illumiSonics Inc. - Photoacoustic Remote Sensing (PARS) microscopy
Similar to ultrasound imaging, traditional photoacoustic imaging systems require a coupling media, such as water or ultrasound gel, in between the ultrasound detector and the sample. This limits the use of these imaging systems in several clinical applications including wound healing, burn diagnostics, surgery, brain imaging, and many other endoscopic procedures where physical contact is impractical or undesirable as it may cause further damage or infection. There are also significant depth limitations to cellular-resolution, optically-focused, bio-microscopy which are hampering our ability to unravel cellular information at depths beyond ~1mm in living subjects. Development of a non-contact deep cellular-resolution PA is essential for many clinical and pre-clinical applications.
We recently pioneered a new technique (Photoacoustic Remote Sensing - PARS®) that allows photoacoustic imaging without the need for any coupling media. This technique uses all-optical detection to remotely detect the photoacoustic signals through air and is capable of providing real-time imaging with cellular resolution. To achieve this, we use two laser beams at different wavelengths. One is visible light used to generate the signal, while the other is near-infrared invisible light used to detect the signal. The energy of these beams are very low and not harmful to tissue. PARS® can provide breath-taking images of blood vessels down to the capillary level and can even visualize individual red blood cells in real-time.
PARS® is also capable of visualizing physiologically important parameters such as the oxygen saturation of blood vessels and can be used to distinguish arteries and veins. This is important for various disease including cancer, diabetes, and ischemia. We believe that this technology will have significant impact in visualizing and understanding cancer biology, as well, impacting dermatological application and even enabling functional brain imaging.