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By shrinking the core technology of optical coherence tomography to the size of a coin-and reducing its cost-a team of European scientists hopes to improve early diagnosis and screening of retinal diseases.
Reviewed by Prof. Wolfgang Drexler
Vienna-A consortium of European experts in academia and industry is collaborating on an ambitious, 4-year project to shrink both the size and cost of optical coherence tomography (OCT) systems.
The OCTChip (ophthalmic OCT on a chip) project aims to use photonic integrated circuits to produce a coin-sized, retinal scanner that will improve the screening and diagnosis of retinal diseases, such as age-related macular degeneration, diabetic retinopathy, and glaucoma.
Wolfgang Drexler, professor of medical physics, head of the Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, is leading the project, which began at the start of 2016. Less than a year in, his team has come up with preliminary designs and ideas for packaging.
“I’m quite positive that in 1 year or so we’ll have the first prototype, and then in 2 or 3 years we will go into clinical trials with an improved prototype,” Prof. Drexler said.
Commercialization and mass production could be achieved by 2020.
“It’s something that will revolutionize the biomedical or bio-optical imaging world because it can be made very compact and it is maintenance-free,” Prof. Drexler added.
The chip will be packaged in a format that could be handheld or maneuvered in front of a patient’s eyes, perhaps resembling a larger laser pointer. This could broaden the spectrum of patients who could more readily undergo imaging, such as premature infants or elderly patients who have difficulty traveling to medical facilities.
Such a compact tool scanner could also be easily transported to developing or remote areas of the world where electricity is scarce, with images conveyed to a reading center via a wireless or Bluetooth connection using a cellphone or tablet. This arrangement would also allow for rapid feedback and open a pathway to quicker diagnosis and treatment.
The research and development team is also envisioning that an extremely compact OCT system could one day be on store shelves as a consumer product for self-diagnosis of retinal or dermatologic diseases, Prof. Drexler said.
The miniaturized OCT system would represent a significant leap in OCT technology. OCT is now 25 years old and reigns as the gold standard in the diagnosis of eye diseases, as well as being used in such specialties as cardiology and gastroenterology.
But according to Prof. Drexler, despite steady improvement in OCT technology over the years, miniaturization has never been a priority as it has been in fields, such as consumer electronics, where tablets and mobile phones have supplanted desktop computers for many users.
In addition, the bulk and cost of current OCT systems have limited their use to facilities and practitioners that could afford them and support the technology.
Prof. Drexler was already thinking about how to transfer the optical set-up of OCT to a chip a decade ago and began collaborating with academic experts who were working on photonic integrated circuits in telecommunications. One of the thornier problems they had to solve was how to minimize optical losses when transferring optical imaging technology to a chip, since high optical losses are common in telecommunications.
Prof. Drexler subsequently initiated not only the OCTChip project that he now heads but another for dermatologic OCT on a chip, which has now been commercialized for cancer diagnosis.
The novel approach the OCTChip team of scientists and engineers is using to ensure superior optical quality while shrinking the core OCT technology is the use of photonic integrated circuits.
“By using photonic integrated circuits we can combine planar optical waveguides, and we also use microelectronics packaged on these chips so that it’s extremely compact and low cost and hopefully even higher performing than recent commercial OCT systems,” Prof. Drexler said.
He added that the use of integrated optics and electronics provides a significant manufacturing scalability advantage arising from the micro-fabrication processes, the proposed silicon-based platform.
OCTChip is funded by the Photonics Public Private Partnership (Photonics PPP); the project has received nearly EUR 4 million so far this year. Photonics 21 is a technology platform bringing together professionals and industries in photonics to develop strategies for research and innovation in Europe.
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“What I like about this initiative is that you can really put together the expertise that you normally don’t have in your lab, and by putting it together you can really do stunning things,” Prof. Drexler said.
Participants in the OCTChip project include the Medical University of Vienna, which is coordinating the effort, University College Cork in Ireland, the Austrian Institute of Technology, the Fraunhofer Network in Germany, Carl Zeiss, Austrian sensor firm AMS, and the Swiss company Exalos AG.
Prof. Wolfgang Drexler
Prof. Drexler is a consultant for Carl Zeiss Meditec as well as Exalos regarding OCTChip and the topic it covers.