Our Technology

Full-Field OCT

Full field OCT, the principle behind LLTech devices, performs non-invasive high-resolution optical slicing beneath the tissue surface.

The full field approach offers great potential in imaging of samples to assist fast diagnosis of cellular and morphological scale pathologies, such as cancer.
The schematic below illustrates the full-field OCT principle. It is essentially an interference microscope (i.e. a regular microscope with an added reference arm) or more precisely a classic Michelson interferometer with a microscope objective in each arm.

An incoherent light source illuminates the whole field of the microscope objectives. Due to the low temporal coherence of the source, interference occurs only when the optical path lengths of the two arms of the interferometer are identical within 1µm.
When a biological sample is placed under the microscope objective in the sample arm, the light reflected by the reference mirror interferes with the light reflected or backscattered by the sample structures contained in a limited volume. The Light-CT fine slicing ability allows depth exploration and high-quality 3D imaging.

For further details, scientific publications are available here.

Light-CT captures “en face” images directly using a megapixel camera and a pair of microscope objectives.
Light-CT derives from low coherence interference microscopy. The interferometer can be displaced to step the focal plane through different depths beneath the surface to create a 3D tomographic image. “En face” capture allows Light-CT to operate with high lateral resolution (typically ~1µm) using medium or large aperture microscope objectives.

The FFOCT image displays in gray scale the static optical contrast of the region of interest. Hihgly backscattering content like different fibrous structures (collagen, axons, etc.) appears white while weakly backscattering content like cells appears dark gray or black.

Dynamic Cell Imaging

Dynamic Cell Imaging (DCI) enhances the cellular contrast by capturing the residual microscopic intracellular movements in freshly excised tissue.

DCI images on breast tissue: (a) abnormal lobule in cancerous breast, (b) breast duct invaded by cancerous cells, (c) immune cells in inflammated breast.
Dynamic Cell Imaging provides a dynamic contrast at the intracellular scale which complements the morphological information provided by FFOCT, thus bringing LLTech images up to the histology level of detail and information richness.
As shown in the schematic below, the DCI technique consists in recording the time series of each voxel under examination during a few seconds and process them in order to extract characteristic features of the subcellular activity to be displayed. From a Fourier analysis of the time signal, the DCI RGB image is created where the blue channel corresponds to low frequency moving parts (< 0.5 Hz), the green channel displays medium frequency moving parts (0.5 to 5 Hz), and the red channel displays higher frequency moving parts (5 to 25 Hz). The signal intensity in each color channel reflects the dynamics amplitude in each corresponding frequency range.

The below DCI images obtained on different breast samples show the potential of the DCI technique to differentiate cancerous from normal tissue and ultimately to discriminate various cell types. Indeed, many bright yellow cells of particular shape are visible in image (c) whereas they do not appear in images (a) and (b). Also observed in liver and lymph node tissue DCI images, these cells are presumably immune cells and thus represent a good marker of inflammation.

See some clinical images here.

AI Analysis - Neural Networks

Light-CT Scanner will use AI to provide automated guidance.

LLTech collaborates with the best institutions (Institut Pasteur France) to develop AI algorithms that will analyse LLTech data. Preliminary results on a very small data exceed our expectations.

For further details, scientific publications are available here.

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