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Edit this profileWhere to find Ruth Williamson, MD
- Pasadena location main office
625 S Fair Oaks Ave Ste 100, Pasadena, CA 91105 - Pasadena location
100 W California Blvd, Pasadena, CA 91105
About Dr. Williamson
Ruth Williamson, MD is a healthcare provider in Pasadena, CA specializing in radiation oncology. Ruth trained at University of Southern California Keck School of Medicine, graduating in 1989. According to Medicare claims data, Ruth cared for 546 Medicare patients across 1,515 services. The services billed most often include ct guidance for insertion of radiation therapy fields, design and construction of complex radiation treatment device, and radiation treatment management, 5 treatment sessions. This provider record is associated with NPI 1952486912.
Factual summary compiled by Guide.md from public records; not written by this provider.
Education & Training
Specialty
Credentials & Licensing
Medicare information
Exactly as CMS reports it (National Downloadable File, Opt-Out Affidavits, Order & Referring). Not an insurance directory; confirm coverage with the office.
Contact Information
- (626) 397-5149
- Email not available
Practice Locations
625 S FAIR OAKS AVE STE 100
Pasadena, CA 91105
100 W California Blvd
Pasadena, CA 91105
Conditions Commonly Evaluated or Treated
Within Radiation Oncology generally. Availability varies by clinician, training and location — this profile has not been claimed, so nothing here is a personal claim by the provider.
Conditions
Cancer care
Most searched conditions
- Brain tumors
- Breast cancer
- Prostate cancer
Benign condition
Blood and lymph cancer
Bone cancer
- Primary Bone Cancer
Brain tumors
Cancer emergencies
- Blocked Chest Vein
- Spinal Cord Compression From Tumor
Chest cancer
Endocrine cancer
Eye cancer
Eye conditions
Foot conditions
Gastrointestinal cancer
- Anal cancer
- Bile duct cancer
- Colon cancer
- Esophageal cancer
- Gallbladder cancer
- Liver cancer
- Pancreatic cancer
- Stomach cancer
Gynecologic cancer
- Cervical cancer
- Endometrial cancer
- Ovarian cancer
- Vaginal Cancer
- Vulvar cancer
Head & neck cancer
- Nose and Sinus Cancer
- Parotid gland tumor
Head and neck cancer
- Head and neck cancer
- Laryngeal cancer
- Oral cavity cancer
Metastatic cancer
- Cancer spread to bones
- Cancer spread to spine
- Severe back pain
Neurologic condition
Orthopedic conditions
- Abnormal Bone Growth After Surgery
Sarcoma
Skin cancer
Thoracic cancer
Urologic cancer
- Bladder cancer
- Kidney cancer
- Penile Cancer
- Testicular cancer
Vascular conditions
Procedures & services
Most searched procedures
- Brachytherapy
- CyberKnife
- Gamma Knife
- Proton therapy
- Radiation therapy
Advanced radiation
- MRI-Guided Radiation Therapy
Benign treatment
- Keloid scar radiation
Brain radiation
- Whole Brain Radiation
Cancer treatment
- Post-Surgery Radiation Therapy
- Pre-Surgery Radiation Therapy
Central nervous system
- Brain and Spinal Cord Radiation
Consultation
- Cancer radiation second opinion
- Radiation oncology consultation
External radiation
- Electron beam therapy
- Image-guided radiation (IGRT)
- IMRT (Targeted intensity radiation)
- RapidArc / VMAT radiation
- Total body irradiation (TBI)
Eye cancer treatment
- Eye Plaque Radiation Therapy
Follow-up care
- Radiation skin care and follow-up visit
Heart treatments
- Heart Arrhythmia Radiation Therapy
Internal radiation
- High-Dose Rate (HDR) Radiation Implants
Pain and symptom relief
- Palliative radiation for bone pain
Particle therapy
- Heavy Ion Radiation Therapy
Precision radiation
- Adaptive radiation therapy
- Heart-sparing breath hold radiation (DIBH)
- Spine radiosurgery
- Stereotactic body radiation (SBRT)
- Stereotactic radiosurgery (SRS)
- Tattoo-free radiation
Prostate cancer treatment
- Prostate Radioactive Seed Implants
Prostate protection
- SpaceOAR Hydrogel Injection
Radiation therapy
- Radiation Boost
Skin cancer treatment
- Superficial Radiation Therapy (SRT)
Skin lymphoma treatment
- Total Skin Electron Radiation
Specialized radiation
