of 53mv/MPa and a 10kPa acoustic noise floor have been demonstrated giving excellent .signal to noise ratios in a strong liquid absorber Lower, but clearly detectable, signals in post mortem human aorta have also been observed The performance and small physical size of the device suggest that it has the potential to perform remote in situ photoacoustic measurements in tissue.