Broadband reflectance measurements of light penetration, blood oxygenation, hemoglobin concentration, and drug concentration in human intraperitoneal tissues before and after photodynamic therapy

University of Pennsylvania, Department of Physics and Astronomy, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396, USA.
Journal of Biomedical Optics (Impact Factor: 2.86). 01/2005; 10(1):14004. DOI: 10.1117/1.1854679
Source: PubMed


We evaluate Photofrin-mediated photodynamic therapy (PDT) in a phase 2 clinical trial as an adjuvant to surgery to treat peritoneal carcinomatosis. We extract tissue optical [reduced scattering (mu(s)'), absorption (mu(a)), and attenuation coefficients (mu(eff))] and physiological [blood oxygen saturation (%S(t)O2), total hemoglobin concentration (THC), and photosensitizer concentration (c(Photofrin))] properties in 12 patients using a diffuse reflectance instrument and algorithms based on the diffusion equation. Before PDT, in normal intraperitoneal tissues %S(t)O2 and THC ranged between 32 to 100% and 19 to 263 microM, respectively; corresponding data from tumor tissues ranged between 11 to 44% and 61 to 224 microM. Tumor %S(t)O2 is significantly lower than oxygenation of normal intraperitoneal tissues in the same patients. The mean (+/-standard error of mean) penetration depth (delta) in millimeters at 630 nm is 4.8(+/-0.6) for small bowel, 5.2 (+/-0.67) for large bowel, 3.39(+/-0.29) for peritoneum, 5.19(+/-1.4) for skin, 1.0(+/-0.1) for liver, and 3.02(+/-0.66) for tumor. c(Photofrin) in micromolars is 4.9(+/-2.3) for small bowel, 4.8(+/-2.3) for large bowel, 3.0 (+/-1.0) for peritoneum, 2.5(+/-0.9) for skin, and 7.4(+/-2.8) for tumor. In all tissues examined, mean c(Photofrin) tends to decrease after PDT, perhaps due to photobleaching. These results provide benchmark in-vivo tissue optical property data, and demonstrate the feasibility of in-situ measurements during clinical PDT treatments.

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Available from: Michael Solonenko, Oct 09, 2015
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    • "For DRS data analysis, a multi-wavelength fitting algorithm was applied to extract parameters [23–25]. The background counts were subtracted from the tissue reflectance before normalization with a diffuse reflectance standard. "
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    ABSTRACT: Photodynamic therapy (PDT) efficacy depends on the local dose deposited in the lesion as well as oxygen availability in the lesion. We report significant interlesion differences between two patients with oral lesions treated with the same drug dose and similar light dose of 2-1[hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH)-mediated photodynamic therapy (PDT). Pre-PDT and PDT-induced changes in hemodynamic parameters and HPPH photosensitizer content, quantified by diffuse optical methods, demonstrated substantial differences between the two lesions. The differences in PDT action determined by the oxidative cross-linking of signal transducer and activator of transcription 3 (STAT3), a molecular measure of accumulated local PDT photoreaction, also showed >100-fold difference between the lesions, greatly exceeding what would be expected from the slight difference in light dose. Our results suggest diffuse optical spectroscopies can provide in vivo metrics that are indicative of local PDT dose in oral lesions.
    Biomedical Optics Express 09/2012; 3(9):2142-53. DOI:10.1364/BOE.3.002142 · 3.65 Impact Factor
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    • "Photodynamic therapy (PDT) has become a common therapeutic treatment in medicine with the rapid development of laser technology in recent years [1] [2]. For safe and effective implementation of PDT in clinical applications, accurate calculation of light dose is necessary. "
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    Photochemistry and Photobiology 09/2007; 83(5):1040-8. DOI:10.1111/j.1751-1097.2007.00139.x · 2.27 Impact Factor
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