Use of a pulsed fibre laser as an excitation source for photoacoustic tomography.

The use of a pulsed fibre laser as an excitation source for photoacoustic tomography has been investigated. Fibre lasers have the advantage of being compact, robust and efficient compared to traditional excitation sources used for photoacoustic tomography (e. g. Q-switched Nd:YAG pumped OPO or dye systems). Their high pulse repetition frequencies and adjustable pulse duration, shape and duty cycle also enables a wide range of time and frequency domain excitation methods to be investigated. A 1060nm, 20W fibre laser was used to generate acoustic waves in a tissue mimicking phantom composed of blood filled tubes immersed in a 1% solution of intralipid (mu's=1mm(-1)). The laser was then combined with a Fabry Perot photoacoustic imaging system to obtain 3D images of a tissue mimicking phantom and an in vivo image of the vasculature of the palm of a volunteer. This study has demonstrated that pulsed fibre lasers have potential application as an excitation source for photoacoustic imaging of superficial blood vessels.