Michael Collard, MD

Radiology

Dr. Collard specializes in pediatric interventional radiology at Johns Hopkins All Children’s Hospital. He joined the medical staff in 2021. Dr. Collard earned his medical degree from the University of Missouri Kansas City School of Medicine in Kansas City, Missouri. He completed an internship in internal medicine at the University of Missouri Kansas City School of Medicine and a residency in diagnostic radiology at the University of Texas Southwestern Medical Center in Dallas. He then completed a fellowship in vascular and interventional radiology at Massachusetts General Hospital/Harvard Medical School in Boston, followed by a fellowship in pediatric radiology with an emphasis in interventional radiology at Boston Children’s Hospital/Harvard Medical School.

Jane Cook, DO

Radiology

Dr. Cook specializes in pediatric radiology with a focus on PET/CT and musculoskeletal imaging at Johns Hopkins All Children’s Hospital. She joined the hospital staff in 2019.

Kimberly Fagen, MD

Radiology

Dr. Fagen specializes in pediatric radiology at Johns Hopkins All Children’s. She joined the hospital staff in 2019. Dr. Fagen earned her medical degree from the Uniformed Services University of the Health Sciences in Bethesda, Maryland. She completed her internship at National Capital Consortium and residency in diagnostic radiology at Naval Medical Center San Diego. She completed a fellowship in pediatric radiology at Children’s National Medical Center.

Christopher Keup, MD

Radiology

Dr. Keup specializes in pediatric radiology at Johns Hopkins All Children’s Hospital. He joined the hospital staff in 2019. Dr. Keup also serves in the U.S. Army Reserve. He is currently attached to the Army Medical Department Personnel Management Command in Forest Park, Georgia, and is a Lieutenant Colonel in the Medical Corps. Dr. Keup earned his medical degree from the University of Missouri in Columbia, Missouri. He completed an internship in internal medicine from the University of Missouri-Kansas City in Kansas City, Missouri, followed by a residency in diagnostic radiology from the University of Missouri-Kansas City and a fellowship in pediatric radiology from Children’s Mercy Hospital in Kansas City, Missouri.

Neil Lester, MD

Radiology

Dr. Lester specializes in pediatric radiology at Johns Hopkins All Children’s Hospital in St. Petersburg, Florida. He joined the medical staff in 2023 with over a decade of attending experience. After earning his medical degree from Yale University School of Medicine, he completed his radiology residency and served as chief resident at Staten Island University Hospital. He specialized with a fellowship in pediatric radiology at Boston Children's Hospital. Dr. Lester has spent most of his career at Mount Sinai Hospital in New York City, serving as an assistant professor in the Radiology and Pediatrics departments of the Icahn School of Medicine.

Joy Masseaux, MD, MPH

Radiology

Dr. Masseaux is a pediatric radiologist at Johns Hopkins All Children’s Hospital. She sees patients at the hospital’s main campus in St. Petersburg, Florida. She joined the hospital staff in 2023. She was previously an assistant clinical professor of radiology and pediatrics at Mount Sinai Medical Center in New York.

Sally Mitchell, MD

Radiology

Dr. Mitchell is an interventional radiologist at Johns Hopkins All Children’s. She joined the hospital staff in 2021. She was most recently director of pediatric interventional radiology and director of vascular anomalies interventional radiology at Johns Hopkins University School of Medicine in Baltimore.

William Schaaf, MD

Radiology

Dr. Schaaf is a graduate of the Drexel University College of Medicine (formerly Medical College of Pennsylvania Hahnemann School of Medicine). He completed his residency in diagnostic radiology at Eastern Virginia Medical School, Norfolk, VA, where he served as chief resident. He also completed his pediatric radiology fellowship at Cincinnati Children’s Hospital Medical Center. Dr. Schaaf is board-certified in radiology and board-admissible in pediatric radiology.

Erica Schallert, MD

Radiology

Dr. Schallert specializes in pediatric radiology at Johns Hopkins All Children’s Hospital. She joined the medical staff in 2022 and sees patients on our main campus in St. Petersburg, Florida. Dr. Schallert earned her medical degree from the University of Florida College of Medicine in Gainesville, Florida. She completed an internship at John Peter Smith Hospital in Fort Worth, Texas. She then completed a residency in diagnostic radiology from the University of Miami, Miller School of Medicine, Jackson Memorial Hospital in Miami, followed by a pediatric radiology fellowship at Baylor College of Medicine, Texas Children’s Hospital in Houston.

Javier Quintana, MD

Radiology

Dr. Quintana is a radiologist at Johns Hopkins All Children’s Hospital. He joined hospital staff in 2010. Dr. Quintana earned his medical degree at the University of South Florida. He trained in general pediatrics at Jackson Memorial Hospital/University of Miami and completed a diagnostic radiology residency at Geisinger Medical Center in Danville, Pennsylvania. Dr. Quintana completed a pediatric radiology fellowship at Children’s Hospital of Philadelphia. He is fluent in Spanish.

Susan Buffington MSN, APRN, CPNP

Paul Herlan MPAS, PA-C

Natalie Mercado MPAS, PA-C

Michelle Walker MSN, APRN, CPNP