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Proceedings Paper

In vivo validation of high frequency ultrasound-guided fluorescence tomography system to improve delivery of photodynamic therapy
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Paper Abstract

Photodynamic therapy (PDT) for skin cancer is sometimes only partially effective, due to inadequate levels of the fluorescent drug (photosensitizer, PS) and due to heterogeneous distribution of PS within the tissue. To image the PS distribution within skin tumors, we have developed a fluorescence tomography system (FTS) that combines a fluorescence detection array with a high frequency ultrasound (HFUS) transducer. In this paper we describe in vitro and in vivo validation of this new system. The target fluorophore for detection was Protoporphyrin IX (PPIX). Validation experiments were performed in vivo using a subcutaneous tumor model in which A431 tumor-bearing mice were treated with 5-aminolevulinic acid to induce production of PPIX. FTS reconstructions were compared with standard histology and with data from bulk tumor slices imaged ex vivo on a fluorescence scanner. Reconstructed images obtained from the FTS were correlated with the histology and the ex vivo scans, confirming several-fold increases in PPIX fluorescence in the skin and in the tumor relative to the surrounding tissues. Our data demonstrate the feasibility of using the FTS for subsurface imaging of PPIX in skin carcinoma in vivo. Future aims are to use this device for individualized treatment planning, in order to improve overall patient responses to PDT.

Paper Details

Date Published: 10 February 2011
PDF: 8 pages
Proc. SPIE 7886, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XX, 788610 (10 February 2011);
Show Author Affiliations
Akshat Paliwal, The Cleveland Clinic (United States)
Sason Torosean, Dartmouth College (United States)
Josiah Gruber, Dartmouth College (United States)
Julia O'Hara, Dartmouth College (United States)
Tayyaba Hasan, Wellman Ctr. for Photomedicine, Massachusetts General Hospital (United States)
Brian Pogue, Dartmouth College (United States)
Edward V. Maytin, The Cleveland Clinic (United States)

Published in SPIE Proceedings Vol. 7886:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XX
David H. Kessel; Tayyaba Hasan, Editor(s)

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