Dr. Symphorosa Williams, M.D.
What this data tells you about Dr. Williams
Dr. Symphorosa Williams is a radiation oncology specialist in La Jolla, CA, with 20 years of NPI registration. Based on federal Medicare data, Dr. Williams performed 4,984 Medicare services across 2,664 unique beneficiaries.
Between the years covered by Open Payments, Dr. Williams received a total of $372 from 8 pharmaceutical and/or device companies across 11 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common in radiation oncology. Most payments are for meals and travel — low-value interactions common across virtually all practicing physicians. Patients may wish to discuss these relationships with their provider.
The Data Coverage level for Dr. Williams is Very High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
Medicare Practice Summary
Medicare Utilization ↗Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| MRI contrast dye injection (gadoterate) Administration of gadoterate meglumine, a contrast agent, in a 0.1 ml dose. |
2,280 | $0 | $1 |
| Screening mammography An X-ray of the breast used to detect breast cancer in women who have no signs or symptoms of the disease. |
739 | $146 | $748 |
| 3D screening mammography (tomosynthesis) A screening imaging test of the breast using 3D technology to detect potential abnormalities. |
710 | $58 | $297 |
| Digital breast tomosynthesis (3D mammogram) A specialized imaging test that creates three-dimensional pictures of the breast tissue to help detect abnormalities. |
152 | $45 | $148 |
| Bone density scan (DEXA) A test that uses low-dose X-rays to measure bone mineral density in the hip, pelvis, and spine. It helps assess bone strength and risk of fractures. |
148 | $24 | $122 |
| Complete breast ultrasound, 1 breast A complete ultrasound examination of one breast to visualize internal structures. |
117 | $83 | $870 |
| Diagnostic mammography of 1 breast An X-ray examination of one breast to evaluate specific breast symptoms or abnormalities. |
109 | $105 | $733 |
| Diagnostic mammography of both breasts | 83 | $129 | $926 |
| Technetium Tc-99m tetrofosmin diagnostic injection A diagnostic injection of Technetium Tc-99m tetrofosmin used for imaging studies. |
62 | $76 | $389 |
| Fluorodeoxyglucose f-18 fdg, diagnostic, per study dose, up to 45 millicuries | 51 | $281 | $875 |
| Nuclear medicine scan from skull base to mid-thigh with CT A nuclear medicine imaging study covering the area from the base of the skull to the middle of the thighs, performed alongside a CT scan. |
48 | $1,456 | $9,375 |
| Knee X-ray, 4 or more views An imaging test using X-rays to create multiple pictures of the knee joint from different angles. |
38 | $37 | $449 |
| Limited ultrasound of 1 breast A focused ultrasound examination of a single breast to evaluate specific areas of concern. |
38 | $62 | $542 |
| X-ray of lower and sacral spine, 2-3 views An X-ray imaging test that captures 2 to 3 views of the lower back and sacral spine to visualize the bones and joints in this area. |
34 | $27 | $197 |
| Foot X-ray, 3+ views An X-ray imaging test of the foot that captures at least three different views to evaluate the bones and joints. |
32 | $24 | $219 |
| Nuclear stress test of heart muscle A nuclear medicine imaging test that evaluates blood flow to the heart muscle at rest and during stress using a special camera. |
31 | $373 | $2,645 |
| Shoulder X-ray, 2+ views An X-ray imaging test of the shoulder joint using at least two different angles to visualize the bones and surrounding structures. |
29 | $28 | $201 |
| Hip X-ray, 2-3 views An X-ray imaging test of the hip joint using two to three different angles to visualize the bones and surrounding structures. |
29 | $32 | $247 |
| Wrist X-ray, minimum 3 views An imaging test using X-rays to capture at least three different angles of the wrist bones and joints. |
27 | $31 | $244 |
| Knee X-ray, 3 views An X-ray imaging test of the knee joint that captures three different angles to evaluate the bones and surrounding structures. |
26 | $29 | $188 |
| Chest X-ray, 2 views An X-ray imaging test of the chest that captures two different angles to visualize the lungs, heart, and chest wall. |
22 | $11 | $75 |
| X-ray of lower and sacral spine, minimum of 4 views An X-ray imaging test of the lower back and sacrum using at least four different angles to visualize the bones and joints. |
22 | $36 | $279 |
| Rubidium rb-82, diagnostic, per study dose, up to 60 millicuries | 21 | $408 | $1,823 |
| MRI scan of both breasts A magnetic resonance imaging test that creates detailed pictures of both breasts to help evaluate breast tissue. |
20 | $266 | $1,733 |
| X-ray of surgical specimen | 18 | $13 | $82 |
| X-ray of hand, minimum of 3 views An X-ray imaging test of the hand that captures at least three different angles to visualize the bones and joints. |
17 | $19 | $180 |
| Ankle X-ray, minimum 3 views An X-ray imaging test of the ankle that captures at least three different angles to evaluate the bones and joints. |
17 | $32 | $205 |
| Exercise or drug-induced heart stress test with ECG A heart stress test performed using exercise or medication while an electrocardiogram is monitored under physician supervision. |
16 | $14 | $80 |
| Breast biopsy with localization device using X-ray A procedure to remove a sample of breast tissue for testing, using X-ray guidance to place a device that marks the location of the first growth. |
13 | $443 | $2,085 |
| X-ray for bone length assessment An X-ray image is taken to measure and evaluate the length of bones. |
12 | $41 | $263 |
| Whole body nuclear medicine scan with CT A combined imaging procedure using nuclear medicine and CT scans to visualize the entire body. |
12 | $1,467 | $9,381 |
| Nuclear medicine bone and joint scan A nuclear medicine imaging test that uses a radioactive tracer to examine multiple areas of the bones and joints. |
11 | $30 | $209 |
Industry Payment Transparency
Open Payments through 2024 ↗Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
Payments by company (2024)
All-time payments by company (2018-2024) ›
Associated products mentioned in payments ›
Most payments (100%) are for meals and travel — low-value interactions that are common across virtually all practicing physicians.
Geographic Context
0.0 mi
Data Sources
| Provider Registry | ✓ NPPES | Weekly updates |
| Medicare Enrollment | ✓ PECOS | Monthly updates |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not public | N/A |
This provider has data in 4 of 4 available federal datasets, with a Data Coverage level of Very High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Williams is a mixed practice specialist, with above-average Medicare volume (top 30% in CA), with low-engagement industry engagement, with 20 years of NPI registration.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
Is Dr. Williams experienced with mri contrast dye injection (gadoterate)?
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All data on this page is sourced verbatim from public federal records published by the U.S. Centers for Medicare & Medicaid Services (CMS): NPPES ↗, Open Payments ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
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