Full-field optical coherence technology

CelTivity utilizes two proprietary technologies integrated within one exam producing high-resolution images that delineate tissue microstructures and intracellular activity up to 1µm in 3D.

Full-Field Optical Coherence Tomography

The CelTivity Full-Field OCT 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 diagnostic of cellular and morphological scale pathologies, such as cancer. It consists of an interference microscope, or more precisely, a classic Michelson interferometer with a microscope objective in each arm. The Michelson interferometer produces interference fringes by splitting a beam of light so that one beam strikes a fixed mirror and the other a movable mirror. When the reflected beams are brought back together an interference pattern results.

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 interferometer can be displaced to step the focal plane through different depths beneath the surface to create high-quality 3D tomographic images," adds Le Conte de Poly. "Light-CT captures, en face, images directly using a megapixel camera and a pair of microscope objectives with lateral resolution to typically ~1µm. The FFOCT image displays in gray scale the static optical contrast of the region of interest. Highly 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

The CelTivity DCI enhances the cellular contrast by capturing the residual microscopic intracellular movements in freshly excised tissue.

Dynamic Cell Imaging provides a dynamic contrast at the intracellular scale which complements the morphological information provided by FFOCT, thus bringing images up to the histology level of detail and information richness.

DCI technique consists of recording the time series of each voxel – a unit of graphic information that defines a point in three-dimensional space – 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 (<0.5Hz), the green channel displays medium frequency moving parts (0.5Hz to 5Hz), and the red channel displays higher frequency moving parts (5Hz to 25Hz). The signal intensity in each color channel reflects the dynamics amplitude in each corresponding frequency range.

"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," continues Le Conte de Poly.

© Aquyre Biosciences 

Dynamic cell imaging of cancerous breast tissue with two subtypes of cancer – nested cancer cells and isolated cancer cells in stroma.

Vibration Isolation

"Because CelTivity's technologies function at the micron level, vibration isolation is critical to maintaining the system's highest level of operation," explains Le Conte de Poly. "Footfall from someone walking by, the closing of doors, HVAC units operating, or elevators in motion create low frequency vibrations that can influence FFOCT and DCI imaging."

"Consequently, Celtivity is supported by vibration isolation designed to more thoroughly cancel out low-frequency vibrations," says Le Conte de Poly. "For this purpose Negative-Stiffness vibration isolation was selected because of its high performance capability, and ease of adaptability to hospital and laboratory environments."

Negative-Stiffness vibration isolation was developed by Minus K Technology, an OEM supplier to leading manufacturers of scanning probe microscopes, micro-hardness testers and other vibration-sensitive instruments and equipment. These vibration isolators are compact, and do not require electricity or compressed air, which enables sensitive instruments to be located wherever they are needed.  There are no motors, pumps or chambers, and no maintenance because there is nothing to wear out.  They operate purely in a passive mechanical mode.   

What is very advantageous about Negative-Stiffness isolators is that they achieve a high level of isolation in multiple directions.  These isolators have the flexibility of custom tailoring resonant frequencies to 0.5Hz* vertically and horizontally (with some versions at 1.5Hz horizontally). 

(*Note that for an isolation system with a 0.5Hz natural frequency, isolation begins at 0.7Hz and improves with increase in the vibration frequency.  The natural frequency is more commonly used to describe the system performance.)

Vertical-motion isolation is provided by a stiff spring that supports a weight load, combined with a Negative-Stiffness mechanism. The net vertical stiffness is made very low without affecting the static load-supporting capability of the spring. Beam-columns connected in series with the vertical-motion isolator provide horizontal-motion isolation.  A beam-column behaves as a spring combined with a negative-stiffness mechanism. The result is a compact passive isolator capable of very low vertical and horizontal natural frequencies and high internal structural frequencies.

© Minus K Technology 

Negative-Stiffness isolators deliver very high performance, as measured by a transmissibility curve. Vibration transmissibility is a measure of the vibrations that are transmitted through the isolator relative to the input vibrations. Negative-Stiffness isolators, when adjusted to 0.5Hz, achieve approximately 93% isolation efficiency at 2Hz; 99% at 5Hz; and 99.7% at 10Hz.

Better Image Quality

Celtivity's technology is the sole technique providing axial resolution of 1µm, which gives the highest quality image clarity and precision. It enables image capture on a 1cm² region of tissue in one minute, thereby enabling immediate quality control of biopsies.

 

Full-field optical coherence tomography and dynamic cell imaging produce real-time images showing tissue architecture and intracellular activity data without sample processing or staining, and no need for dyes, contrast agents or tissue freezing.