SUMMARY High intensity pulsed-laser light can be used to excite absorbing molecules to transient states in large proportions. The laser-induced spectral changes can be characterized by

transient changes in light propagation; through the tissue provided the excited states of these molecules have altered absorption spectra. Characterization of these transient changes may

then be used to exploit new mechanisms in photosensitization and/or to optimize photobiological effects. In this study, transmittance and reflectance were measured as a function of laser

pulse energy, from tissue-simulating media as well as in rat muscle and liver slices, both with and without the photosensitizer benzoporphyrin derivative monoacid (BPD-MA) present. There was

no statistically significant difference in the depth of necrosis at 48 h after irradiation. These results indicate that photosensitizer population-state changes are measurable in tissues and

may provide a method for measuring triplet-state properties of photosensitizer in vivo, but for BPD-MA at clinically used concentrations these changes do not significantly affect the depth

of photodynamically-induced tissue damage. SIMILAR CONTENT BEING VIEWED BY OTHERS LOCAL MONITORING OF PHOTOSENSITIZER TRANSIENT STATES PROVIDES FEEDBACK FOR ENHANCED EFFICIENCY AND TARGETING

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Google Scholar  Download references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Dermatology, Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Boston,

02114, MA, USA B W Pogue, T Momma & T Hasan * Department of Pathology, Massachusetts General Hospital, Boston, 02114, MA, USA H C Wu Authors * B W Pogue View author publications You can

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Nature SharedIt content-sharing initiative KEYWORDS * photosensitizer * BPD-MA * pulsed-laser * optical dosimetry * tumour