Lauren DiMarino, DO
Program Director
Dr. Lauren DiMarino earned her Doctor of Osteopathic Medicine degree from Lake Erie College of Osteopathic Medicine and completed her internal medicine residency at Geisinger Medical Center, where she subsequently served as Chief Resident. She joined the faculty in hospital medicine in 2009, became Associate Program Director in 2010, and has served as Program Director of the Internal Medicine Residency since 2016. She also serves as Co-Program Director of Geisinger’s Internal Medicine/Nephrology Pathway, an AIRE pilot program.
Dr. DiMarino is board certified in internal medicine and holds recertification in Focused Practice in Hospital Medicine. She is an Associate Professor of Medicine at Geisinger College of Health Sciences and a Clinical Adjunct Associate Professor at Philadelphia College of Osteopathic Medicine. She is a Fellow of both the American College of Osteopathic Internists and the American College of Physicians (ACP), and she is a Distinguished Member of the Geisinger Academy of Educators. In 2026, she received the Pennsylvania ACP Dr. Ann Preston Women in Medicine Award.
Her national work centers on residency recruitment, learner assessment, individualized learning plans, and the transition from medical school to residency. She has served in leadership roles with the Alliance for Academic Internal Medicine (AAIM) and the Association of Program Directors in Internal Medicine (APDIM), including an elected term on the APDIM Council. She currently serves as AAIM’s lead representative to the Association of American Medical Colleges National Collaborative to Improve the Transition to Residency and has contributed to national recommendations and peer-reviewed scholarship supporting learners across the undergraduate-to-graduate medical education continuum. Mentorship remains central to her work with residents, medical students, and faculty, particularly in helping learners navigate transitions, develop individualized goals, and grow as physicians and educators.
Dan Dometita, DO
Associate Program Director
Director, Osteopathic Recognition
Director, Residency Clinic
Dr. Dometita received his medical degree from the Edward Via College of Osteopathic Medicine (VCOM) in 2012. He completed his Internal Medicine residency at Geisinger Medical Center in 2015 and remained at Geisinger as Chief Resident from 2015–2016. He subsequently joined the residency’s leadership team as Director of Osteopathic Recognition and was appointed Associate Program Director in 2018.
Dr. Dometita practices both Hospital Medicine and General Internal Medicine and serves as the Resident Clinic Director. He is actively involved in resident education, curriculum development, recruitment, and program innovation, with particular interests in ambulatory medical education, osteopathic education, and the safe integration of artificial intelligence into graduate medical education and clinical practice. He is also the faculty advisor for both the Recruitment Council and the Social Media Council.
Nationally, he is a member of the program planning committee of the Association of Program Directors in Internal Medicine (APDIM), and he is a Fellow of the American College of Physicians. He also holds academic appointments with Geisinger Commonwealth School of Medicine and the Philadelphia College of Osteopathic Medicine. He is a graduate of Geisinger’s Medical Education Certificate Course and a Distinguished Member of the Geisinger Academy of Educators.
Outside of medicine, Dr. Dometita enjoys traveling and exploring the outdoors with his wife, Crystal, and their three children, Braeden, Arabella, and Eris. He is also an avid Philadelphia Eagles fan. Go Birds!
Jamie Hood, DO
Associate Program Director
Director, Chief Residency Program
Dr. Jamie Hood earned her Doctor of Medicine degree from the Philadelphia College of Osteopathic Medicine and completed her Internal Medicine residency training at Geisinger Medical Center. After serving as Chief Resident during the 2019-2020 academic year, she joined the residency program leadership team and was appointed Associate Program Director in 2021.
As an Associate in Hospital Medicine and Medical Director of a medical-surgical unit, Dr. Hood enjoys combining her clinical work with her passion for teaching and mentorship. A Geisinger residency graduate herself, she is dedicated to creating a supportive learning environment where residents can grow both professionally and personally. She serves as Director of the Chief Residency Program, where she enjoys mentoring current and future Chief Residents and developing innovative educational initiatives, including the residency's board review curriculum. She also chairs the Program Evaluation Committee and the Hospitalist Teaching Faculty Committee.
