Radiation Physics Research

The long-term goal of the Radiation Physics Research Program in the Department of Radiation Oncology at the University of Pennsylvania is to develop innovative therapeutic solutions for the treatment of human disease. Advancements made towards this goal involves applied physics research in many areas that include high energy proton and photon radiation, use of artificial intelligence (AI) methods, FLASH radiation therapy, photodynamic therapy, dosimetry techniques, and innovative image guided approaches to target radiotherapy for improving patient outcome. Our program is unique in the breadth and depth of the research available and in the wealth of collaborative activities both nationally and internationally as well with industry.

Current support for our research and educational goals include:

  • 3 Program Project grants (P01) with our Radiation Biology Division in Translational Studies in FLASH Particle Radiotherapy, Pleura Photodynamic Therapy and Radiation and Checkpoint Blockade for Cancer Immune Therapy.
  • Several R01 grant funded research on topics such as: Photodynamic Therapy, Proton Beam Planning, Photo-Acoustics, Ultrasound Hyperthermia, Robotic and Frameless SRS.
  • Partnership with Industry supported research: various research grants IBA and VARIAN on new technology and treatment modalities, such as Flash radiotherapy and biologically guided online adapted SBRT.
  • Individual faculty research activities many of the funded by the Department of radiation Oncology and by the University.
  • National Institute of Health (NIH) and National Cancer Institute (NCI) funded research.
  • A large number of collaborative funded research activities with other institutions.
  • Global Education and Global Health initiatives funded by the NCI, American Institute of Physics (AIP) and others.

Radiation Physics Division Links


Stephen Avery, PhD

Associate Professor

Dr. Avery has expertise in Protoacoustics, the measurement of sound waves generated by clinical proton beams, with a specific application of combining kHz ultrasound signals to proton therapy. He is working to develop end-to-end testing of a 3D dosimetry system for ultra-fast dose rate (FLASH) proton treatments and model the effects of 3D motion during treatment.

Lei Dong, PhD


Dr. Dong has significant contributions to IMRT optimization, deformable image registration, adaptive radiotherapy, and proton therapy.

Alireza Kassaee, PhD

Associate Professor

Dr. Kassaee has research interests on the application of 3D printing for customization of QA phantoms in proton radiotherapy, polymer gel dosimetry in proton therapy and proton Flash therapy, and application of novel dosimetry detectors such as laser vibrometer and piezo film for proton range verification in protoacoustics.

Michele Kim, PhD

Assistant Professor

Dr. Kim has research interests in Proton FLASH radiation dosimetry and instrumentation, small animal radiobiological studies, and photodynamic therapy dosimetry.

Rafe Mcbeth, PhD

Assistant Professor

Dr. McBeth has expertise in computational methods for radiation therapy including artificial intelligence, Monte Carlo simulation, and automation techniques. His clinical research interests include the ethical and safe integration of artificial intelligence and automation into clinical practice.

Dimitris Mihailidis, PhD

Associate Professor

Dr. Mihailidis has made significant contributions in electron beam dosimetry, managing of radiotherapy patients with cardiac implanted devices and other devices and, in clinical development of new technologies in the clinic. In addition, his investigations include, dosimetry and calibration protocols for Flash beams, use of detectors for electron dosimetry and Flash beam dosimetry and verification and quality control and dose management of dental Cone Beam CT systems.

Shannon O’ Reilly, PhD

Assistant Professor

Dr. O’Reilly has research interests in functional lung imaging, Monte Carlo dosimetry, and reducing radiation-induced toxicities. She specializes in proton therapy and investigates the use of dual energy CT as well as aspects related to thoracic radiotherapy.

Kevin Teo, PhD

Associate Professor

Dr. Teo has research focused on the applications of advanced imaging tools to improve quantification and reduce proton range uncertainties. These include implementing the use of dual energy CT (DECT) for proton planning and treatment with reduced range uncertainty margins as well as perfusion blood volume imaging for functional lung imaging studies.

Rodney Wiersma, PhD

Associate Professor

Dr. Wiersma research is focused on investigation of ultrahigh dose rate FLASH for radiation therapy, development of quality assurance (QA) systems, image guidance radiation therapy (IGRT) systems, treatment planning optimization, and the application of robotics to radiation therapy (RT).

Ying Xiao, PhD


Dr. Xiao performs research on knowledge-based planning quality research for both Intensity Modulated Radiotherapy (IMRT) and Intensity Modulated Proton Therapy (IMPT), deep learning based quantitative quality assurance of structure delineation, and predictive modeling for outcome driven clinical guidelines, standardization for AI implementation, and voxel level dosimetry for radio-pharmaceutical therapy.

Timothy Zhu, PhD


Dr. Zhu has significant contribution to explicit Photodynamic Therapy (PDT) dosimetry, PDT reactive oxygen species explicit dosimetry (ROSED), integrated system for interstitial and intracavitory PDT, diffuse optical tomography, diode in vivo dosimetry, and external beam radiation transport.