Dr. Stack is board certified in diagnostic radiology. He received his bachelor's degree from Yale University, his medical degree from Rutgers University and his MBA degree from Columbia University. Dr. Stack first came to Westchester County in 1988 for his radiology residency at New York Medical College. He earned the position of chief resident, and has continued to practice in Westchester County since that time.

Since 1995, Dr. Stack has been a member of the Society of Breast Imaging, specializing in mammography, 3-D mammography, breast ultrasound, breast MRI and imaging-guided breast procedures. Dr. Stack is past president of the New York Breast Imaging Society, and is author of the book "The Breast Health Checklist: Simple Checklists to Keep you Organized, Informed, and in Control." He is also author of the chapter "Stereotactic Breast Biopsy" in the medical textbook, Kuerer's Breast Surgical Oncology, and he was awarded a research grant for his work in digital mammography. Dr. Stack holds the rank of Clinical Assistant Professor at New York Medical College. He has presented numerous papers at scientific meetings, is published in medical journals, and has lectured nationally.

In 2016, Dr. Stack was awarded the Dr. Leonard Finkelstein Excellence Award. This award was presented by the Summit Health (formerly Westmed Medical Group) Board of Directors to recognize one physician each year. The award was presented to one physician, nominated by physician colleagues and employees, who demonstrated the highest level of clinical quality along with compassion and selfless devotion to patient care. Dr. Stack was recognized in Westchester Magazine as a "Top Doctor" in 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023 and 2024.