Dr. George J. Counelis is a Board-Certified neurosurgeon who specializes in complex brain and spinal problems. He received his medical training at Tufts University School of Medicine in Boston. After a post-doctoral clinical fellowship in cerebral blood flow at UCLA, he completed his internship and six years of neurosurgical training at the Hospital of the University of Pennsylvania. During his training at the University of Pennsylvania, he completed fellowships in brain tumor research and complex spinal surgery. In 2004, Dr. George J. Counelis joined the medical staff of John Muir Health and was chosen as the Medical Director of the Brain Tumor and Neuro-Oncology Program in 2008.

Dr. Chen is certified by the American Board of Neurological Surgery. He received his medical training at the Yale University School of Medicine, where he also completed his internship and residency. Dr. Chen is a neurosurgeon at John Muir Health where he specializes in minimally invasive approaches to the spine, tumors of the brain and spine, and cervical spine disease.

Dr. Merkow is a Board-Eligible neurosurgeon who specializes in minimally invasive spine surgery, brain tumors and functional neurosurgery. After finishing medical school at the Columbia University Medical Center, he completed his internship and residency at the Hospital at the University of Pennsylvania. Dr. Merkow received his fellowship training at the Wellington Public Hospital.

Dr. Cheng completed medical school at the University of California at San Francisco, where he also finished his internship and residency in neurological surgery. Dr. Cheng is a neurosurgeon who specializes in traumatic brain injury, minimally invasive spine surgery, and pituitary surgery.

Cristina received her Bachelor's Degree in Business in 1994 and her Associate's Degree in Nursing from Los Medanos College. She began her career as an Oncology Nurse in 2009 and earned her Radiation Therapy Certificate in 2012. She has been a Nurse Navigator in Radiation Oncology at John Muir Health since 2012, and is currently studying for her Oncology Certification.

Dr. Massullo is certified by the American Board of Radiology/Radiation Oncology. He completed medical school at Mayo Medical School, and his internship and residency at University of California at San Francisco. Dr. Massullo completed his research fellowship with the American Cancer Society. Prior to joining the Radiation Oncology team at John Muir Health, he was a clinical faculty member at the University of California at San Diego.

Dr. Moini is certified by the American Board of Radiology/Radiation Oncology. After completing medical school at the Universita Cattolica Del Sacro Cuore, Milan, Italy, she completed her internship at Yale University School of Medicine. Her residency program was at Johns Hopkins University School of Medicine. She has held faculty positions at Johns Hopkins University and University of California at Davis Medical Center.