Dr. Hood is a Fellow of the American College of Physicians, a graduate of Geisinger's Medical Education Certificate Course, and a member of the Geisinger Academy of Educators. She holds academic appointments as Clinical Assistant Professor of Medicine at both Geisinger Commonwealth School of Medicine and the Philadelphia College of Osteopathic Medicine.
Outside of medicine, Dr. Hood enjoys discovering new wines as an aspiring amateur sommelier, getting lost in a good book, and spending time with her husband, Brett, their two young children, and their cats, Doug and Fiona.
Jonathan Swinden, MD
Associate Program Director​
Director, Simulation
Dr. Swinden is an Associate in Hospital Medicine with a passion for teaching. His interests include clinical reasoning and reducing diagnostic error through greater awareness of cognitive bias and reflective practice. He is motivated by the belief that improving how clinicians think can contribute to safer, high-quality patient care.
He earned his Doctor of Medicine degree from St. George's University and completed his Internal Medicine residency at Geisinger Medical Center, where he subsequently served as Chief Resident. He has been recognized with awards for teaching, compassion, and professionalism.
He directs the residency's clinical simulation curriculum, serves as core faculty for the Geisinger Healthcare & Interprofessional Communications Program. He is a Fellow of the American College of Physicians and holds academic appointments as Clinical Assistant Professor of Medicine for Geisinger Commonwealth School of Medicine and Philadelphia College of Osteopathic Medicine. He is an alumnus of Geisinger's Medical Education Certificate Course in curriculum design and a member of the Geisinger Academy of Educators.
Outside of medicine, Dr. Swinden is an avid cyclist, an enthusiastic student of pizza making, and enjoys spending time outdoors with his wife and two daughters.
Lisa Schroeder, MD
Assistant Program Director​
​Dr. Schroeder received her Doctor of Medicine degree at the University of Wisconsin School of Medicine and Public Health at Madison in 2007. She completed her residency and chief residency in Internal Medicine and fellowship in Rheumatology at Geisinger. She serves as an Associate Professor of Rheumatology at Geisinger Commonwealth School of Medicine, as well as an Assistant Program Director for the Internal Medicine Residency program.
Dr. Schroeder develops and delivers clinical reasoning curricula and coaching programs for performance improvement in clinical reasoning and studying and test-taking skills for the Internal Medicine residency program. She also serves as core faculty for Geisinger’s Healthcare and Interprofessional Communication and Faculty Development programs.
Her educational interests include mentoring and coaching residents, fellows and medical students, specifically around clinical reasoning and communication skills as well as faculty development. She completed Geisinger’s Medical Education Certificate Course, Health Systems Science Leadership Course and is a distinguished member of the Geisinger Academy of Educators.
She enjoys reading, exercising, cooking and spending time with her husband and their two daughters.
Stefanie Leader, DO
Director, Quality Improvement and Wellness
Dr. Leader received her Doctor of Osteopathic Medicine degree at the Philadelphia College of Osteopathic Medicine in 2015. She completed her Internal Medicine Residency training at Geisinger Medical Center. She was then selected as Chief Resident for the 2018-2019 academic year.
She is currently an Associate in Hospital Medicine spending most of her clinical time teaching residents while on their inpatient Internal Medicine rotation. She serves as the Director for Quality Improvement for the Internal Medicine residency and is a member of the EQUIPS (Educators for Quality Improvement and Patient Safety) Steering Committee for the Geisinger system. She also serves as the Director of Wellness for the residency and represents the Internal Medicine Residency as the acting Well-Being Champion for the Geisinger Graduate Medical Education Well-Being Committee.
In addition, she holds academic positions as Clinical Assistant Professor for Geisinger Commonwealth School of Medicine and Philadelphia College of Osteopathic Medicine. She is an alumni of Geisinger’s Medical Education Certificate Course, ILEEd (Improving the Learning Environment for Educators) course and is a member of the Geisinger Academy of Educators.
