Medicare Enrolled
Dr. Mark Williams, MD
Radiation Oncology · Bakersfield, CA
Practice pattern: Mixed Practice
— Diverse clinical practice across multiple procedure types
Low-engagement
Very High
DATA COVERAGE
Data in 4 of 4 federal sources
Measures public federal data availability — not provider quality
Informational, not a quality rating.
This page presents federal public records about Dr. Williams from CMS (NPPES, Open Payments, Medicare Provider Utilization, PECOS). It is not medical advice, an endorsement, or a judgment of clinical quality. Always consult the provider directly and a licensed clinician for medical decisions. Read methodology →
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What this data tells you about Dr. Williams
Dr. Mark Williams is a radiation oncology specialist in Bakersfield, CA, with 19 years of NPI registration. Based on federal Medicare data, Dr. Williams performed 7,281 Medicare services across 6,145 unique beneficiaries.
Between the years covered by Open Payments, Dr. Williams received a total of $116 from 2 pharmaceutical and/or device companies across 3 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.
✓ 19 years in practice
▲ Top 23% volume in CA
$116 industry payments
Medicare Practice Summary
Medicare Utilization ↗7,281
Medicare services
Top 23% in CA for radiation oncology
6,145
Unique beneficiaries
$28
Avg. Medicare payment
Medicare patients only (65+ / disabled) · How to read this →
~383 Medicare services per year of practice
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 |
|---|---|---|---|
| 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. |
1,561 | $25 | $91 |
| 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. |
774 | $28 | $110 |
| 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. |
500 | $22 | $90 |
| 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. |
407 | $25 | $91 |
| 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. |
398 | $36 | $162 |
| 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. |
396 | $26 | $95 |
| Abdominal X-ray, 1 view An X-ray image of the abdomen taken from a single angle to visualize internal structures. |
285 | $22 | $82 |
| 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. |
274 | $28 | $118 |
| 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. |
265 | $33 | $121 |
| X-ray of upper spine, 4-5 views An X-ray imaging test of the upper spine using 4 to 5 different views to visualize the bones and structures in that area. |
233 | $37 | $152 |
| Knee X-ray, 4 or more views An imaging test using X-rays to create multiple pictures of the knee joint from different angles. |
226 | $35 | $128 |
| 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. |
188 | $27 | $97 |
| 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. |
186 | $29 | $109 |
| X-ray of both hips, 3-4 views An X-ray imaging test that captures 3 to 4 views of both hip joints to visualize the bones and surrounding structures. |
171 | $38 | $146 |
| X-ray of upper spine, 2-3 views An X-ray imaging test of the upper spine using two to three different angles to visualize the bones and structures. |
144 | $29 | $114 |
| Knee X-ray, 1-2 views An X-ray imaging test of the knee joint using one to two different angles to visualize the bones and surrounding structures. |
103 | $25 | $91 |
| X-ray of middle spine, 3 views An X-ray imaging test that captures three different views of the middle section of the spine to evaluate its structure. |
94 | $28 | $105 |
| X-ray of middle spine, 2 views An X-ray imaging test that produces two views of the middle section of the spine to visualize the bones and joints. |
88 | $23 | $97 |
| X-ray of hand, 2 views An X-ray imaging test of the hand using two different angles to visualize the bones and joints. |
86 | $22 | $82 |
| Elbow X-ray, minimum 3 views An X-ray imaging test of the elbow joint that captures at least three different angles to visualize the bones and surrounding structures. |
82 | $24 | $98 |
| X-ray of thigh bone, minimum 2 views An X-ray imaging test of the thigh bone using at least two different angles to visualize the bone structure. |
66 | $27 | $95 |
| X-ray of upper spine, 6 or more views An X-ray imaging test of the upper spine using six or more separate views to capture detailed images of the bones and structures in that area. |
52 | $46 | $198 |
| X-ray of foot, 2 views An X-ray imaging test of the foot using two different angles to create pictures of the bones and joints. |
52 | $19 | $83 |
| X-ray of lower and sacral spine, minimum 6 views An X-ray imaging test that captures at least six views of the lower back and sacral spine to evaluate bone structure and alignment. |
50 | $52 | $222 |
| X-ray of lower leg, 2 views An X-ray imaging test of the lower leg using two different angles to visualize the bones and surrounding structures. |
50 | $23 | $79 |
| Paranasal sinus X-ray, minimum 3 views An X-ray imaging test of the paranasal sinuses using at least three different views to visualize the sinus cavities. |
47 | $26 | $111 |
| X-ray of shoulder, 1 view An X-ray image of the shoulder joint taken from a single angle. This imaging test is used to visualize the bones and surrounding structures of the shoulder. |
43 | $13 | $70 |
| Wrist X-ray, 2 views An X-ray imaging test of the wrist using two different angles to visualize the bones and joints. |
41 | $23 | $95 |
| Rib X-ray, 2 views An X-ray imaging test of the ribs on one side of the body using two different angles. |
40 | $24 | $91 |
| X-ray of upper arm, minimum of 2 views An X-ray imaging test of the upper arm that captures at least two different views to evaluate the bones and surrounding structures. |
38 | $25 | $84 |
| Rib X-ray, minimum 3 views An X-ray imaging test of the ribs on one side of the body. The procedure includes a minimum of three different views to capture detailed images. |
37 | $30 | $115 |
| X-ray of forearm, 2 views An X-ray imaging test of the forearm using two different angles to visualize the bones and surrounding structures. |
37 | $18 | $82 |
| X-ray of sacroiliac joint, 3 or more views An X-ray imaging test that takes three or more pictures of the joint connecting the lower spine to the hip bone. |
35 | $25 | $97 |
| Elbow X-ray, 2 views An X-ray imaging test of the elbow joint using two different angles to visualize the bones and surrounding structures. |
