Photonics technologies are everywhere but need a deft touch to integrate into light-based medical products.

Scott Wohlstein, The Photonics Group

Much like electronics is the study of the electron, photonics is the study of the photon and includes its generation/emission, transmission, detection and analysis. Incandescent/fluorescent light sources, UV lamps, lasers, LEDs, lenses, fiber optics, detectors and spectroscopy – they all fall under the photonics field.

Since the early 1960s, photonics technologies (such as lasers) have become progressively smaller, while overall performance has been improved, and can be found nearly everywhere. Once only theoretical, fiber lasers and laser-based headlights are now reality. Who would have thought a transistor which emitted light (LED), would ultimately replace the iconic and ubiquitous light bulb.

Best practices for integration and applications

Photonics technologies have a number of common issues with respect to successful integration into medical products:

• Mechanical – While most photonics devices require stable, stiff mounting, some are designed to transport light over flexible fiberoptics or articulated mirrors. Integrations which measure bioactive or birefringence typically have to be vibration isolated.
• Electrical – The first lasers had huge power supplies which could accommodate fluctuating power needs without affecting emission. Contemporary laser diodes and LEDs have fairly stringent power and stability requirements related to performance and lifecycle.
• Thermal – Photonics devices and systems perform better in cool and dry environments. Since the majority of “wallplug-to-emission” efficiency loss is due to heat, thermal considerations are not trivial. Cooling methods, physical location of sources and air circulation are all of major concern.
• Computational – Computer controlled power, interlocks and shutters can be complicated due to timing issues. A fast processor speed does not necessarily equate to fast response time in order to control emission.
• Material/chemical – Materials which break down under high heat (see thermal) or other cycling, may generate noxious gases and/or derate optical components by coating surfaces, de-bonding, etc.

Don’t forget: Standards and regulations may apply

The main regulations and standards which apply to lasers and LEDs follow:

• 21CFR1040.10/.11 – The US FDA Center for Devices and Radiological Health (CDRH), defines the Federal Laser Product Performance Standard (FLPPS or “flips”) within 21CFR1040.10/.11 and requires laser manufacturers to file a product report. While self-reporting, this is a federal law which you must comply with in order to manufacture and sell laser products in the US. As a manufacturer, you have to define your product under a specific laser class (independent of medical product class) and make sure your product meets the requirements (design, engineering controls, labeling and documentation) of your declared classification. Though the choice of process (paper, eSubmitter, or ESG), the FDA/CDRH has made the process easy.
• ANSI Z136 – The American National Standards Institute (ANSI) has developed the Z136 series of standards which encompass laser safety much like the EN60825 described below. ANSI Z136.1 (safe use of lasers) and Z136.3 (health care- which prescribes how medical-based laser products are used within the medical workplace) are most relevant.
• IEC EN60825 – The E.U .requires laser products to be compliant to the IEC EN60825 (Safety of laser products) series of standards, and while there are no filing requirements per se, proof of compliance to the standard is required. The completion of the manufacturer’s checklist (IEC TR60825-5) fulfills this requirement and is verified by testing.
• Harmonization – The FDA/CDRH has started the process of merging and purging the two systems together in an effort to bring the U.S. regulations up to par with technology and the rest of the world. The process is currently “in legal” with hopes to be completed within the next year or so. In the meantime, laser products manufactured and compliant to IEC EN60825 may be introduced into commerce under Laser Notice 50 – a document which stipulates which requirements are necessary and which are not in order to be accepted into the U.S. system.
• IEC EN62471 – Once part of EN60825, LEDs are now covered under EN62471 (“Photobiological safety of lamps and lamp Systems”). Its partner document IEC TR62471-2 (“Guidance on manufacturing requirements related to non-laser optical radiation safety”) assists LED manufacturers and those integrating LEDs into their products

Don’t step on that screw (or get a beam in the eye)

No other product type is more deserving of the old saying in the risk engineering profession: “Just because something is compliant, doesn’t mean it’s safe (and vice versa).” Shrewd product designers ensure their products are inherently safe and compliant with the appropriate standards and regulations.

The key to applying and integrating most regulated technologies is to start early – and the earlier the better. This is especially true with medical products incorporating photonics technologies which have their own dynamically complex series of regulations and standards with which to comply.

Scott Wohlstein is president of The Photonics Group (West Chester, Ohio), which he started in 1980. With his experience and formal education in photonics, he is a sought after expert in integration and application, and a known SME for light-based product safety. He has guided clients from initial start-up to global public companies in all markets and sits on a number of ANSI Z136 committees.

The opinions expressed in this blog post are the author’s only and do not necessarily reflect those of MedicalDesignandOutsourcing.com or its employees.