Lasers in Medicine and Biology

Chair: Steven Jacques, Oregon Medical Laser Center

Summary: Light scattering depends on a tissue's ultrastructual composition and absorption depends on a tissue's chemical composition. Together absorption and scattering determine how light transports through the tissue. This session summarizes the current understanding of these relationships.

1. Andrew K. Dunn (Univ. of California at Irvine):
   Microscopic origins of tissue scattering
2. Judith Mourant (Los Alamos National Laboratory):
   Experimental measurements of light scattering in cell suspensions: origins of scattering and differences in malignant and nonmalignant cells.
3. David Boas (Tufts University):
   Light scattering: the transition from single scattering to diffusion
4. Willem Star and Steven Jacques:
   Experimental demonstration of tissue optics: just for fun!

Chair: Rebecca Richards-Kortum, University of Texas at Austin

Summary: This session will highlight recent efforts to develop and test optical spectroscopy to identify and monitor neoplastic lesions in situ. New developments in the clinical application of reflectance, fluorescence and Raman spectroscopies will be considered. Special emphasis will be given to models to understand the morphologic and biochemical basis of spectroscopic signatures of neoplasia.

1. Phil Haydon (Iowa State University):
   Near-field microscopy applied to biological samples
2. Gerwin J. Puppels (Erasmus University Rotterdam):
   In vivo tissue characterization by Raman spectroscopy
3. Michael Feld (Massachusetts Institute of Technology):
   Diagnosing Invisible Disease With Scattered Light
4. R.M. Hoffman (AntiCancer, Inc.):
   Green fluorescent protein: a new light to study metastasis and angiogenesis

Chair: Raimund Hibst, University of Ulm

Summary: This session addresses new ideas, observations and comprehensive modeling of radiation tissue interaction mechanisms relevant to therapeutic laser applications in medicine and dentistry. It will cover theoretical or experimental work towards new concepts for therapy as well as a better understanding of actual applications.

1. Raimund Hibst (Session Chair): Introduction :
   Actual questions and new directions in laser dentistry
2. Daniel Fried (University of California, San Francisco):
   Novel methods of dental hard tissue ablation and modification
3. Scott Prahl (Oregon Medical Laser Center):
   Laser induced cavitation bubbles in medicine
4. Alfred Vogel (Medical Laser Center Luebeck):
   Basic effects and potential therapeutic applications of ultrashort laser pulses

Chair: J. Stuart Nelson, Beckman Laser Institute, University of California at Irvine

Summary: Novel video techniques for dermatology. Optical targetting of hair follicles. Biology of skin resurfacing. Surface cooling during laser treatment of selected dermatoses.

1. Steve Jacques (Oregon Medical Laser Center):
   New video techniques for dermatology
2. Rox Anderson (Massachusetts General Hospital):
   Optical targetting of hair follicles
3. Bahman Anvari (Rice University):
   Surface cooling methods in conjunction with laser treatment of selected dermatoses
4. Victor Ross (Naval Hospital, San Diego):
   Laser skin resurfacing: a critical appraisal of the role of thermal damage in modulation of wound healing and improved cosmesis

Tuesday Afternoon (4:00pm-6:00pm): Poster Session I

Chair: Eva Sevick-Muraca, Purdue University

Summary: The physics, chemical physics, engineering, and instrumentation of in vivo and in situ optical imaging and and diagnostics. Photoacoustic imaging, photon migration measurements in tissues, fluorescent contrast agents, and the development of new imaging and instrumentation approaches for in vivo optical mammography.

1. Maria Angela Franceschini (Laboratory for Fluorescence Dynamics):
   Non-invasive optical studies of the human brain, breast, and skeletal muscle
2. Alexander A. Oraevsky (University of Texas Medical Branch):
   Laser optoacoustic imaging for tissue characterization
3. Jeffrey Reynolds (Purdue University):
   Multi-pixel frequency-domain measurements of diffusing photon density waves

Chair: Christoph K. Hitzenberger, University of Vienna

Summary: This session focuses on some recent developments and new directions in optical coherence tomography (OCT): improvement of resolution and speed, obtaining information on additional structural (e.g. birefringence) and functional (blood flow velocity) parameters, and alternative schemes of OCT.

1. Christoph Hitzenberger (chair):
   Introduction to optical coherence tomography
2. Gerd Haeusler (University of Erlangen-Nuernberg):
   Spectral radar - an alternative method for optical tomography
3. Zhongping Chen and Johannes De Boer (Univ. of California at Irvine):
   Functional imaging of biological tissue with optical coherence tomography
4. Mark Brezinsky (Massachusetts General Hospital):
   High resolution endoscopic/catheter based imaging with optical coherence tomography

Chair: Daniel Farkas, Carnegie Mellon University

Summary: This session will highlight recent developments in multiphoton excitation; gene expression probes/physiological monitoring in cells; very high resolution (axial or NSOM) and single molecule imaging; lifetime, luminescence and spectral imaging; live cell/automated/in vivo imaging and optical manipulation.

1. Daniel Farkas (Chair):
   Overview and microspectral bioimaging
2. Tony Wilson (University of Oxford):
   New approaches to improving light microscopy
3. Stefan Hell (Max Planck/Goettingen):
   Multiphoton multifocal microscopy
4. Alan Verkman (Univ. of California San Francisco):
   Intracellular measurements using green fluorescent proteins

Chair: Reginald Birngruber, Medical Laser Center Lübeck

Summary: Spatial confinement of photothermal and photomechanical effects can be achieved by using single or multiple short term laser exposures. Molecular denaturation kinetics and micro-cavitation dynamics will be discussed as the primary interaction mechanisms. Microtargeting using exogenous light absorbers can be used to to generate the microeffects speciffically at biologically important intracellular sites.

1. James Lepock (Univ. of Waterloo):
   Mechanisms of thermal damage in cells and tissues
2. Daniel Jay (Harvard Univ.):
   Chromophore assisted laser micro-effects
3. Charles Lin (Massachusetts General Hospital):
   Micro-cavitation
4. G. H¸ttmann (Medical Laser Center L¸beck):
   Thermal micro-effects

Thursday Afternoon (4:00pm-6:00pm): Poster Session II

Chairs: Tayyaba Hasan, Massachusetts General Hospital, and Willem Star, University Hospital Rotterdam

Summary: Recent clinical results with new drugs (mTHPC and other). Mechanistic aspects: the role of oxygen and photobleaching; immunological effects of PDT, in particular the role of tumor associated macrophages.

1. T. Hasan and W. Star (Session chairs):
   Overview of Photodynamic Therapy
2. Paul Baas (Amsterdam):
   Clinical applications of mTHPC-mediated PDT
3. Willem Sluiter (Rotterdam):
   How Blood Neutrophils Determine Successful Photofrin-based Photodynamic Therapy
4. M. Korbelik (Vancouver):
   Anticancer activty of immune cells mediated by photodynamic therapy