A new method called wavefront shaping optical coherence tomography (WS-OCT) enables in vivo deep tissue imaging of a mouse.

The collaborative research team of Professor YongKeun Park and Professor Yong Jeong in KI for Health Science and Technology (KIHST) demonstrated depth-enhanced imaging of a living mouse tissue using wavefront shaping optical coherence tomography (WS-OCT).

Optical coherence tomography (OCT) is a noninvasive imaging tool for biological tissues. Based on low coherence interferometry, the reflected signals from samples are utilized for reconstructing tomographic images of tissues. However, the optical inhomogeneity of tissues disturbs the light propagation, or light distribution, inside tissues. This multiple light scattering prevents deep tissue imaging, and a typical penetration depth is roughly limited to 1 mm.

Figure 1. Optical inhomogeneity in tissues causes multiple light scatterings in conventional OCT imaging. By controlling an incident wavefront, scattered waves can constructively interfere at the target depth to allow depth-enhanced OCT imaging.

The research team has developed a new method called wavefront shaping optical coherence tomography or WS-OCT. This method adjusts the light beam by using a micro-mirror array and effectively controls the multiple scattering in the spectral domain of OCT system. Compared with the conventional OCT imaging, WS-OCT technique can enhance the penetration depth up to 92%. The researchers also demonstrated that WS-OCT increases the penetration depth in a mouse tail imaging in vivo.

Because the wavefront shaping enhances the penetration depth in various types of tissues, WS-OCT system could eventually lead to in vivo deep tissue imaging for diagnostic purposes. This work was published online in Journal of Biomedical Optics in February 2016.

Figure 2. Histology shows the structure of the mouse tail tissue. The OCT image obtained with WS-OCT shows an enhanced penetration depth and image signals compared to the uncontrolled image.
Contact Information:
Park, YongKeun (Associate Professor, Department of Physics)
Jeong, Yong (Associate Professor, Department of Bio and Brain Engineering)
Homepage: http://bmol.kaist.ac.kr, http://ibrain.kaist.ac.kr
E-mail: yk.park@kaist.ac.kr, yong@kaist.ac.kr