Functional and Molecular Photoacoustic Computed Tomography Using Light Emitting Diodes

Photoacoustic Computed Tomography (PACT) has been widely explored for inexpensive non-ionizing functional and molecular imaging of small animals and humans. In order for light to penetrate into deep tissue, a bulky and high-cost tunable laser is typically employed. Light Emitting Diodes (LEDs) have recently emerged as smaller and cost-effective alternative illumination sources for photoacoustic (PA) imaging. We recently developed a portable, low-cost multispectral three-dimensional PACT system using multi-wavelength LED arrays, referred to as LED-PACT, enabling similar functional and molecular imaging capabilities as standard tunable lasers. In this chapter, first the capabilities of commercial LED array-based B-mode PA and Ultrasound (US) imaging system, referred to as LED-PAUS, to perform functional and molecular imaging with both in vivo and phantoms studies are presented. We also present the details of the development of LED-PACT system with essential hardware components, acquisition and reconstruction software needed for the implementation. This chapter also covers simulations and experimental results comparing the capabilities of LED-PACT system with commercial LED-PAUS system. LED-PACT and LED-PAUS system together demonstrate the potential of LED based photoacoustic imaging for pre-clinical and clinical applications.