Therapeutic Radiologists in California
Data updated monthly · Last refresh October 2026
28 Therapeutic Radiology providers practice in California, including 3 (11%) offering telehealth. The largest concentration is in San Francisco. Profiles include federal Open Payments records of money received from drug and device companies in 2025. Listings are drawn from federal public records and are not endorsements.
28providers
3telehealth
San Franciscotop city
Therapeutic Radiology by city in California
Choose a city to see providers there.
Where Therapeutic Radiologists in California practice
From CMS Medicare enrollment records covering 8 of the 28 providers listed here (29%). Providers who do not bill Medicare are not included in these figures.
Largest practice groups
| Group (as registered with Medicare) | Therapeutic Radiologists | All clinicians in group | Main city |
| Sutter Bay Medical Foundation | 2 | 3,783 | San Luis Obispo |
Sources: CMS Doctors and Clinicians (August 2026) and Facility Affiliation files (August 2026); hospital ownership type and overall star rating from CMS Hospital General Information (July 2026). A clinician in several groups is counted once, in the largest group they bill through. Ownership type is what the hospital reports to CMS; it does not show private equity or other investor ownership. How we build this directory.
Therapeutic Radiology providers in California
Listed by city, largest first. Payment figures come from the federal Open Payments program, which requires drug and device companies to report what they pay physicians for consulting, speaking, meals, travel and royalties. A disclosed payment is a financial relationship, not evidence of wrongdoing, and many totals reflect a single meal. Figures cover calendar year 2025.
Dr. Patrick Welton, MDCarmel, CA · No drug or device payments recorded (2025) ·
(831) 620-6633 Dr. Dave Yamauchi, MDDuarte, CA · No drug or device payments recorded (2025) ·
(626) 359-8111 Dr. Dwight Stickney, M.D.Granite Bay, CA · No drug or device payments recorded (2025) ·
(916) 600-5116 Dr. Thavinsakdi Viravathana, M.D.Hemet, CA · No drug or device payments recorded (2025) ·
(951) 537-6002 Dr. Reinhard Schulte, M.D.La Jolla, CA · No drug or device payments recorded (2025) ·
(858) 452-5020 Dr. Joseph Hodgkins, (RT)(R)(MR)(ARRT)Long Beach, CA · No drug or device payments recorded (2025) ·
(562) 826-8000 Dr. Joan Ryoo, MD, MSHSLos Angeles, CA · $218 in drug and device payments (2025) · Telehealth ·
(323) 783-2841 Dr. Michael Senikowich, M.D.Los Angeles, CA · No drug or device payments recorded (2025) ·
(323) 865-3050 Dr. Nilam S Ramsinghani, MDOrange, CA · No drug or device payments recorded (2025) ·
(714) 456-8978 Dr. Don Goffinet, M.D.Palo Alto, CA · No drug or device payments recorded (2025) ·
(650) 723-5714 Dr. Gordon Ray, MDPalo Alto, CA · No drug or device payments recorded (2025) ·
(650) 853-2954 Dr. Owen Kim, M.D.Porterville, CA · No drug or device payments recorded (2025) ·
(559) 788-6175 Dr. John Clark, M.D.Redding, CA · $183 in drug and device payments (2025) ·
(530) 246-4971 Dr. Steve Benak, M.D.Riverbank, CA · No drug or device payments recorded (2025) ·
(209) 869-4850 Dr. Narayana Memula, M.D.San Bernardino, CA · No drug or device payments recorded (2025) ·
(909) 887-8800 Dr. Bryan Leigh, M.D.San Clemente, CA · No drug or device payments recorded (2025) ·
(949) 248-4547 Dr. Jay Tassin, M.D.San Clemente, CA · No drug or device payments recorded (2025) ·
(949) 248-4547 Dr. Mack Roach, M.D.San Francisco, CA · $8,086 in drug and device payments (2025) ·
(415) 353-7175 Dr. Richard Krieg, MDSan Francisco, CA · No drug or device payments recorded (2025) ·
(415) 353-7175 Dr. Robert Johnson, M.D.San Luis Obispo, CA · No drug or device payments recorded (2025) · Telehealth ·
(805) 541-1932 Dr. Harvey Frey, M.D.Santa Monica, CA · No drug or device payments recorded (2025) ·
(310) 394-6342 Dr. Ralph Hanahan, M.D.Santa Rosa, CA · No drug or device payments recorded (2025) ·
(707) 522-6875 Dr. Ronald Van Roy, M.D.Santa Rosa, CA · No drug or device payments recorded (2025) ·
(707) 525-1150 Dr. Henry Wong, M.D.Stockton, CA · No drug or device payments recorded (2025) ·
(209) 467-6335 Dr. Pauling Chang, MDSunnyvale, CA · No drug or device payments recorded (2025) · Telehealth ·
(408) 730-2820 Dr. Bryan Chang, MDTorrance, CA · $1,196 in drug and device payments (2025) ·
(310) 517-4750 Dr. Florian Ploch, MDVacaville, CA · No drug or device payments recorded (2025) ·
(707) 624-8100 Common questions
How many Therapeutic Radiology providers are in California?There are 28 Therapeutic Radiology providers with active NPI records practicing in California, according to federal NPPES data refreshed monthly.
Do Therapeutic Radiology providers in California offer telehealth?Yes. 3 of the 28 Therapeutic Radiology providers in California (about 11%) report offering telehealth services in CMS data.
Which cities in California have the most Therapeutic Radiology providers?San Francisco (2), Palo Alto (2), Santa Rosa (2) have the highest concentration of Therapeutic Radiology providers in California.
How many Therapeutic Radiology providers in California received drug or device company payments?5 of 28 Therapeutic Radiology providers in California (18%) received at least one payment from a drug or device company in 2025, according to the federal Open Payments program.
Where does this data come from?Provider counts and profiles come from the federal NPPES registry and CMS Doctors and Clinicians files. Payment figures come from the CMS Open Payments program for calendar year 2025. The directory refreshes monthly.
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