Outside of the hospital, she enjoys road-tripping throughout the North-East with her two daughters Amelia and Avery, international travel, a variety of fitness activities, and amateur home improvement projects.
Conor Mulcahy, DO
Assistant Program Director
Dr. Mulcahy is an internal medicine physician. He cares for adults with a range of chronic and acute conditions. “I enjoy being a ‘Jack of all trades’ but have a particular interest in optimizing lifestyle to help patients live healthier lives,” he says.
Dr. Mulcahy earned his medical degree from Lake Erie College of Osteopathic Medicine in Erie. After medical school, he completed a residency at Geisinger Medical Center, where he was resident of the year.
“I love the longitudinal relationships I get to have with patients,” he notes. “I also have a passion for teaching.”
In his spare time, Dr. Mulcahy enjoys ultimate Frisbee and hiking.
Denise Keyser
Program Manager
Ms. Keyser graduated from Bloomsburg High School and Allentown Business School with an Associate
in Specialized Business degree. She started at Geisinger in 1989 as a float secretary. In 1994, she became the program administrator for the Internal Medicine Residency Program. Ms. Keyser is the
“rock” of the program, making sure each trainee successfully completes the training requirements during their three years with the program. She tells everyone that this is her “second family.”
Suzanne Noll, MEd
Program Administrator
Suzanne graduated from Bloomsburg University with a Bachelor of Arts in Communication Studies and Organizational Communication in 2017. She went on to complete her Master of Educational Leadership and College Student Affairs in 2019 also from Bloomsburg University. In 2019, Suzanne worked at Penn State Mont Alto within the Residence Life program. Suzanne entered the Geisinger system in September 2021 working in the Staffing Office then transitioning to Same Day Surgery. In October 2022, Suzanne became a Program Administrator for the Internal Medicine/Clinical Informatics. Suzanne enjoys cooking, baking, reading (loves a good murder mystery), and spending time with her family and cats.
Alex Caplan, DO
Chief Resident
As a Harrisburg, Pennsylvania native, I’ve proudly called central Pennsylvania home for most of my life. When it came time for college, I stayed close to home, attending West Chester University, where I also competed as a member of the men’s soccer team. After spending two years in clinical research, I traveled to the mountains of West Virginia to pursue my medical education at the West Virginia School of Osteopathic Medicine.
It wasn’t until completing a rotation at Geisinger that I truly found where I belonged. From the very first day, it was clear that the residents were not only happy and supported, but a true family. When I began residency, that same sense of community immediately made me feel at home. Combined with the unwavering support from leadership in helping me achieve my career goals, my residency experience has been incredibly meaningful.
I am honored to continue my journey as Chief Resident, with the opportunity to teach and mentor incoming learners while fostering the same culture, sense of support, and family that drew me to this program years ago.
Mustafa Shah, MD
Chief Resident
Born and raised in Peshawar, Pakistan, I came to Geisinger seeking excellent clinical training and opportunities for growth. What I found was far more than that—a community that welcomed me as if this had always been my home. From the very beginning, I was surrounded by people who were genuinely invested in my success. The faculty, staff, and residents foster an environment that is supportive, collaborative, and dedicated to helping each individual reach their full potential. At Geisinger, opportunities to learn, lead, innovate, and excel are not only available—they are actively encouraged.
Throughout my residency, I came to appreciate the unique culture that defines this program. The commitment to excellence, the strong sense of teamwork, and the unwavering support for resident development made a lasting impression on me. It became clear that I wanted to continue being part of an institution that values its people and invests so heavily in their growth. That desire led me to remain at Geisinger as a Chief Resident and, ultimately, to continue my career here as a Hospitalist.
As Chief Resident, I am excited to contribute to the culture that has given me so much. I look forward to teaching, mentoring, and guiding the next generation of physicians while helping them navigate their own professional journeys. I am particularly grateful for the opportunity to innovate, develop new educational initiatives, and contribute to the continued growth of such an exceptional program. Most importantly, I hope to provide the same encouragement, support, and sense of belonging that I received, ensuring that every trainee feels empowered to succeed and thrive within the Geisinger family.