MINERVA – MId-to-NEaR infrared spectroscopy for improVed medical diAgnostics
Image of prostate tissue using mid-IR. [Courtesy of University of Exeter]
MINERVA is a European Commission funded project that aims to develop photonic technology in the mid-IR to improve early cancer detection. The project is named after the Roman goddess of medicine and wisdom and is derived from the acronym “MId-to-NEaR infrared spectroscopy for improVed medical diAgnostics”.
The near infrared (nearIR) covers wavelengths from just pass the red end of the visible at 0.75 microns to 3 microns and mid-infrared (midIR) extends from 3 microns to 10 microns. The midIR covers the so-called “fingerprint region”, where organic molecules all have complex absorption spectra based on their various vibration and rotation modes. These allow the accurate identification of many fundamental bio-molecules such as fats, proteins and carbohydrates that can provide important new information which may be used for disease diagnosis.
Traditional methods of cancer diagnosis depend upon microscopic analysis of cell samples. With even the most powerful microscopes human judgment is an essential part of the process. This introduces subjectivity and room for error into the diagnostic system (even experts often disagree). Results become more reliable as the cancer progresses, but this increase in reliability has to be off-set against the reduction in effectiveness resultant from the delay. Furthermore, invasive surgery of some level is usually necessary to obtain the sample, even if this sample is to test the skin.
Molecular diagnostics of cell samples using amplification and detection of genetic material has emerged as a very sensitive medical test to detect disease. However without the expert discrimination provided by imaging cellular structure the pure molecular techniques have often proved to not be very specific to a particular disease and have had difficulty being qualified.
Mid-IR imaging spectroscopy has the potential to span the gap between imaging and molecular diagnostics and offer significant advances in both the effectiveness and efficiency of bio-medical imaging. It potentially can therefore be and effective tool for early cancer diagnosis and consequentially improved survival rates. Rather than a search for simple “cancer marker” absorption peaks, great progress has been made by analyzing the entire bimolecular mid-IR spectral signature using automated algorithms. To date however, the lack of suitable sources, detectors and components has restricted the technology to one of mainly academic interest, based on weak thermal sources and low power lasers or expensive synchrotron research tools. However, the photonic technology is now in place to develop a new mid-IR technology platform on which entirely novel supercontinuum sources (c.1000x brighter than thermal sources) covering the whole range from 1.5 to 12 µm are feasible. MINERVA seeks to develop new supercontinuum sources together with their associated pump lasers, and to combine them with new cameras and ancillary components including optical filters in an integrated system. The project will target two specific applications: in vivo identification of skin cancer with a rigid probe, and microscope-based in vitro assessment of patient samples. In the longer term the technology could be extended to many other diagnostic applications, including endoscopic variants and it is expected that there will also be spin-off applications for the mid-IR technology in other medical and industrial fields.
The MINERVA consortium is relatively large, comprising thirteen members, each of whom brings their own expertise to the project, whether this is in the field of hardware, software or application. Gooch & Housego is acting as technical coordinator as well as developing individual components. Both G&H (UK) in Ilminster and G&H (Torquay) are participating in the MINERVA project. New fiber components will require novel fabrication and handling techniques. Work is well underway in developing techniques that can be used effectively with the new generation of non-silica optical fiber. G&H MINERVA components will include fused couplers, tapers and tunable filters. Other partners will develop the mid-IR fibers, optical materials, detectors, pump sources at 2.9 and 4.5 µm and various supercontinuum sources.
Gooch & Housego (UK) is responsible for bringing all of the separate parts of the project together and integrating them into a single instrument. This includes the software, not only for control of the instrument and its functions but also for the processing of the results. MINERVA will also work to identify combinations of spectral features that characterize the presence of the tumors in question.
The other individual partners of the MINERVA consortium are: NKT Photonics (Denmark); LISA Laser (Germany); BBT-Materials (Czech Republic); Xenics (Belgium); IR Nova (Sweden); University of Nottingham (UK); Technical University of Denmark; Vivid Components (Germany); Westfaelische Wilhelms-Universitaet (Germany); Gloucestershire Hospitals NHS Foundation Trust (UK); The University of Exeter (UK) & Universidad Politecnica de Valencia (Spain).