Nathan Yennumi Tonlaar, M.D.
NPI 1811284375ActiveIndividual· Radiology, Radiation Oncology· Springfield, MO
Radiology, Radiation Oncology (M.D.) in Springfield, Missouri, trained at University of Chicago, Pritzker School of Medicine (class of 2011). 193 Medicare patients in 2024, $118,995 paid; nearly all of their 312 Part D prescriptions were generic (97%). Novocure Inc. was the largest of 3 companies reporting payments in 2025, $283.42 in all, mostly food and beverage.
Overview
| NPI | 1811284375 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Jul 6, 2011 |
| Last updated in NPPES | Jun 2, 2016 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Radiology, Radiation Oncology Primary | 2085R0001X | 2016014780 | MO |
| Radiology, Radiation Oncology | 2085R0001X | 4301099423 | MI |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Radiation Oncology (MO) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 193 |
|---|---|
| Services billed | 1,511 across 31 procedure codes |
| Paid by Medicare | $118,995 |
Part D prescriptions in 2024
| Prescriptions (claims) | 312 · 338 30-day fills |
|---|---|
| Patients | 142 |
| Total drug cost | $2,356 |
| Generic share | 97% of claims |
Education and affiliations
| Medical school | University of Chicago, Pritzker School of Medicine |
|---|---|
| Graduation year | 2011 |
| Medicare specialty | Radiation Oncology |
Medical group
- Mercy Clinic Springfield CommunitiesLebanon, MO · 1,120 clinicians
Hospital affiliation
- Mercy Hospital SpringfieldSpringfield, MO
Industry payments (Open Payments)
- 2025$283.42 · 3 payments from 3 companies
- 2024$414.44 · 5 payments from 5 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Novocure Inc. | $175.00 | 1 |
| Siemens Medical Solutions USA, Inc. | $81.21 | 1 |
| Astrazeneca Pharmaceuticals LP | $27.21 | 1 |
What the 2025 payments were for
- Food and Beverage$283.42 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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