Our commitment to patient care extends beyond delivery of quality diagnostic imaging services. We seek to provide efficient, compassionate, and courteous patient care. To meet this objective, our diagnostic facility is conveniently located, appointment scheduling is easy, and test results are reported in a timely manner. We do our very best to make sure that your appointment begins on time and that your experience with us is as comfortable as possible.

Tri-City PETCT at Vista prides itself in providing the best professional staff in San Diego County.

  Donald J. Ponec, MD

Dr. Ponec’s specialization is in Interventional Radiology, with a Certificate of Added Qualification in Vascular and Interventional Radiology. He is co-founder and Director of the San Diego Cardiac and Vascular Institute and Director of Interventional Radiology at Tri-City Medical Center.

Dr. Ponec earned his BS degree at University of Southern California and graduated magna cum laude, Phi Beta Kappa. He first moved to San Diego to complete his MD at University of California San Diego in 1979. Dr. Ponec maintains an appointment as Assistant Clinical Professor of Radiology there. His interest in research was encouraged when he received an American Heart Association grant for the study of cardiac and vascular disease at UCSD. He attended University of California San Francisco for Radiology Residency and Interventional Radiology Fellowship. His active participation in research as the Principle or Co-investigator on multiple FDA-sponsored clinical trials has produced several publications. Also, he is the National Medical Expert for a major peripheral vascular study and a Distinguished Reviewer for the "Journal of Vascular and Interventional Radiology".

  Bruce J. Biederman, MD

Tri-City PETCT at Vista is pleased to introduce Dr. Bruce Biederman. He is a Diagnostic Radiologist specializing in Coronary CTA. He has additional experience in PET/CT, Neuroradiology, Body Imaging, Musculoskeletal MR Imaging and digital Mammography.

Dr. Biederman was born in Toronto. He graduated cum laude at the University of Pennsylvania and then earned his medical degree at George Washington University School of Medicine, Washington DC. He completed an internship in Internal Medicine at Washington Hospital Center in Washington, DC, and a Diagnostic Radiology Residency at Tulane University Medical Center in New Orleans, LA, followed by an appointment as a Clinical Instructor in the Department of Radiology at Tulane.

Dr. Biederman is a Diplomate of the American Board of Radiology. He served on the Board of Directors of Emergency Cardiac Imaging, LLC, and is a member of the Society of Cardiovascular Computed Tomography. He has been in private practice in New Orleans and New Jersey, and recently relocated to Southern California with his wife and two children. He enjoys playing guitar and hockey.

  Kathleen M. Flores, MD

Dr. Flores is an expert in Magnetic Resonance Imaging of the entire body with a special interest in Musculoskeletal Imaging, Breast MRI and Brain MR Spectroscopy. She has additional skills in Nuclear Medicine, Positron Emission Tomography (PET) and Women’s Imaging. Currently, Dr. Flores is Director of MRI and Teleradiology for the group.

Dr. Flores earned her BS at University of California Irvine and her MD from University of Maryland School of Medicine. She was awarded Alpha Omega Alpha (AOA) status as a junior. She first came to San Diego in 1994 for her Clinical Transitional Internship at Mercy Hospital and Medical Center. Dr. Flores completed her Diagnostic Radiology Residency training at the University of California San Francisco. She followed this with a comprehensive MRI Fellowship at Long Beach Memorial Medical Center - MRI Center.

  Gregory K. Nicpon, MD

Dr. Nicpon's specialization is in Body Imaging, Musculoskeletal Imaging and non-invasive angiography with expertise in CT imaging.

Dr. Nicpon received his BS at University of Minnesota, graduating Magna Cum Laude. He attended New York Medical College for his MD and was elected junior Alpha Omega Alpha. Dr. Nicpon completed his Diagnostic Radiology Residency and Body Imaging Fellowship at Stanford University Medical Center.


  Stephen P. Schmitter, MD

Dr. Schmitter's specialization is in Positron Emission Tomography and Nuclear Medicine.

Dr. Schmitter received his BS degree from the University of Michigan. He was Phi Beta Kappa and graduated with highest distinction. He earned his MD at Stanford University and came to San Diego in 1995 for the Transitional Internship Program at Mercy Hospital. He completed the Radiology Residency Training Program and Nuclear Medicine Fellowship at Mallinckrodt Institute.


  David G. Evans, MD

Dr. Evans specializations are Nuclear Medicine and Positron Emission Tomography.

He received his BA with honors from the University of Texas at Austin in 1967. He earned his MD degree from the University of Texas Southwestern Medical School at Dallas in 1971. After completing his Internship and Internal Medicine Residency at Providence Hospital and Medical Center in Portland, Oregon he practiced General Practice and Emergency Medicine in Portland, then Honolulu for several years.

Dr. Evans came to San Diego in 1984 for his Nuclear Medicine Residency and Fellowship at University of California San Diego. He has served as President and Vice President for the San Diego County Nuclear Medical Society. Dr. Evans remained active with the University of California San Diego as a member on the Board of Directors for the San Diego School of Nuclear Medical Technology, and as a Volunteer Clinical Professor of Nuclear Medicine. He is currently a faculty member of the Santa Barbara School of Nuclear Medicine Technology. He has several research protocols and publications to his credit.