Bimodal Photoacoustic / Optical Coherence Tomography (PAT/OCT) *
Photoacoustic Imaging (PAI) is a hybrid optical imaging modality which detects laser pulse induced ultrasonic waves. It can resolve the absorbers located in turbid media. Since the contrast is purely based on optical absorption, the imaging depth of PAI goes beyond the optical mean free path. Optical Coherence Tomography (OCT), on the other hand, uses scattering contrast. Based on low coherence interferometry, OCT is superb in resolving layered structures. An extension of OCT, namely OCT angiography (OCTA), can produce contrast based on speckle or phase variance. Combining OCT and PAI provides complementary tissue optical absorption, scattering information, and deep tissue structures. An imaging area of 15 mm × 15 mm can be achieved. This non-invasive, in vivo technology can be applied in both preclinical and clinical applications.
(a) OCT B-scan of skin over the dashed line in (b). (b) Photo of a surgical scar. (c) Depth color coded image of skin vasculature between 0.5 mm and 1 mm in z direction using acquired with bimodal OCTA/PAT imaging. (d) Depth color coded image of skin vasculature between 1 mm and 4 mm in z direction acquired with bimodal OCTA/PAT imaging. (e) Skin vasculature in gray scale between 0 mm and 0.5 mm in z direction imaged by OCTA. (f) Transition zone en face view showing the same vessels resolved by both OCTA (green) and PAT (red). (g) and (h) OCT/OCTA/PAT merged volume 3D rendering at two perspectives. Scale bar= 1 mm except in (a).OCT/PAT USE CASES
Use case | Node | DOI |
In vivo Zebrafish larva imaging | https://doi.org/10.1063/5.0059351https://doi.org/10.1364/boe.390410 | |
Human skin imaging | https://doi.org/10.1038/s41598-017-18331-9 https://doi.org/10.1364/boe.7.00339 https://doi.org/10.1364/BOE.6.003163 https://doi.org/10.1117/1.JBO.21.9.096011 |