image gallery

______________________________ Human Bronchus

______________________________ Human Pulmonary Parenchyma

______________________________ Other Human Tissues

______________________________ Pulmonary Stent

______________________________ Animal Tissues

technology

Overview

Since the early 1990s, there has been a growing recognition that optical interferometry can be applied to medicine for cross-sectional, or tomographic, imaging. The basis for this imaging method is that some near infrared (NIR) wavelengths can penetrate living tissues for very substantial distances. These wavelengths lie within the so-called "therapeutic window," which also allows for some light-based therapies.

      For a focused NIR light beam entering a tissue, it remains concentrated for its first few     millimeters of propagation before scattering causes the light to spread significantly. The      depth of penetration is the greatest for wavelengths that lie in the “therapeutic window.”

In light-based tomography, optical interferometry plays the role of optical ranging. Although optical interferometry had long been utilized in non-medical fields and known as Optical Coherence Domain Reflectometry (OCDR), not until recently did we see its first medical application in ophthalmology, a fruition of the pioneering work by J. G. Fujimoto et al. This modality has come to be known as Optical Coherence Tomography (OCT) in the arena of medical imaging.

An analogy can be drawn between OCT and ultrasound imaging in which the information carrier is sound waves instead of light. As the wavelength of the light is at least three orders of magnitude shorter than that of the sound wave, the imaging resolution of OCT is much higher, on the order of microns, making it ideal for the visualization of microanatomy and even cellular structures.

In order to realize the potentials of OCT in a broader medical field some technical hurdles remain to be overcome. The need for better image clarity, higher resolution and greater imaging depth has continued to push the boundaries of fiber optics, signal processing and computing algorithms. For endoscopic applications, the miniaturization of the optical probe poses an additional technical challenge.

Tomophase OCT Technology

Tomophase OCT imaging, or, TOCT, is a proprietary technology platform based on a series of innovations in fiber-optics, signal processing, computing algorithm and optical probe design. These innovations aim at providing more advanced imaging capabilities while suppressing the shortcomings of existing OCT technology.

  Tomophase tissue imaging system is composed of an imaging engine which is common to     many applications, a user interface and an appication specific optical probe or catheter.

The advantages and uniqueness of Tomophase technology stem, in part, from a proprietary optical imaging engine with an optical cross-correlator that circumvents the conventional optical interferometer. The Tomophase imagine engine possesses an unique self-cancellation mechanism for the rejection of common-mode noise generated by the light sources as well as the movement of the optical fibers. As a result, our imaging engine provides superior optical signal quality compared to the conventional technology.

This optical imaging engine, coupled with our proprietary signal processing algorithm, allows us to retrieve not only the first-order tomogram, as with the conventional OCT technology, but also high-order imageries including phase-resolved tomography and differential spectral-absorbance mapping in imaged cross-sections.

Still under development, phase contrast tomography (PCT) and spectral absorbance tomography (SAT) provide additional information pertinent to the physiological and metabolic activities of the living tissue under examination. Since pathological disorders often manifest themselves through abnormalities in one or more of the imaged properties, Tomophase imaging technology is a powerful tool for assessing the pathological nature of the tissues. This technique is analogous to satellite images of agricultural areas under visible, infrared, and UV light that assess crop yields, diseases, water stress, and other agricultural factors.

    The proprietary Tomophase imaging probe provides the flexibility of scanning the light     beam in either a forward-looking or a sideward-looking direction. Linked with the imaging        engine, one can acquire tomographic tissue images of tissues located in both areas.

A Tomophase tissue imaging system is complete with the addition of an application-specific ‘front-end’ catheter and a display device. A Tomophase proprietary design allows for the miniaturization of a highly flexible light delivery and collection catheter for imaging inside internal organs through the use of endoscopes. This miniature optical catheter can direct the NIR beam to scan in either a forward-looking or a sideward-looking direction. These two scan directions are switchable through lightwave control at the proximal end of the catheter system. This allows the user to easily assess tissues located in the front and to the side of the catheter with a single procedure.