3D Quantitative Analysis of Cancer Biosignatures
VisionGate’s innovative Cell-CT™ platform technology is breaking new ground in the field of quantitative cell analysis by virtue of its unique ability to compute the true 3D internal structure of cells based on molecular optical absorption densities and simultaneous optional fluorescence. The computed 3D density structure is isotropic within a cell; meaning the resolution is equal in all three spatial dimensions. Cells are not placed on slides, but rather, they are suspended in fluid and injected through a micro-capillary tube that permits 2D image collection around 360° that is utilized to compute the 3D image of the cell.
VisionGate’s method of 3D imaging uses state-of-the-art radiological x-ray CT tomographic image reconstruction, while utilizing visible photons rather than x-rays. The Cell-CT™ platform enables the quantitative analysis of the in situ 3D distribution of targeted molecular markers, stains and other absorbing structures within a cell at sub-micron resolution in a manner that links to traditional pathology, but with the third dimension as the new biosignature.
The true 3D structural anatomy of a biological cell has never before been seen. Most attempts to visualize cells in 3D are approximations derived through extremely cumbersome techniques. The anatomy of the cell has been elusive, and today’s 3D knowledge has been obtained indirectly. For the first time, VisionGate’s Cell-CT™ platform has allowed the visualization of the cell’s complex 3D anatomy, and this capability is leading to many important discoveries in the hands of leading scientists.
The Cell-CT™ Platform at work
VisionGate is concentrating its first efforts at the analysis of sputum samples. The sputum is processed prior to screening. A chemical fixative, an agent that stabilizes the cells and preserves them from decay, is added. Other steps include cleaning the specimen of debris, dissolving the mucus and staining the cells to highlight cellular features that are potentially indicative of cancer. The cells of interest are suspended in a fluid optimized for 3D optical imaging and injected into a capillary tube that is able to rotate axially as cells flow through it, allowing 360° viewing perspectives.
The Cell-CT™ platform uses pseudo-projection, an innovative technology in the way images are captured to allow them to simulate a standard parallel beam projection, as per an x-ray imaging device, to form a simulated projection image.
The Cell-CT™ platform consists of a standard Olympus IX71 microscope fitted with an oil-coupled 100x 1.3 NA objective to collect the pseudo-projection images in high resolution. A 2 Megapixel Prosilica GE1650 CCD camera with Gigabit Ethernet connectivity is mounted directly on the camera adapter port on the left side of the microscope to receive the pseudo-image feed.
The system uses a 50nm wide monochrome illumination in the green spectrum to highlight specific cell features.
The imaging process
The camera, rotation and lens scanning are synchronized to collect 500 pseudo-projection images per cell around 360° of rotation and at a rate of 5 images per second. The GigE camera is set to 12bit mode and operates at 1600x900 resolution. The 500 images are reconstructed using state-of-the-art computer tomography techniques to form a microscopic 3D representation of a stained cell. The resulting image can then be processed with appropriate analysis software to provide features of interest for a particular application.
VisionGate started commercializing the Cell-CT™ platform to research laboratories in the United States earlier this year. The device can be used to research any sample with cellular content that can be presented in suspension such as blood, cervical scrape, urine, etc. The company is specializing in lung diseases with a long term objective of providing physicians the means to detect cancers and lung conditions at an early stage in risk patients and to improve the survival rate and life expectancy.