Doctor profile · Federal record
Dr. Ruth Williamson, MD
Radiation Oncology Physician (CMS: Radiation Oncology) · Pasadena, CA
- NPI 1952486912
- Accepts Medicare
- MIPS 84.1 / 100 · 2023
- 37 yrs in practice
- Female
- Group practice
- No sanctions
Practice & contact
Operates at 2 locations .
- Primary practice
-
625 S Fair Oaks Ave Ste 100
Pasadena, CA 911052640
(626) 397-5149
fax (310) 397-2147 - Additional location
-
100 W California Blvd
Pasadena, CA 911053010 - Mailing address
-
4140 W 190Th St
Torrance, CA 905045513
Credentials & registration
- NPI registered
- October 2006 — 20 yrs on file
- Profile last updated
- October 13, 2022
- Year of graduation
- 1989 — 37 yrs since
- Specialty taxonomy
- 2085R0001X — NUCC code
- State license (1)
- California #G707B5C
- Medicaid
- CA #GR0087110
Federal sanctions & exclusions
No sanctions, exclusions or revocations on file
Checked against OIG LEIE on NPI 1952486912. Last verified May 11, 2026.Medicare procedures · 2023
Top services delivered
Total services
1,308
Distinct HCPCS
10
Medicare allowed
$140,587
| HCPCS | Description | Services | Patients | Avg allowed | |
|---|---|---|---|---|---|
77334 |
Design and construction of complex radiation treatment device | 282 | 72 | $65 | |
77427 |
Radiation treatment management, 5 treatment sessions | 272 | 74 | $205 | |
77300 |
Calculation of radiation therapy dose | 200 | 70 | $35 | |
77014 |
Ct guidance for insertion of radiation therapy fields | 169 | 29 | $48 | |
99214 |
Established patient office or other outpatient visit, 30-39 minutes | 96 | 65 | $103 | |
77290 |
Obtaining data needed to develop the optimal radiation treatment, 3 or more treatment areas or any number of treatment areas where special treatment is involved | 92 | 57 | $89 | |
77263 |
Complex radiation therapy planning | 53 | 53 | $180 | |
99205 |
New patient office or other outpatient visit, 60-74 minutes | 48 | 48 | $191 | |
77295 |
3d radiation therapy planning | 47 | 47 | $242 | |
77261 |
Simple radiation therapy planning | 18 | 16 | $76 |
In context: peer comparison
Among 1 peers in Pasadena Radiation Oncology Physician, average services per provider: 109. This provider delivers 12× the peer median.Medicare Part D · 2023
Top prescriptions
Total claims
33
Patients
26
Total drug cost
$3,548
| Drug | Type | Claims | Patients | Total cost |
|---|---|---|---|---|
| Clobetasol Propionate | Generic | 33 | 26 | $3,548 |
Frequently asked questions
What is Dr. Ruth Williamson's medical specialty?
Dr. Ruth Williamson practices Radiation Oncology Physician in Pasadena, CA.
Where does Dr. Ruth Williamson practice?
Dr. Ruth Williamson practices at 625 S Fair Oaks Ave Ste 100, Pasadena, CA 911052640. Office phone: 6263975149.
What is Dr. Ruth Williamson's NPI?
Dr. Ruth Williamson's National Provider Identifier (NPI) is 1952486912, issued by NPPES.
Does Dr. Ruth Williamson accept Medicare assignment?
Yes. Dr. Ruth Williamson accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Ruth Williamson commonly perform?
Top Medicare-reported procedures in 2023: Design and construction of complex radiation treatment device (HCPCS 77334); Radiation treatment management, 5 treatment sessions (HCPCS 77427); Calculation of radiation therapy dose (HCPCS 77300). Source: CMS Medicare Physician & Other Practitioners file.