Light imaging technologies offer diagnostic potential

Firms vie for position in OCT and fluorescence

Light-based imaging technologies are beginning to make progress on the long path to commercialization. Systems employing one such approach, optical coherence tomography (OCT), have already been deployed for use in ophthalmic applications. Meanwhile, another light imaging technique, autoflourescence, has been temporarily stymied due to legal action between the technology developer and its marketing partner.

One company moving its technology closer to market is Coherent Diagnostic Technology (CDT), which has licensed patents for the use of OCT from MIT (SCAN 11/11/98). The vendor hopes to have its first product on the market within nine months, according to Paul A. Magnin, president and CEO. Magnin, who holds five patents in ultrasound, moved to CDT last year from his position as general manager of imaging systems at Hewlett Packard.

CDT’s first product will not be a medical in-vivo imaging device but rather a microscopy system, which does not require review by the Food and Drug Administration, he said. The company already has a large order for the OCT microscopy product.

CDT moved into a larger facility in Westford, MA, in July and has been hiring additional personnel, Magnin said. The extra space will be used both to produce the microscopy product and to continue development of medical applications of OCT, such as gastrointestinal and intravascular imaging. These applications are still a couple of years away from commercialization. German optics vendor Carl Zeiss holds a minority stake in CDT and will distribute the microscopy system, Magnin said. CDT is in discussions with a number of large vendors worldwide for licensing agreements and marketing relationships in medical imaging applications of the OCT technology. A medical imaging partner could potentially assist with product development and regulatory clearance for some OCT applications.

Zeiss is already a pioneer in commercializing OCT technology through its wholly owned Zeiss Humphrey Systems subsidiary in Dublin, CA, which, like CDT, licenses the OCT technology from MIT. Zeiss Humphrey is using the technology in ophthalmic applications. The vendor has sold about 200 OCT devices for use in imaging the retina since receiving FDA clearance two years ago, according to Lothar Koob, president.

Zeiss Humphrey’s OCT device enables physicians to look inside the retina in order to better determine signs of such maladies as macular degeneration and glaucoma, he said. Previously, cameras could look only at the surface of the retina.

“This allows doctors to look at the different layers of the retina,” Koob said. “There are various diseases that manifest themselves in those layers or in the degeneration or separation of those layers.”

The fact that this new industry is drawing senior medical imaging personnel is one indication of the perceived high potential of OCT technology. Koob came to Zeiss Humphrey last year from his position as Siemens group vice president of ultrasound.

Another OCT effort may be taking more substantive form in the U.S. shortly. OCTI of Cleveland was formed to further technology developed in Russia (SCAN 9/16/98). So far, however, the U.S. company has been solely a legal entity set up to hold the Russian technology, according to Warren Goldenberg, a partner with OCTI’s law firm, Hahn, Loeser, and Parks of Cleveland.

An actual company with a facility and employees could be on hand as early as the end of this year, Goldenberg said. Along with related Russian technical institutes, Russian inventors of this OCT technology have developed a prototype system, which has been tested on several hundred patients in Russia, Germany, and France, he said. Talks are in the final stages for the development of a testing relationship with a large U.S. institution, perhaps to be finalized within the next two months.

There will likely be some dispute as to patent rights and the need for licensing, however. CDT believes that MIT’s patents are the most fundamental of those dealing with OCT technology, Magnin said.

Infrared light wavesInterferometry techniques are used in OCT to measure the reflection of infrared light waves in a manner analogous to ultrasound’s use of sound waves. OCT is similar to other medical imaging modalities in that it creates a cross-sectional image of tissue within the body. It is different in that it can image only to a depth of about 4 mm and focuses on obtaining very high resolution images with small fields of view, according to Philip Drew, a principal at Concord, MA-based Concord Consulting Group.

CDT, for instance, is looking to place OCT devices on the end of a catheter or an endoscope for use within vessels and body cavities and on hand-held devices for surgical applications. OCT’s high resolution and tissue penetration capabilities offer the potential to more effectively guide therapies than do existing intravascular ultrasound and endoscopic techniques, Magnin said.

“Because the resolution is higher, we hope to be able to differentiate between vulnerable plaques and more stable calcified plaques (in intravascular clinical trials),” he said.

Because it can image to the cellular level, OCT may also potentially distinguish between normal and cancerous cells, Drew said.

“The question remains whether you can reliably recognize the difference between a normal cell and a malignant cell on the basis of this cross sectional image formed using light,” he said. “However, OCT opens a totally new avenue (in imaging) that has never been explored before.”

Another light-imaging technology that has shown utility in differentiating malignant from normal tissue is autofluorescence imaging. Autofluorescence is based on the fact that tissues fluoresce when exposed to light and that cancerous tissue fluoresces differently than normal tissue, according to Drew.

Unfortunately, the only commercial effort in this field was halted in August by a patent dispute. Canadian developer Xillix of Richmond, BC, laid off about 80% of its staff as it prepared to enter arbitration with its development and marketing partner, Olympus Optical of Japan. Xillix says Olympus secretly patented competitive technology produced through their joint development effort.

Xillix has installed 130 of its dedicated LIFE lung fluorescence endoscopy systems worldwide, with the marketing assistance of Olympus, which controls about 70% of the world endoscopy market. The two firms had been close to entering clinical trials on a combination endoscope using both standard white light and fluorescence technology in GI applications.

Now, all Xillix sales have been halted until the patent dispute is settled, said Pierre Leduc, president. The company does intend to search for partners looking to develop this technology in new applications.

“The shame in all of this is that here is a breakthrough technology in the area of cancer detection that is not going to be available,” Leduc said. “Our clinical trials showed a 171% improvement over white light in detecting early cancer.”