Exploring the Body Using Light
There is an increasing demand by medical providers and their patients for diagnostic and monitoring tests which are rapid, inexpensive, non-invasive, are portable, do not require major infrastructure, are suitable for use with infants through to the elderly and require minimal technical training for the operating staff.
Near infrared or NIR spectroscopy offers these advantages and is on the verge of entering everyday clinical use. The current special issue of JNIRS—Journal of Near Infrared Spectroscopy is essential reading on this subject for medical technologists as it contains 16 papers, of which 13 are major reviews, providing an up-to-date overview of the field (http://www.impublications.com/content/jnirs-table-contents?issue=20_1).
The topics covered include the theory of how light interacts with tissues in the body, what instruments are available, and how organs are monitored non-invasively—even tissues hidden by skin and bone.
Key reviews discuss the ability of NIR spectroscopy to aid the diagnosis of breast cancer, bladder dysfunction, pre-term and new-born infants, psychiatric disorders, and work-related back injuries. NIR is also being used as an aid to sports medicine and as a component in brain –computer interfaces.
Optical methods using visible and near infrared (NIR) light are powerful tools for understanding human health and improving disease detection and treatment. The major tissue absorbers include haemoglobin, lipids, melanin, water and proteins. Oxygenated and de-oxygenated haemoglobin (O2Hb; HHb) preferentially absorb visible and NIR light of different wavelengths, as evidenced by the more reddish colour of oxygenated blood and the more bluish hue of deoxygenated blood. O2Hb and HHb have distinct spectra, therefore optical measurements can provide information on tissue oxygenation, oxygen consumption and blood haemodynamics.
Whilst researchers in the field of medical NIR spectroscopy need to continue to develop new instrumentation and applications, the challenge for physicians is to learn the advantages of NIR-based technologies and to use them in a wide range of medical conditions to assist patients. This collection of papers provides a sound basis to move to this next phase.
“As it is now 30 years since the initial findings, we felt that it was time to assess current and future trends in medical NIR spectroscopy”, pioneer NIR researcher and Guest Editor of this issue Dr Karl Norris said.
“The advantages that NIR presents are considerable and include low cost per sample, more rapid analysis and the ability to operate in a number of in-field or on-line/at-line environments, hence leading to savings in laboratory cost, gains in product value. It is our hope that this special issue will encourage greater interaction between medical and other users of NIR spectroscopy”, added Guest Editor Professor Marco Ferrari.