Optical chips are looking under your skin?

Is the 21st century the era of photonics? Photonic technologies such as optical chips can revolutionize our future since they have many applications not only in the field of telecommunications but also in healthcare and life science, security, lighting and displays. Here is an interesting story about how optical chips can be considered as a way to improve healthcare systems and more specifically increasing the chance for skin cancer curing by aiding early detection.

An example of nodular BBC lesion and its OCT image. The image in between shows where the OCT scan was performed. Credit: M. Mogensen et al 2009 (5).

An example of nodular BBC lesion and its OCT image. The image in between shows where the OCT scan was performed. Credit: M. Mogensen et al 2009 (5).

We acted on our dreams of improvement of our lives over thousand years ago when humankind started to create and control fire. Since then pursuing the mystery of light and mastering it has been a goal for providing significant developments in our daily life (1).

Miniaturization of optical components and integrating them on a single chip is a technology which provides advanced photonic devices (2). Such photonic devices based on optical chips reduce system size, power consumption, and potentially the cost, and increase reliability; that’s why the US recently launched the $610M Integrated Photonics Initiative (3). Such chips should be able to satisfy the strong desire for compact, low cost and miniaturized diagnostic imaging technologies for healthcare.

Among a variety of imaging techniques optical coherence tomography (OCT) is a real-time, label-free, and non-invasive one which can be used for diagnosis of diseases such as non-melanoma skin cancer. This imaging technology allows us to look 1-2 mm deep underneath the skin to see tumors (4). Figure above shows an example of nodular BBC, which are abnormal, uncontrolled growth or lesions that arise in the skin basal cells, which line the deepest layer of the epidermis (6),  lesion and its OCT image where we can see the difference between normal skin and BCC lesion (5). In fact, 1.3 million patients a year are affected by this cancer which is the most common form of cancer in the western world (5). Therefore, finding a solution for early diagnosis of skin cancer is crucial, as it improves treatment and rates of survival.

Using optical chips for skin imaging provides a potentially compact, turnkey solution for early detection of skin cancer which can, for example, be built into wearable devices. An example of photonic integration for OCT is shown in the figure below in which one of the OCT components, namely the interferometer, is integrated. This Mach-Zehnder interferometer based optical chip can be used for in vivo OCT images of human skin. The integrated interferometer chip size that is used in this OCT set up was only  which completely replaces the interferometer in a spectrometer based OCT system (4).

(a) Schematic layout of the OCT setup (b) Photograph of OCT setup. Credit: Yurtsever et al. 2014 (4).

(a) Schematic layout of the OCT setup (b) Photograph of OCT setup. Credit: Yurtsever et al. 2014 (4).

The benefit of using a compact OCT system for patients would be a faster treatment in a dermatology clinic, with immediate feedback of the results of the diagnosis (7). Optical chips could make a contribution to this technology by reducing cost and size of such systems even further. Integration of all optical components on a single chip (8) paves the way toward OCT to be used as a portable device.

In my opinion, the portability and compactness of this integrated device could be a big step towards providing suitable healthcare strategies for everyone. It can provide not only individuals in remote areas, without easy access to doctors and hospitals with early skin cancer detection. But also, in our aging society, many will prefer, or are forced, to keep track of their health at home.

So, this century will indeed see a huge impact of photonics, for example in the field of healthcare, as I discussed here. Photonics does not only change the techniques and the quality of our healthcare but by providing cheap, miniaturized chip-based systems, it will change the way how our healthcare system works too.

More Information

1 – J. Niehoff, T. P. Pearsall, “Consolidated European Photonics Research Initiative, Photonics for the 21st century,” VDI- The Association of German Engineers.
2 – G. Lifante, “Integrated Photonics: Fundamentals,” John Wiley & Sons Ltd, 2003.
3 –  https://www.dodmantech.com/Institutes/IPIMI
4 – G. Yurtsever, B. Považay, A. Alex, B. Zabihian, W. Drexler, and R. Baets . “Photonic integrated Mach-Zehnder interferometer with an on-chip reference arm for optical coherence tomography,” Biomedical Optics Express, March 2014.
5 – M. Mogensen, M. Mogensen, L. Thrane, T. M. Joergensen, P. E. Andersen, and G. B. E. Jemec, “Optical coherence tomography for imaging of skin and skin diseases”, Seminar in Cutaneous Medicine & Surgery, 2009.
6 – http://www.skincancer.org/skin-cancer-information/basal-cell-carcinoma
7 – M. Boone, “New imaging technology that gets under the skin,” Dermatology and Allergy Private Practice, Meise, Belgium. 2011
8 – https://light2015blog.org/2015/02/03/photonic-integrated-circuits-the-impact-of-an-exponentially-growing-technology/

PhotoHakimeh Mohammadhosseini is a PhD student in the Department of Engineering of Aarhus University where she is working in a project on fully integrated silicon photonics based transceivers to enable the required growth of wireless networks over the next decade. She received a B.Sc. degree in solid state physics from Islamic Azad University and a M.Sc. degree in photonics from Iran University of Science and Technology, in 2009 and 2013, respectively.



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