@article{bargo02a,
  author = {Paulo R. Bargo and Teresa Goodell and Rodger Sleven and George Koval and Greg Blair and Scott A. Prahl and Steven L. Jacques},
  title = {Spectroscopic Measurements to Quantify Sensitizing Drug Concentration and Blood Perfusion},
  journal = {Proceedings of the Oregon Academy of Science},
  volume = {38},
  pages = {44},
  year = {2002 abstract only},
  abstract = {We documented the variation in photosensitizing drug uptake and blood perfusion on patients who undergo endoscopic Photodynamic Therapy (PDT) for treatment of esophageal and bronchial cancer. Blood perfusion affects the optical penetration depth of treatment light and the depth of treatment. A portable optical fiber spectroscopic system was developed for endoscopic procedures that uses reflectance to specify the tissue optical properties (light penetration depth) and uses reflectance-corrected fluorescence to determine drug accumulation. Tissue simulating phantoms were used to calibrate the system. Measurements on seven patients were taken prior to PDT irradiation, 2 days after injection of Photofrinª. Measured blood perfusion ranged from 0.2\% to 15\% representing an optical penetration depth variation of 1 to 6\,mm. The mean depth for tumors and normal tissues was 3.2 and 3.8\,mm respectively. The measured absorption and reduced scattering varied from 0.19 to 2.2\,cm$^{-1}$ and from 4 to 23.7\,cm$^{-1}$ respectively (at the treatment wavelength of 630\,nm). The measured photosensitizing drug concentration measurements ranged from 0.5 to 20\,mg/ml. In vitro results showed an error of $+$10\% in the determination of the drug concentration in the phantom samples. Significant patient-to-patient variation in the blood perfusion and optical penetration depth, and in the drug concentration was observed. Optical measurements can document the PDT dose received by a patient, rather than the administered dose (mg/kg body weight of drug and J/linear cm of light), which do not account for the patient-to-patient variation.},
}