The Technology Behind the DDx
The key to the very high level of diagnostic accuracy of Multi-Modal Spectroscopy and the DDx is in analytically looking at the suspect lesion from three different scientific perspectives. These perspectives come from three spectroscopic methods: Diffuse Reflection Spectroscopy, Laser Induced Fluorescence Spectroscopy, and Raman Spectroscopy. Each of these methods measures different biologically significant parameters; each one contributes unique and complementary information, thereby greatly increasing diagnostic accuracy.
- Reflectance spectroscopy (known as Diffuse Reflectance Spectroscopy or “DRS”) uses diffusely scattered white light to determine tissue scattering and absorption. The spectrum of the reflected light provides information on the tissue’s micro-architecture, hemoglobin and melanin content, and oxygen saturation. Since these qualities vary with skin condition, they will be different in diseased tissue than in healthy skin, providing key diagnostic information.
- Fluorescence spectroscopy (known as Laser Induced Fluorescence Spectroscopy or “LIFS”) uses ultraviolet light to excite characteristic fluorescence from tissue. LIFS is sensitive to endogenous fluorophores such as the metabolic coenzymes nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), providing insight into cellular metabolism. In addition, LIFS measures the status of structural proteins such as collagen and elastin, key indicators of a tumor’s morphology and invasiveness. These are also important signs of diseased tissue.
- Raman spectroscopy provides detailed information on chemical composition by probing tissue using near infrared light. A small fraction of the infrared photons that scatter from the tissue excite molecular vibrations in the molecules. The resulting scattered photons (“Raman” photons) have energy lower than the energy of the incident photons. The spectrometer system is designed to measure the energy spectrum of these photons. This spectrum reflects the molecular vibrational energy levels and allows chemical identification down to specific molecules. Chemical changes thus detected, including changes in the amounts of specific biochemical species, invasion by new species, or depletion of normal levels in healthy tissue, are powerful indicators of disease.
Each of these techniques provides diagnostic information complimentary to the others. Combining this diverse information is what makes the DDx so powerful. Fully utilizing information on morphology, metabolism, and chemical composition from the three different spectroscopic measurements gives results much more accurate than from any single method alone, and far more accurate than visual examination.
To produce reliably excellent diagnostic results, the diverse information must be combined using sophisticated digital data analysis methods. New algorithms for processing information from the MMS methods are incorporated in the DDx.
MMS is a powerful method for diagnostic analysis of living tissue. It combines three analytical measurement methods: Raman, reflectance, and fluorescence spectroscopies. These optical analyses are done directly on patients’ skin, quickly, painlessly, and non-invasively. With introduction of the DDx this method has become the most accurate in-clinic diagnostic technology available for skin cancer diagnosis. It is effective for all major types of skin cancer. Trials indicate that in-clinic diagnostic accuracy of MMS is at or above 95% for Melanoma and Basal Cell Carcinoma, and 87% for Squamous Cell Carcinoma. These are the three most common and dangerous skin cancers.
The DDx brings Multi-Modal Spectroscopy (MMS) to skin cancer diagnosis. This technology looks at the biology and biochemistry of the lesion, thereby seeing indications of cancer that the trained eye cannot see. In the clinic, this tool is an invaluable aid to doctors in diagnosing skin cancer.
CLINICALLY DEMONSTRATED ACCURACY OF THE DDx
Results of a clinical study demonstrate the accuracy of the DDx methodology (MMS). Results are compared to those obtained by the study dermatologists using traditional visual methods.