- Heat therapy for cancer (Hyperthermia)
- Intraoperative radiation (IORT)
Targeted isotopes
- Pluvicto infusion
- Radioactive Iodine Treatment
- Xofigo injection
- Y-90 radioembolization
Targeted radiation drugs
- Lutathera Infusion
Treatment planning
- 4D CT Motion Scan
- Breathing-synchronized radiation (Respiratory gating)
- CT simulation scan
- Custom radiation mask fitting
- Gold marker placement (Fiducials)
- MRI Simulation Scan
- PET-CT Simulation Scan
- Radiation Therapy Alignment Tattoos
Procedures Most Often Billed to Medicare
1,515 services · 546 patients · 13 distinct codes
| Procedure | Type | Code | Services | Compared with peers |
|---|---|---|---|---|
| Ct guidance for insertion of radiation therapy fields | Imaging | 77014 |
356 | As often as other peers in Radiation Oncology |
| Design and construction of complex radiation treatment device | Imaging | 77334 |
304 | More than most peers in Radiation Oncology |
| Radiation treatment management, 5 treatment sessions | Imaging | 77427 |
234 | More often than most peers in Radiation Oncology |
| Calculation of radiation therapy dose | Imaging | 77300 |
219 | As often as other peers in Radiation Oncology |
| 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 | Imaging | 77290 |
77 | More than most peers in Radiation Oncology |
| Complex radiation therapy planning | Imaging | 77263 |
48 | As often as other peers in Radiation Oncology |
| 3d radiation therapy planning | Imaging | 77295 |
46 | More often than most peers in Radiation Oncology |
| Obtaining data needed to develop the optimal radiation treatment, 1 treatment area | Imaging | 77280 |
23 | As often as other peers in Radiation Oncology |
| Simple radiation therapy planning | Imaging | 77261 |
22 | Too few peers to compare |
| Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more | Office visit | 99214 |
107 | More often than most peers in Radiation Oncology |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Related specialists at this location 3
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
More connections — 24 related providers in 3 groups
Trained at University of Southern California Keck School of Medicine 8
Other providers in the same specialty who trained at the same institution.
Class of 1989 at University of Southern California Keck School of Medicine 8
Providers who graduated from the same medical school in the same year.
Also performs Ct guidance for insertion of radiation therapy fields 8
Providers in CA who bill this service to Medicare most often.
Common questions
What kind of doctor is Dr. Williamson?
Dr. Williamson is a radiation oncologist in Pasadena, CA. That is the designation recorded for this NPI in the federal registry, where it is listed as “Radiation Oncology”.
NPI registry
What is Dr. Williamson's address?
Dr. Williamson is listed at 625 S Fair Oaks Ave Ste 100, Pasadena, CA 91105. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How can I make an appointment with Dr. Williamson?
The number on file is (626) 397-5149. Contact the office directly to confirm availability and scheduling.
NPI registry
What is Dr. Williamson's NPI number?
Dr. Williamson's National Provider Identifier is 1952486912. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Dr. Williamson train?
Dr. Williamson attended University of Southern California Keck School of Medicine, graduating in 1989. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Williamson been practicing?
Dr. Williamson has 37 years experience. Calculated from a graduation year of 1989, reported in the CMS National Downloadable File.
CMS public data
What procedures does Dr. Williamson perform?
According to Medicare billing data, Dr. Williamson performs imaging including ct guidance for insertion of radiation therapy fields and design and construction of complex radiation treatment device, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Williamson confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Williamson. If this is you, claiming it is free.
Guide.md
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