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Monitoring Tumor Response During Photodynamic Therapy Using Near‐infrared Photon‐migration Spectroscopy ¶
Author(s) -
Pham Tuan H.,
Hornung René,
Berns Michael W.,
Tadir Yona,
Tromberg Bruce J.
Publication year - 2001
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2001)0730669mtrdpt2.0.co2
Subject(s) - photodynamic therapy , spectroscopy , photon , infrared , two photon excitation microscopy , near infrared spectroscopy , optics , materials science , chemistry , physics , fluorescence , organic chemistry , quantum mechanics
Benzoporphyrin‐derivative (BPD)–monoacid‐ring A photodynamic therapy (PDT) was performed on subcutaneous tumor implants in a rat ovarian cancer model. In order to assess PDT efficacy the tumor and normal tissue optical properties were measured noninvasively prior to and during PDT using frequency‐domain photon migration (FDPM). FDPM data were used to quantify tissue absorption and reduced scattering properties (given by the parameters μ a and μ′ s , respectively) at four near‐infrared (NIR) wavelengths (674, 811, 849 and 956 nm). Tissue physiologic properties, including the in vivo concentration of BPD, deoxy‐hemoglobin (Hb), oxy‐hemoglobin (HbO 2 ), total hemoglobin (TotHb), water (H 2 O) and percent tissue hemoglobin oxygen saturation (%S t O 2 ), were calculated from optical property data. PDT efficacy was also determined from morphometric analysis of tumor necrosis in histologic specimens. All the measured tumor properties changed significantly during PDT. [Hb] increased by 9%, while [HbO 2 ], [TotHb] and %S t O 2 decreased by 18, 7 and 12%, respectively. Using histologic data we show that long‐term PDT efficacy is highly correlated to mean BPD concentration in tumor and PDT‐induced acute changes in [HbO 2 ], [TotHb] and %S t O 2 (correlation coefficients of 0.829, 0.817 and 0.953, respectively). Overall, our results indicate that NIR FDPM spectroscopy is able to quantify noninvasively and dynamically the PDT‐induced physiological effects in vivo that are highly correlated with therapeutic efficacy.