“Biophysical
Determinants of Photodynamic Therapy
and
Approaches to Improve Outcome”
Dr. Theresa Busch
Department of Radiation
Oncology
School of Medicine,
University of Pennsylvania
Tuesday, May 12, 2009 6:30pm
Location: Photodigm Inc.
Click here for the directions to Photodigm Inc.
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Abstract
Our primary research focus is the
investigation of photodynamic therapy (PDT) for the treatment of solid
malignancies. PDT involves the local illumination of tumors that have
accumulated a photosensitizer following exogenous administration of either the
photosensitizer itself or its precursor.
The light-excited photosensitizer interacts with oxygen in the treated
tissues (tumor) to produce reactive oxygen species that damage the tissue and
its associated stroma, including the supporting vascular network. Insomuch as oxygen is a substrate in the
photochemical reactions initiated by PDT, it is both required for and consumed
by PDT. However, in addition to oxygen
consumption by the photochemical process, impairment of oxygen delivery through
PDT-created vascular damage, or the simultaneous occurrence of both of these
processes can lead to the development of response-limiting hypoxia during therapy. Our research is centered on defining the
intratumor and intertumor distributions of biophysical factors that contribute
to PDT response, such as oxygenation, blood flow, photosensitizer concentration
and light distribution. Based on our
knowledge of PDT-associated heterogeneities in these factors, we devise and
test approaches to modulate or monitor them in such a way as to improve
therapeutic outcomes.
Biography
Dr. Theresa
Busch received her Ph.D. in Biophysics in the Roswell Park Cancer Institute
Graduate Division, University of Buffalo, State University of NY (SUNY). She completed a postdoctoral fellowship at
the University of Pennsylvania, and she is presently a Research Assistant
Professor in the Department of Radiation Oncology, School of Medicine,
University of Pennsylvania. Dr. Busch
has performed extensive research on the biological effects of photodynamic
therapy (PDT) on normal and malignant tissues.
Her particular research interests include the effects of PDT on tumor
hypoxia and blood flow, as well as mechanisms of controlling PDT-created oxygen
depletion toward the goal of improving treatment outcome. These interests
extend to the clinic, where she has performed studies on photosensitizer uptake
and the presence of hypoxia in the tumor and normal tissues of patients to
receive PDT. She has a long-standing
publication record in these areas, including a number of invited works in the
form of reviews, editorials or book chapters.
Among her publications, she has had manuscripts chosen as a Featured Article in Clinical Cancer Research and represented on the cover of Cancer Research. In addition to leading an active
translational research program in PDT, Dr. Busch served as the Director of the
Radiation Oncology Research Seminar Series from 2001-2006. As the director of
this series she invited and oversaw the visits of locally, nationally, and
internationally renowned guest lecturers in radiation biology or related
fields. Currently, she is the coordinator of Cancer Biology, a lecture series for medical residents in radiation
oncology. She has mentored many students, ranging from undergraduate to medical
level, in PDT-related research projects.
She also has served as a member of a special NIH study section assembled
to review SBIR/STTR proposals (2002-2003), as well as an ad hoc member of
Radiation Study Section. Dr. Busch’s
laboratory is supported primarily through several NIH grants, including RO1
grant, PDT Effects on Tumor Oxygenation
and Blood Flow (PI Busch); Program Project Grant, Photodynamic Therapy for Neoplastic Diseases Involving Serosal Surfaces
(PI Glatstein, Project 3 Leader Busch) and an imminent RO1 grant, Oxygen and photosensitizer levels in
photodynamic therapy of head and neck tumors (PI Busch).