Abstract

Photoacoustic imaging is a new non invasive soft tissue imaging method in which low energy nanosecond pulses of visible or near infrared (NIR) laser light are used to excite subsurface ultrasound waves. The distinguishing advantage of the technique is that it provides both the spectroscopic based specificity of optical techniques and the high spatial resolution of ultrasound. Haemoglobin represents the most important source of endogenous contrast making the technique particularly well suited to imaging vascular structures. As well as providing anatomical images, quantitative physiological information can be obtained by imaging at multiple wavelengths and applying a spectroscopic analysis to determine the concentrations of specific endogenous chromophores such as oxy and deoxyhaemoglobin. These attributes make the technique well suited to studying a wide range of tissue abnormalities such as tumours and other pathologies characterised by changes in the structure and oxygenation status of the vasculature. A novel high resolution optical ultrasound imaging system has been developed and used to obtain 3D images of the superficial vascular anatomy of the mouse brain, skin and implanted tumours and demonstrate the quantitative spectroscopic capability of the technique.

© 2008 Optical Society of America