Daniel Chikvashvili, MD
Cardiology
Dr. Jessica Berrios, MD
Chairman, Emergency Medicine
Peter A. Guiney, DO, FACOFP
Family Medicine
Dr. Peter Guiney serves as director of the Family Medicine Residency Program and chairman of the newly created Department of Family Medicine at Nassau University Medical Center. He earned his medical degree at the New York College of Osteopathic Medicine (now New York Institute of Technology College of Osteopathic Medicine), and is a graduate of the University of Notre Dame.
Dr. Guiney completed his Family Medicine Residency at Peninsula Hospital Center. After completion of his residency training, he worked as an attending physician in the Peninsula Hospital Emergency Room for several years. He became director of the Family Practice Residency Program and director of Medical Education at Peninsula Hospital Center in the years following. He practiced privately in Ozone Park, Queens, for more than 20 years, and has served as medical director at Daytop Village Inc., a multinational drug rehab facility in Queens.
Dr. Guiney has practiced in the underserved community throughout his entire professional life. He remains committed to the training of family medicine doctors to address the current national physician shortage, and recruiting program graduates for ongoing primary care service in the NuHealth/LIFQHC Family Health Centers.
Paul Mustacchia, MD, FACP, MBA
Medicine
Paul Mustacchia graduated from SUNY Buffalo School of Medicine. He completed his residency and fellowship training at Columbia Presbyterian Medical Center in New York, New York. He is a board-certified Internist and Gastroenterologist. For the past 9 years, he has served as Chief Physician and Gastroenterology Fellowship Program Director at Nassau University Medical Center. He is also a member of the Internal Medicine Residency Leadership Committee Medical and Professional Affairs Committee, and Quality and Professional Affairs Committee at Nassau University Medical Center. For the past 5 years, he has served as Associate Chairman of Medicine, and for the past 3 years he has also served as President of the Medical Staff.
Paul Pipia, MD
PM&R
Dennis Murphy, MD
Orthopedics
Susan Wu, MD
Pathology & Laboratory
Dr. Susan Wu is board certified in Anatomic and Clinical Pathology with subspecialty certification in Cytopathology by the American Board of Pathology. Dr. Wu serves as the Chair of the Department of Pathology and Laboratory Medicine at NuHealth / Nassau University Medical Center (NHCC /NUMC) since 2024. She brings more than 21 years of experience in pathology practice and over 15 years of leadership experience as a departmental chair at Mount Sinai South Nassau prior to joining NHCC /NUMC.
Dr. Wu received her Doctor of Medicine and Master of Medicine degrees from Harbin Medical University in China. She completed her residency training in Anatomic and Clinical Pathology at Eastern Virginia Medical School in Virginia in 2000. Following residency, she pursued advanced fellowship training in Surgical/Oncologic Pathology at Memorial Sloan-Kettering Cancer Center and completed an additional fellowship in Cytopathology.
In addition to leading the Department of Pathology and Laboratory Medicine, Dr. Wu oversees Blood Bank and Transfusion Medicine services and serves as chair of the Hospital Transfusion Committee and Tissue Committee. She is committed to advancing quality patient care, laboratory and Pathology service excellence, and interdisciplinary collaboration within the organization. Dr. Wu is also passionate about medical education and enjoys teaching residents and providing educational presentations to residents, faculty members, and nursing staff.
Sehar Ejaz, MD
Pediatrics
Constantine Ioannou, MD
Psychiatry
Dr. Ioannou earned his M.D. degree from St. Georges University School of Medicine. He completed an Internship in Internal Medicine at The Methodist Hospital in Brooklyn, and then completed his Residency in Psychiatry at SUNY-Downstate. He stayed on at Kings County Hospital beginning with a position in the HIV Program, where he was in charge of the Psycho-social services and as a faculty member of the AIDS Education and Training Center. He assumed a series of responsibilities at Kings County Hospital within a variety of Public Psychiatry services before moving to Long Island, where he held the position of Medical Director of Substance Abuse Services at Glen Cove Hospital. He eventually came to NUMC, where he was Vice Chairman of Clinical Services for the Department of Psychiatry until moving to Stony Brook University Hospital as Director of Residency Training for General Psychiatry.
In addition to his work in Public Sector psychiatry and work with the SPMI population, he has maintained his interest in psychodynamic psychotherapy and is a member of the CJ Jung Institute and has completed training in Meaning Centered Psychotherapy. He teaches both Nassau University Medical Center and Stony Brook psychiatric residents. He also supervises psychiatric residents in providing insight oriented psychotherapy and supportive expressive psychotherapy. He is a Clinical Assistant Professor of Psychiatry at Stony Brook University and has presented at a variety of conferences with a focus on Ethics, Historical Context of the Mental Health System and the History of Opiate Use in the United States.
Steven Lev, MD
Radiology
Dr. Steven Lev is originally from Brooklyn and graduated from Princeton University, earning an A.B. with cum laude honors in chemistry. He completed his medical school training at the Mount Sinai School of Medicine in 1988; followed by an internship year in Internal Medicine at Lennox Hill Hospital. He went on to complete a Residency in Diagnostic Radiology at Beth Israel Medical Center in New York, and a Fellowship in Neuroradiology at New England Medical Center Tufts University School of Medicine in Boston.
Dr. Lev joined Nassau University Medical Center (NUMC) in 1995 as Director of Neuroradiology. He was promoted to Radiology Chairman in 2020, having previously served as Acting Vice-Chair and Acting-Chair for the department. Dr. Lev holds an appointment as Associate Professor of Clinical Radiology at the Renaissance School of Medicine at Stony Brook.
Dr. Lev serves on several NUMC committees, including Radiation Safety and Informatics. He was a member-at-large on the NUMC Medical Staff from 2011 to 2012. He is also on the executive committee of the Long Island Radiological Society (LIRS), where he functioned as its President in 2018. He co-leads the quality program for the NUMC Radiology Department and has implemented vital safety and patient care initiatives, such as those concerning stroke care and trauma, which have been adopted by the institution.
Dr. Lev is committed to student and Resident training and education and serves as both Director of the Academic Affairs Committee and Radiology Medical Student Course Director. He has an extensive range of research interests; presenting over 120 exhibits and oral presentations and receiving numerous accolades. He is the published author of multiple peer-reviewed articles and electronic publications and he has been a Journal Reviewer for both the American Journal of Radiology (AJNR) and the British Journal of Radiology (BJR).
He is also an artist and a photographer. He enjoys weightlifting, physical fitness and endurance sports.