Non-Invasive Deep Tissue PH Monitor.

摘要

The feasibility of pH determination in deep tissue, using non- invasive spectroscopic techniques, has been demonstrated for samples of both blood tissue phantoms and homogenized bovine muscle tissue phantoms. The tissue phantoms were designed to scatter light similarly to human tissue. Fourier transform near infrared reflectance spectra were obtained for the tissue phantom samples. The bovine samples varied in pH from 6.2 to 7.6, pH being adjusted using acid (lactic acid) or base (sodium hydroxide) additions. Commercial arterial blood gas (ABG) instrumentation was used as the pH reference. The reliability of the reference method and viability of the muscle homogenate was confirmed by nuclear magnetic resonance spectroscopy on a sample subset. Multivariate calibration of the VIS/NIR reflectance spectra against the ABG reference pH values yielded clinically relevant results. The standard error of prediction for pH was 0.049 pH units and 0.042 pH units using two spectral regions that were found to contain pH-specific information. The results demonstrate that it is feasible to make a deep tissue pH determination based on easily obtained visible/near infrared spectral data.