Rendering the invisible visible in real-time!

Product Announcement from Raytheon ELCAN Optical Technologies

Rendering the invisible visible in real-time!-Image

Rendering the invisible visible in real-time!

1 out of every 5 North Americans and 1 out of every 2 Australians will develop some form of skin cancer during their lifetime.

Surgical excision is the treatment of choice for most skin cancer. Melanoma, the most deadly form of skin cancer, is more likely to recur or metastasize if the diseased tissue is not completely removed. Current practice is to remove a margin of healthy tissue from around the melanoma, but the limiting factor is the Inability of the dermatological surgeon to differentiate between normal and cancerous tissue. This leaves the decision of how much extra tissue to excise to the surgeon's judgment. The recent development of a real-time visual method of detection can potentially assist in the appropriate removal of cancerous tissues.

Properties of light

Visible light is described in terms of three main characteristics: intensity, wavelength and polarization. Humans perceive intensity as brightness and wavelength as colour, but only have a marginal sensitivity to the polarization of light. Historically, medical imaging has mirrored human vision, exploiting only intensity and wavelength.

Light can be thought of as a wave, which vibrates in a plane perpendicular to the propagation direction. If the wave vibrations are all in one plane, the light is said to be linearly polarized. Many animals have polarization sensitive vision – first demonstrated in honeybees in the 1940s as a method of communication and navigation.

Many aquatic creatures also have visual systems that exploit the polarization of light. Cephalopods (cuttlefish, octopuses) are thought to compute difference signals in parallel from arrays of photo-receptors tuned to orthogonal polarizations, as an aid to find prey and as intra-species communication. They can detect an enhanced range of environmental signals by adding 'p-vision' to their sensory inputs.

Polarization difference imaging

When light is incident on particles such as tiny water droplets suspended in air or organelles within a cell, it scatters in many directions and reduces the visual contrast. This blurs the image and makes target detection difficult, if not impossible. Different scattering media result in different polarization parameters; polarization difference imaging (PDI) exploits these differences, leading to improved contrast in the image.

PDI improves visibility by amplifying the signal from targets with polarization difference magnitude distinct from the background. Real-time PDI (R-PDI) represents the intensity difference between an image captured at one polarization and the same image captured simultaneously at an orthogonal polarization.

James Plant, of Canadian firm Emergent Designs, applied for both US and Canadian patents for his method of deriving polarization difference imaging video and has a working prototype camera to achieve this. Based on his designs for R-PDI systems, many new applications have emerged.

R-PDI possesses the generally useful qualities of being passive, simple and potentially very fast. R-PDI can operate passively in any region of the electromagnetic spectrum. It is sensitive to intrinsically small signals and will detect an observed degree of linear polarization of less than 1%.

While natural light sources provide a degree of inherent polarization, the results of R-PDI can be enhanced using a light source matched to the planes of the imaging system.

Medical applications

Using current methodologies, histological examinations of excised tissue often reveal margins of malignant tissue left behind after surgery. This requires a subsequent, often more radical surgery. PDI can display the difference between cancer cells and normal cells. R-PDI will provide immediate results to the trained eye, allowing the surgeon to excise all of the diseased tissue during the first surgery.

PDI is also being combined with more conventional medical imaging processes. The sensitivity of detection for prostate cancer has been shown to increase when PDI is used in conjunction with fluorescence imaging and the microstructural changes indicative of degenerative joint disease and osteoarthritis can be exploited by combining PDI with optical coherence tomography.

The full implications of this breakthrough are still being discovered – and as it happens, ELCAN Optical Technologies will be there.

Company Profile:

ELCAN Optical Technologies is on the cutting-edge of optical and electronic technology for medical applications - setting new standards for patient care. ELCAN ( works with customers seeking to design new electro-optical systems in medical diagnostics, digital imaging and advanced sensing applications. We can provide complete end-to-end optical, electronic and electro-optical solutions to speed your idea to market. ELCAN's global procurement and contract manufacturing takes your idea from initial design and custom prototyping, through to cost-efficient high-volume production.

You have a vision. Let us show you the light.

For more information about how ELCAN can help make your concepts reality, contact:

Mia Nielsen, Medical Product Manager
705.528.7180 or