Image: The photo on the left shows the entire three-in-one spectroscopy system on an easily transportable utility cart. The right photo is a close-up of the probe (Photo courtesy of the University of Texas, Austin).
A team of biomedical engineers has designed an instrument for the rapid diagnosis of skin cancer that does not rely on examination of biopsy specimens.
Skin cancer is detected currently by examining biopsy specimens. However, statistics suggest that for every case of skin cancer detected there are roughly 25 negative biopsies performed. To correct this situation, investigators at the University of Texas, Austin (USA) combined three advanced spectroscopy instruments into a single tool for scanning skin lesions and detecting changes in the way that skin tissues interact with light when normal skin becomes cancerous with enlarged cell nuclei and disorganization of the uppermost layers of the skin.
The multimodal spectroscopy (MMS) device characterizes the tissue microenvironment via morphological changes observed through DRS (diffuse reflectance spectroscopy) and biochemical information via RS (Raman spectroscopy) and LIFS (laser-induced fluorescence spectroscopy).
The DRS measurement is a function of tissue scattering and absorption properties, which in turn are dependent upon tissue morphological changes. Therefore, analysis yields information about tissue blood fraction, oxygen saturation, tissue scattering coefficient, nuclear morphology, and collagen structure. LIFS is biochemically sensitive, as it interrogates endogenous fluorophores such as nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), and collagen. Their fluorescence levels change with cancer progression that is associated with altered cellular metabolic pathways (NADH, FAD) or an altered structural tissue matrix (collagen). Raman spectroscopy exploits the inelastic scattering (so-called “Raman” scattering) phenomena to detect spectral signatures of important disease progression biomarkers, including lipids, proteins, and amino acids.
The spectroscopic and computer equipment required by the system fits onto a portable utility cart, and the probe is about the size of a pen. Each reading takes about 4.5 seconds to perform.
"Skin is a natural organ to apply imaging and spectroscopy devices to because of its easy access," said senior author Dr. James W. Tunnell, associate professor of biomedical engineering at the University of Texas, Austin. Most devices have been at the research stage for the last 10 years or so, but several are now undergoing clinical development. This probe that is able to combine all three spectral modalities is the next critical step to translating spectroscopic technology to the clinic."
A detailed description of the MMS device was published in the August 5, 2014, online edition of the journal Review of Scientific Instruments.
University of Texas, Austin