EU laser team readies cancer surgical strike

24 Apr 2008

Backed by industry and the European Commission, the 'Brighter' project is delivering powerful 635 and 650 nm diodes for medical applications as the first of its many goals.

"A laser-guided silver bullet to certain forms of cancer," is how Eric Larkins describes photodynamic therapy – the treatment in which cancer drugs are activated by light. Despite this powerful description, laser-activated photodynamic therapy (PDT) systems are limited by commercially available diode laser technologies, most of which were developed for CD players and telecom applications.

"The problem that doctors have is actually getting the wavelength and the powers that they need, as power is directly related to dosage," explained Larkins, the spokesperson for a multimillion euro research project called Brighter. Now, Brighter is promising to boost the effectiveness of PDT, with high-power 635 and 650 nm diodes primed for manufacture.

According to Larkins, Brighter's diodes will be integrated into delivery systems by project partner and leading PDT company Biolitec. The sheer extent of the overall €16.3 million ($26 million), 23 partner programme, which began in 2006, has enabled it to focus very closely on medical wavelength needs.

"In a project this size we can actually develop sources with wavelengths targeting specific photosensitizers, because we have the knowledge within the project,” Larkins said. “We're basically funding the associated research and development activity in terms of its marginal cost."

The diodes themselves are set to be sold by Eagleyard Photonics, a laser manufacturer spun-out of the Ferdinand-Braun-Institut für Höchstfrequenztechnik (FBH) Berlin, and by Osram Opto Semiconductors.

As well as PDT, Brighter is developing high-power, frequency-doubled light sources at 340 and 405 nm for medical fluorescence imaging, which will help doctors locate the tissue to be treated with PDT. Related systems have already been developed by the Risø National Laboratory at the Danish Technical University using 808 nm diodes and are being tested in Lund Laser Centre, Sweden. Although Brighter is only 16 months through its three-year schedule, these imaging systems are already in clinical trials.

The collaboration is using GaAs and InGaAsP materials for the fabrication of the fluorescence imaging diodes and InGaP for the PDT diodes. Larkins' team at the University of Nottingham, UK, is performing computational modeling with teams at the University of Cambridge, UK, and University Politecnica de Madrid, Spain. This will determine ideal laser designs for the project's frequency doubling and modulation schemes.

Brighter's principal goal is true to the project name – that is the development of particularly high-brightness lasers at its target wavelengths, with a focus on power, efficiency and beam quality.

For Osram, amongst other partners, the importance of this focus extends beyond medical uses, to laser projection display applications.

As well as the companies involved in PDT, the project's goals have also attracted other big names like Thales and Alcatel to the partnership, who are interested in high-power lasers for telecommunications purposes. Indeed, the programme's overall coordinator is Michel Krakowski of Alcatel-Thales III-V Labs.

These companies are amongst the eight industrial partners that have teamed with 15 academic institutions across Europe and helped top-up €9.7 million in European Commission funding to the €16.3 million figure.