Current Residents

Barbara Garcia, MS

Chief Medical Physics Resident

My family emigrated from a small rural town in Michoacán, Mexico to the suburbs of Westchester County, NY, where I was born and raised. I earned my BA in physics and mathematics at Manhattanville College after an AA in social science at a community college. In this time, I completed a SULI internship at Princeton Plasma Physics Laboratory (PPPL) working on nanoparticle-based hydrodynamic turbulence experiments adjacent to an ongoing magnetorotational instability experiment. My longing to help others using physics eventually led me to Hofstra University for an MS in medical physics. I spent this time in the clinic as a medical physics assistant and conducted research on a direct dosimetric comparison of GammaKnife and VMAT SRS plans for Arteriovenous Malformations. When I am not in the clinic, I love to bake, do word searches, explore Philly’s restaurant scene, and travel the world with my best friends.

Lin Ma, PhD

Chief Education Officer

I grew up in an industrial city one-hour drive south of Beijing (both are well known for stand-up comedy). I obtained a bachelor's degree in physics at Peking University, after which I moved across the Pacific to Dallas and joined the newly-opened graduate program at UTSW. Five years were spent there, concluded by a PhD degree in medical physics and a dissertation about AI applications in treatment planning. When I am off work, you can find my wife and me on the hiking trails and tennis courts in the suburb.

Stewart Mein, PhD

I was born in Princeton, NJ, and grew up near New Hope in Bucks County. I earned my BS degree in bioengineering and electrical engineering from the University of Pennsylvania, MS in medical physics from Duke University, and Ph.D. in physics from Heidelberg University. Over the last ten years, I studied and worked abroad in various parts of Germany, e.g., Karlsruhe, Magdeburg, Dresden, and Heidelberg. Most recently, my post-doctoral work occurred at the German Cancer Research Center (DKFZ), University Clinic Heidelberg, and Heidelberg Ion-beam Therapy Center (HIT). My clinical and research interests involve computational and experimental methods in particle therapy using light and heavy ions. Outside the clinic, I enjoy swimming, playing board games, and hanging with my Jack Russell named Rascal.​ 

Julia Pakela, PhD

I was born in northern Indiana and moved to Ann Arbor Michigan when I was 11.  I completed my undergraduate studies at the University of Michigan, earning a bachelor’s degree in Physics with minors in Biochemistry and Language, Literature, and Culture of Ancient Rome. I continued my education at UM earning a PhD in Applied Physics, where I investigated the use of stochastic optimization and deep learning algorithms incorporating elements of quantum theory for radiotherapy treatment planning and prediction of patient anatomical changes for adaptive planning. My research interests broadly include the use of computing (including optimization, machine learning, and deep machine learning) to advance radiotherapy treatment as well as the ethical challenges of incorporating artificial intelligence into the radiotherapy workflow. In my free time I enjoy cooking and learning about the history and origins of different cuisines, attending live jazz and classical concerts with my husband, and binging true crime documentaries.

Khayrullo Shoniyozov, PhD

I was born and raised in Surkhandarya, Uzbekistan. After receiving a BSc degree in physics at the National University of Uzbekistan, I continued my graduate studies abroad, first in Trieste, Italy, doing a diploma course in High Energy Particle Physics at the ICTP, then got my MSc in Theoretical Nuclear Physics and PhD in Experimental Nuclear Physics from Ohio University and the University of Kentucky respectively. During my graduate studies at UKY, I performed low energy proton and neutron scattering experiments in the Van de Graff Accelerator Laboratory, and developed GEANT/Monte Carlo simulations for layered Gamma-Neutron Scintillation Detector Design and participated in its production and testing. I worked with multi-institutional COMPTON@MAX-Lab collaborators in MAX-lab Accelerator Laboratory located in Lund, Sweden, performing Elastic Compton Scattering experiments for my PhD dissertation. In 2016, after earning my PhD from UKY, I joined the Radiation Oncology Department at the University of Pennsylvania as a Proton SARRP Radiation Research Facility Manager and assumed Technical Director responsibilities for the Cell and Animal Radiation Core in 2019. Throughout my time at Penn, I have coordinated and helped facilitate radiobiology experiments for ultra-high dose rate proton (FLASH) and photon radiation therapy experiments. In my free time, I enjoy hiking, playing chess and spending time with my family and friends.

Daniel Alexander, PhD

I grew up in southern Rhode Island and moved to Troy, NY to attend Rensselaer Polytechnic Institute (RPI) where I received a BS and MS, both in physics. While there, my research focused on experimental particle astrophysics, specifically detector technology for dark matter search experiments. I then moved back to New England to complete my PhD in medical physics at Dartmouth, where my dissertation focused on novel applications of Cherenkov emission imaging in radiation therapy as part of a collaboration between the Thayer School of Engineering and the Dartmouth-Hitchcock Medical Center. During the latter half of my PhD studies, I also had the opportunity to work as a research scientist with DoseOptics LLC, where I worked on the development and commercial deployment of the BeamSite clinical Cherenkov imaging system. My current research interests include optical imaging, in vivo surface dosimetry, and image guided radiation therapy. In my free time, I enjoy playing music, hiking and skiing the northeast, cooking, and playing with my polydactyl cat, Hallux.