27 | $23 | $84 |
| X-ray for bone length assessment An X-ray image is taken to measure and evaluate the length of bones. |
25 | $37 | $115 |
| Rib X-ray, bilateral, minimum 4 views An X-ray imaging test of the ribs on both sides of the body, using at least four different views to capture detailed images. |
24 | $40 | $154 |
| X-ray of lower and sacral spine, 2-3 views with bending An X-ray imaging test of the lower back and sacrum using 2 to 3 views, including bending positions. |
21 | $25 | $157 |
| Pelvis X-ray, 1-2 views An X-ray imaging test of the pelvic area using one to two different angles to visualize the bones and joints. |
21 | $18 | $80 |
| X-ray of both knees, standing An X-ray image of both knees taken while the patient is standing to assess bone alignment and joint space under weight-bearing conditions. |
21 | $25 | $106 |
| X-ray of sacrum and tailbone, minimum of 2 views An X-ray imaging test of the sacrum and tailbone using at least two different angles to visualize the bones. |
20 | $19 | $81 |
| Chest X-ray, 1 view An X-ray image of the chest taken from a single angle. This imaging test is used to visualize the structures within the chest cavity. |
18 | $18 | $58 |
| X-ray of ankle, 2 views An X-ray imaging test of the ankle using two different angles to visualize the bones and joints. |
18 | $26 | $85 |
| X-ray of collar bone An X-ray image of the collar bone (clavicle) to evaluate its structure and alignment. |
13 | $24 | $86 |
| X-ray of finger, minimum of 2 views An X-ray imaging test of a finger using at least two different angles to visualize the bones and surrounding structures. |
13 | $23 | $92 |
| X-ray of middle and lower spine, 2 views An X-ray imaging test that captures two views of the middle and lower sections of the spine to visualize the bones and joints. |
11 | $20 | $108 |
How to read this data: This reflects Medicare patients only (typically 65+). Payment amounts are what Medicare paid the provider, not your out-of-pocket cost. A higher procedure volume generally indicates more experience with that procedure.
Industry Payment Transparency
Open Payments through 2022 ↗$116
Total received (2019-2022)
Avg $58/year across 2 years
Bottom 38% in CA for radiation oncology
2
Companies
3
Individual payments
All payments are legal and publicly reported · Not evidence of wrongdoing · How to interpret →
Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Meals & Travel
Food, beverages, travel, and lodging — typically low-value
$116 (100.0%)
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
2022
$38
2019
$78
Payments by company (2022)
Consulting
Speaking
Meals & Travel
Research
Medtronic, Inc.
$38
Top 3 companies account for 100.0% of 2022 payments
All-time payments by company (2019-2022) ›
Lilly USA, LLC
$78
Medtronic, Inc.
$38
Top 3 companies account for 100.0% of all-time payments
Associated products mentioned in payments ›
ABRE
Should you be concerned? Payments from pharmaceutical and device companies are legal and common — 57% of U.S. physicians receive at least one. They often reflect legitimate consulting, research, or education. What matters is whether a recommended drug or device appears in your doctor's payment records. If so, consider asking your doctor about it. How to interpret this data →
Most payments (100%) are for meals and travel — low-value interactions that are common across virtually all practicing physicians.
Geographic Context
Radiation oncologists within 10 mi
41
Per 100K population
4.5
County median income
$67,660
Nearest hospital
BAKERSFIELD MEMORIAL HOSPITAL
0.0 mi
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 2022 |
| 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 23% in CA), with low-engagement industry engagement, with 19 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 chest x-ray, 2 views?
Based on Medicare claims data, Dr. Williams performed 1,561 chest x-ray, 2 views services. Research suggests that higher procedure volume is often associated with better outcomes, particularly for complex procedures. Note that Medicare data only captures patients aged 65 and older, so the total practice volume across all patients is likely higher.
Does Dr. Williams receive payments from pharmaceutical companies?
Yes. Dr. Williams received a total of $116 from 2 companies across 3 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common among physicians — 57% of all U.S. physicians receive at least one industry payment. Patients may wish to ask their doctor about these relationships, especially if a recommended drug or device appears in the payment records.
How do Dr. Williams's costs compare to other radiation oncologists in Bakersfield?
Dr. Williams's average Medicare payment per service is $28. Note that these figures represent what Medicare pays, not your out-of-pocket cost, which depends on your specific insurance plan and deductible. Procedure-level data above shows both what was submitted and what Medicare paid for each service type.
What does Data Coverage mean?
Data Coverage (currently Very High for Dr. Williams) measures how much public federal data is available about a provider. It is not a quality rating. A "Very High" or "High" level means the provider has data across multiple federal sources (NPPES, PECOS, Medicare Utilization, Open Payments), indicating a long track record of practice, Medicare participation, and industry disclosure. A "Low" or "Moderate" level may simply mean the provider is newer, does not see Medicare patients, or has not received any industry payments — none of which are inherently negative. Read our full methodology →
Is this data up to date?
Each data source has its own update cycle. Provider registry data (NPPES) is updated weekly. Medicare enrollment (PECOS) is updated monthly. Medicare practice data has a ~2 year lag — the most recent available is typically 2 years prior. Industry payment data (Open Payments) is published annually, usually in June, covering the prior calendar year. We display the data date prominently on each section so you always know how current it is. See our data freshness policy →
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About this page
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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