Exploratory Study of Cavity Ringdown Spectroscopy as a Noninvasive Breath Diagnostic for Breast Cancer

摘要

Every woman over 50 is recommended to have mammograms to monitor for breast cancer. The goal is to detect breast cancer as early as possible. The problems with the technique are well known and range from the exposure to X- rays to the difficulty of analysis, to patient resistance. Normal human breath contains a complex mixture of volatile organic compounds (VOCs). A number of these VOCs have been identified as candidate markers of various cancers (e.g. formaldehyde in breast cancer). Although breath analysis has been shown to have great potential as a diagnostic tool, most of the compounds of interest are exhaled in picomolar concentrations. Real-time breath analysis for these compounds is not possible with existing technology. Cavity ringdown spectroscopy (CRDS) is a measurement of the rate of absorption of a sample within a closed optical cavity, rather than the standard measurement of the absorbed signal strength over a given sample path. It maintains much of the simplicity of classical absorption spectroscopy, but has been demonstrated to provide an increase in sensitivity of up to 10,000 times. The objective is to evaluate the potential of CRDS to provide real-time formaldehyde concentrations in exhaled breath for the purpose of the detection of breast cancer.