title: Pulsed diode laser-based singlet oxygen monitor for photodynamic therapy: in vivo studies of tumor-laden rats.
abstract: Photodynamic therapy (PDT) is a promising cancer treatment that involves optical excitation of photosensitizers that promote oxygen molecules to the metastable O(2)(a(1)Delta) state (singlet oxygen). This species is believed to be responsible for the destruction of cancerous cells during PDT. We describe a fiber optic-coupled, pulsed diode laser-based diagnostic for singlet oxygen. We use both temporal and spectral filtering to enhance the detection of the weak O(2)(a-->X) emission near 1.27 microm. We present data that demonstrate real-time singlet oxygen production in tumor-laden rats with chlorin e6 and 5-aminolevulinic acid-induced protoporphyrin photosensitizers. We also observe a positive correlation between post-PDT treatment regression of the tumors and the relative amount of singlet oxygen measured. These results are promising for the development of the sensor as a real-time dosimeter for PDT.
authors.affiliation: Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810-1077, USA. lee@psicorp.com
authors.forename: Seonkyung
authors.initials: S
authors.lastname: Lee
authors.forename: Danthu H
authors.initials: DH
authors.lastname: Vu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Hinds
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Davis
authors.forename: Alvin
authors.initials: A
authors.lastname: Liang
authors.forename: Tayyaba
authors.initials: T
authors.lastname: Hasan
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008297:Male; D010092:Oximetry / Q000295:instrumentation* / Q000379:methods; D010778:Photochemotherapy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000378:metabolism; D051381:Rats; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*