@article{bargo02b,
  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 = {Endoscopic Optical Measurements in Cancer Patients to Quantify Sensitizing Drug Concentration and Blood Perfusion},
  journal = {Laser Med. Surg.},
  year = {2002 abstract only},
  volume = {S14},
  pages = {49},
  abstract = {The purpose is to document the variation in photosensitizing drug uptake and blood perfusion on patients who undergo Photodynamic Therapy (PDT). Blood perfusion affects the optical penetration depth of treatment light and the depth of treatment. \vskip2mm Methods involved the development of a portable optical fiber spectroscopic system 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 Photofrin. \vskip2mm Results for the blood perfusion ranged from 0.2\% to 15\% representing an optical penetration depth variation of 1 to 6\,mm. The mean values for tumors and normal tissues were 3.2\,mm and 3.8\,mm respectively. Absorption coefficients from 0.19 to 2.2\,cm$^{-1}$ and reduced scattering coefficient from 4 to 23.7\,cm$^{-1}$ were measured at treatment wavelength (630\,nm). 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. \vskip2mm In conclusion, there was significant patient-to-patient variation in the blood perfusion and optical penetration depth, and in the drug concentration. 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.},
}