Jace Grandinetti, PhD

I grew up in a small suburb outside of Dallas, TX and attended the University of Texas at Arlington where I earned my BS degree in Physics. Here, I gained an early exposure to research in a high-energy physics lab and also interned at Fermi Lab where I characterized the performance of a novel Cherenkov detector for use at CERN. I then received my MS in Medical Physics at Vanderbilt University before eventually continuing to UT Southwestern and earning a PhD in Medical Physics where my research was focused in ultra-low-field MRI. While there, I constructed a novel MRI system for preclinical MR-guided radiation experiments and also developed deep learning models to improve the reconstruction quality of low-field MR images. Outside the clinic, I enjoy playing guitar, traveling with my wife, and spending time with my two cats.

Elvia Odalis Reyes Guevara, MS

I was born and raised in Guatemala. I received my BS in physics at Universidad del Valle de Guatemala. I decided to move to the United States to pursue a master’s degree in medical physics at the University of Pennsylvania, where my thesis research focused on the commissioning of a 7-degree-of-freedom robotic arm for preclinical proton FLASH pencil-beam scanning. In my spare time, I enjoy exploring the coffee shop scene at Philly, watching movies with my friends, and tease them about learning Spanish with me.

Ahmad Sakaamini, PhD

I was born and raised in Southern California. My academic journey started at California State University Fullerton, where I earned my BS and MS in Physics. The next stop was England, where I earned my PhD in Physics from the University of Manchester (UK), with a dissertation on electron impact ionization experiments on methane and nitrogen via (e,2e) coincidence techniques to test quantum mechanics’ models. I engaged in two distinct postdoc experiences. My first was back at CSU Fullerton, focusing on experiments which included the measurements of benchmark angle-differential cross-section ratios for the electron-impact excitation of both xenon and krypton. My second postdoc brought me to the University of Pennsylvania where I developed a robotic system for use in brain SRS and other radiation treatment modalities. The work involved high-speed electronics, low-level hardware programming, image-guided system integration, gel dosimetry fabrication, and treatment planning for SRS. One of my key interests lies in FLASH radiotherapy, development of robotics, and AI-driven solutions for optimizing radiotherapy treatment planning routines. Beyond my professional pursuits, I harbor a deep love for black & white photography, traveling, and music.

Melissa Vila, MS

I was born in Voorhees, New Jersey to parents who emigrated to the United States from Lima, Peru. For the better part of my life, I lived in the northern region of Delaware. I completed my undergraduate studies at the University of Delaware in 2019, where I received a BS in physics and minored in mathematics. Two years later I began my graduate studies and received an MS in medical physics from the University of Pennsylvania in 2023. During this time, I worked on a novel approach for the development of a three-dimensional dosimeter with applications in FLASH proton radiotherapy. In my free time I enjoy playing tennis, going to the movies, trying new restaurants and ice cream places in Philly, and spending time with my friends and family.

Brook Byrd, PhD

My family is from Williamsburg, Virginia, an 18th century colonial town located in southern Virginia.  I completed my BS in Applied Physics with a minor in Ethical Leadership studies at Christopher Newport University in 2017. During my time at CNU, I played collegiate tennis, led multiple community service trips, and performed nuclear detector research at the nearby Thomas Jefferson National Accelerator facility, a national lab also located in Newport News, Virginia. With a strong passion for bridging science with service, I pursued a UK-US Fulbright Fellowship in Radiotherapy, and explored virtual radiotherapy training opportunities (VERT), 3D visualization solutions for CBCT/CT image matching, and methods for improving Radiotherapy education within the UK. This highly cross-cultural Fulbright exchange also provided me with a wider global perspective, humility, and empathy; which continues to shape my actions today. Penn’s shared interest in cross-cultural communications and global collaboration is another leading factor for why I choose to be a part of this program.

After moving back to the US, I pursued a PhD in engineering at the Thayer School of Engineering at Dartmouth College with a certificate in Medical Physics and Surgical Innovation. My doctoral research at Dartmouth spanned multiple fields and I’ve been lucky to work with surgeons, radiologists, pathologists, oncologists, technicians, research scientists, and many mentors along the way. Over the 5 years of my PhD career, I was involved in over a dozen preclinical imaging collaborations and four major clinical studies. My research also supported a start-up breast cancer surgical guidance company, CairnSurgical Inc., in multiple clinical trials which aimed to make supine MRI an efficient and cost-effective imaging strategy for breast cancer surgical guidance. 

Through these clinical experiences, I discovered a deep passion for patient care and a strong motivation to improve lives through clinical work. With interest in the intersections of clinical practice, scientific advancements, and commercial translation, I’m excited to remain involved in all three spheres during my time here as a 3-yr research resident. When I’m not in the clinic, I’m an avid swimmer, runner, and world-traveler.