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Cancer imaging and phenotypic screening among strong implications linked to new tomography method

9/4/2020 9:27:50 AM Joseph Park, Illinois ECE

A study led by Xi Chen, a postdoctoral fellow in Holonyak Lab Professor Gabriel Popescu’s group, has been recently published in the high impact journal, Light: Science and Applications.

The proposed method, referred to as Wolf phase tomography, performs diffraction tomography using partially coherent fields to reveal the 3D distributions of refractive indices (RI) of transparent structures. The authors named the technique in honor of the late Emil Wolf, a pioneer in the field of optical coherence.

Sperm cells graphed.
WPT of sperm cells.

The real part of RI determines how light interacts with a medium in terms of scattering. For biological applications, the RI distribution highlycorrelates with cellular properties such as dry mass and chemical concentrations. Additionally, tissue RI can act as an intrinsic marker for cancer diagnosis through the revelation of nanoscale morphological changes in cells and tissues.

Xi Chen
Xi Chen

However, extracting the 3D RI distributions of transparent structures is not an easy task. The researchers' WPT method is nondestructive and not limited by the photobleaching and phototoxicity commonly associated with fluorescence microscopy. Furthermore, WPT preserves the diffraction-limited resolution of the microscope without introducing residual fringes and speckles.

The WPT reconstruction directly works in the space-time domain, without the need of a Fourier transformation, and decouples the refractive index distribution from the thickness of the sample. This method can open new avenues for medical applications including phenotypic screening, cellular monitoring, label-free cell classification, cancer histopathology, and 3D imaging of tumor microenvironments.

Image of neuron tomograph
Image of neuron tomograph.

Popescu is affiliated with both Illinois ECE and the Beckman Institute.

Their work is supported by the NSF, NIH, and NCI.

Read their publication here.