Marc T. Fields, MD
Radiation Oncology Physician · Rohnert Park, CA
Marc T. Fields, MD is a radiation oncology physician with a practice address in Rohnert Park, California, and NPI 1730143066, issued on Apr 13, 2006. Check the license (California C52087, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Marc T. Fields
- Credential
- MD
- Primary taxonomy
- Radiation Oncology Physician 2085R0001X
- License number
- C52087 CA
Self-reported in NPPES; status is on the state search - Practice location
- 301 Professional Center Dr, Rohnert Park, CA 94928
- Phone
- (209) 543-0684
- Enumerated
- Apr 13, 2006
- Record last updated
- Jul 19, 2023
- Fax
- (209) 343-3809
- Medicaid ID
- 00C520870 CA
- Medicare enrollment
- Enrolled (PECOS I20060120000247); accepts Medicare assignment
- Medical or professional school
- University Of Missouri, Kansas City, School Of Medicine, 1994
- Entity
- Type 1 · individual
8 nearest radiation oncology physician records → All 735 in California → Look up another NPI →
Also registered at 301 Professional Center Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Peter Hawkins, M.D., PH.D.Radiation Oncology Physician1962820621
- Irwin Lee, MDRadiation Oncology Physician1861510760
- Nikhil Rao, MDRadiation Oncology Physician1275737850
Verify Marc T. Fields in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license C52087Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
19% more Medicare Part D claims than the average radiation oncology physician in 2024
160 Medicare Part D claims for 57 beneficiaries, against an average of 134 among the 4,851 providers of this specialty who prescribed in Part D. 21 claims were for opioids.
Most prescribed
- Lidocaine Hcl Viscous36 claims
- Chlorhexidine Gluconate16 claims
- Hydrocodone-Acetaminophen14 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Cancer Therapy Medical Group IncRohnert Park, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Marc T. Fields among 735 radiation oncology physician records in California
Marc T. Fields, MD is one of 735 radiation oncology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 16% of them.
- NPI issued2006 · 16% of these records are older, 55% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 74% of these records are
- Graduated1994 · median 2005 among the 545 with a school on file
- Record last updated2023 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 2085R0001X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Radiation Oncology Physician providers in California
There are 735 radiation oncology physician records in California.
All 735 in California → Every provider in Rohnert Park → Radiation Oncology Physician nationwide →
The 8 radiation oncology physician records with the nearest ZIP codes
- Peter Hawkins, M.D., PH.D.Rohnert Park, CA 949281962820621
- Irwin Lee, MDRohnert Park, CA 949281861510760
- Nikhil Rao, MDRohnert Park, CA 949281275737850
- Allan Rappaport, M.D., J.D.Tiburon, CA 949201346310539
- Mark Rounsaville, MDNicasio, CA 949461033100284
- Francine Halberg, MDGreenbrae, CA 949041275515256
- Lloyd Miyawaki, MDGreenbrae, CA 949041497737464
- Joseph Poen, MDGreenbrae, CA 949041972585941
Common questions
What is Marc T. Fields, MD's NPI number?
Marc T. Fields, MD's National Provider Identifier (NPI) is 1730143066, issued on Apr 13, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Marc T. Fields, MD located?
The NPPES record lists a practice address at 301 Professional Center Dr, Rohnert Park, CA, 94928. Phone: (209) 543-0684. Providers update this record themselves, so call before visiting.
How can I verify Marc T. Fields, MD's license?
NPPES lists California license number C52087, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Marc T. Fields, MD prescribe under Medicare Part D?
In 2024, Marc T. Fields, MD had 160 Medicare Part D claims for 57 beneficiaries; the average among radiation oncology physician prescribers was 134. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.