MEDICA TECH FORUM: light-based imaging technique OCT

Since its inception, MEDICA TECH FORUM has focused on the implementation of innovations and new technologies into clinical practice. 2019 marks the tenth year of the Forum. In honor of its anniversary, we will brighten things up a bit, as one of the focal points will highlight how optical coherence tomography (OCT) uses light to produce images.

Enno Hachgenei sat down with MEDICA-tradefair.com and talked about imaging with OCT, described its applications in the medical field and explained how it can inspire the creation of new medical devices.

Mr. Hachgenei, what is Optical Coherence Tomography?

Enno Hachgenei: Optical coherence tomography (OCT) is an optical imaging technique that creates high-resolution cross-sectional images of biological samples and tissue. People often draw an analogy between OCT and ultrasound. Ultrasound measures and displays the transmission of short pulses of ultrasound energy into tissue and the reflection of signals. The OCT mechanism is similar, only OCT uses the reflection of light.

How does it work exactly?

Hachgenei: We direct near-infrared light into the tissue. The light is reflected at the boundary layers and tissue structures and back-scatters. This backscattered signal allows you to obtain a depth profile. OCT has millimeter depth of penetration, depending on the optical properties of the tissue and up to single-digit micrometer resolution.

The absorption of the used wavelength by the tissue and the scattering behavior are critical for the illustration. Generally, for tomographic imaging purposes, OCT can only be applied with tissue that’s transparent or semi-transparent for the wavelength used.

What are its applications in the medical field?

Hachgenei: OCT originates in ophthalmology. It is the perfect method in this setting since you can achieve deeper penetration via the eye's vitreous humor, making it a great way to capture details of the cornea and retina. OCT is mainly used for the early diagnosis of various eye conditions, such as diabetic retinopathy and age-related macular degeneration.

Are there other fields of application?

Hachgenei: There are already several areas of application in gastroenterology, dermatology and cardiovascular imaging. However, OCT is not a standard procedure in this setting and applied on a case-by-case basis.

For many years, the Fraunhofer IPT has explored possible fields of application and cases where OCT can be especially helpful. One area that receives expansive research funding – not just in Germany but worldwide - pertains to the detection and diagnosis of cancer. Thanks to imaging depth and high-resolution, OCT is a great technique to differentiate tissue types and to detect tumor locations and show healthy tissue. In recent years, we have also seen attempts to combine tissue diagnostics and identification with artificial intelligence.

Does the actual technology have to be improved to yield more applications?

Hachgenei: OCT is already well-developed and features many functional enhancements to the existing technology, thus offering many great benefits to applications in the medical field. This does not necessitate technological advances, albeit there is always room for improvement of course.

You will be one of the speakers on this topic at the MEDICA TECH FORUM. What areas will you focus on?

Hachgenei: We must identify and extensively research potential uses and future applications of OCT technology, aimed at developing new medical devices. I will mostly highlight the paths that the Fraunhofer IPT pursues in this setting. To this end, we have built two networks - a national research network (Innovations-Hub FOMed) and a German-Japanese research alliance (OCTmapp) to team up clinicians, systems integrators, component manufacturers and other researchers. I will showcase these pursuits at MEDICA.