March 14 Mar 14
11:00 AM - 12:00 PM
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Medical Physics Seminar - Eric S Diffenderfer

Physics and radiobiology experiments with proton FLASH

12:00pm – 1:00pm Seminar & Discussion

Zoom Webinar

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Eric S Diffenderfer, PhD, Assistant Professor of Radiation Oncology at the Hospital of the University of Pennsylvania

Dr. Eric Diffenderfer earned a BS in Physics from The Evergreen State College, and an MS in Physics and PhD in Nuclear Physics from Florida State University. His research interests center on preclinical studies with ultra-high dose rate proton beams, proton SARRP development, and machine learning applications in radiation oncology. His clinical responsibilities include proton and X-ray therapy physics and dosimetry. He is board certified by the American Board of Radiology.

Physics and radiobiology experiments with proton FLASH

Ionizing radiation delivered at ultra-high dose rates (UHDR) has been associated with reduced normal tissue toxicity in small animal models when compared with radiation delivered at conventional dose rates. The effect on tumor control is found to be independent of dose rate when comparing UHDR with conventional dose rates in irradiated animal tumor models. This differential normal tissue response and iso-effective tumor response has been dubbed the FLASH effect. FLASH radiation could have a potentially profound effect on cancer treatment if the technology to deliver UHDR radiation can be translated and optimized for clinical use. To this end, we have developed and validated an instrument to deliver UHDR proton beams for preclinical research in small animal models using a research proton beam line on a clinical proton radiotherapy system. We have developed several subsystems to investigate and optimize clinically relevant delivery parameters in small animal models. Among these, a dose monitoring and beam control feedback system was developed to precisely deliver proton dose at UHDR and conventional dose rate. A scattering and beam collimation system was developed to create a symmetric and uniform field with high proton use efficiency for delivering relatively large fields to small animals at all dose rates. A ridge filter was designed, and 3D printed to efficiently modulate proton beam energy and create a spread-out bragg peak. Additionally, an animal scanning system synchronized with beam delivery was developed to investigate spatially and temporally varying dose delivery on the FLASH effect.

A video of the presentation will be provided after the event.