Nov 28, 2014
from 02:00 PM to 03:00 PM
|Where||Cavendish Laboratory, Small Lecture Theatre|
|Add event to calendar||
Biomedical photoacoustic imaging for the clinical and life sciences
Photoacoustic (PA) imaging is a new biomedical imaging modality based on the use of laser-generated ultrasound that has emerged over the last decade. It is a hybrid technique that combines the high contrast and spectroscopic-based specificity of optical imaging with the high spatial resolution available to ultrasound. In essence, a PA image can be regarded as an ultrasound image in which the contrast depends on optical absorption. As a consequence, it offers greater specificity than ultrasound with the ability to detect haemoglobin, lipids, water and other light-absorbing chromophores, but with higher penetration depth than purely optical imaging modalities such asmultiphoton microscopy that rely on ballistic photons. As well as visualizing anatomical structures such as the microvasculature, it can also provide functional information in the form of blood oxygenation, blood flow and temperature. All of this can be achieved over a range of length scales from microns to centimetres with scalable spatial resolution. These attributes lend PA imaging to a wide range of applications in clinical medicine, preclinical research and biology for studying cancer, cardiovascular disease, abnormalities of the microcirculation and other conditions. With the emergence of a variety of truly compelling in vivo images obtained by a number of groups around the world in the last 2–3 years, the technique has come of age and the promise of PA imaging is now beginning to be realized. This talk will describe the underlying physical principles of photoacoustic signal transduction and image reconstruction, a new type of photoacoustic scanner based upon optical ultrasound detection and a range of in vivo preclinical cancer imaging studies that exploit endogenous and genetically encoded contrast.