Doctor profile · Federal record

Dr. Nathan Tonlaar, M.D.

Radiation Oncology Physician (CMS: Radiation Oncology) · Radiation Oncology Physician · Springfield, MO

  • NPI 1811284375
  • Accepts Medicare
  • 15 yrs in practice
  • Licensed in 2 states
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
2055 S Fremont Ave, Mercy Clinic Radiation Oncology, Chaub O'Reilly Center
Springfield, MO 658042206
(417) 820-2468
fax (417) 820-7794

Credentials & registration

NPPES · NUCC
NPI registered
July 2011 — 15 yrs on file
Profile last updated
June 2, 2016
Year of graduation
2011 — 15 yrs since
Specialty taxonomy
2085R0001X — NUCC code
State licenses (2)
Missouri #2016014780 · Michigan #4301099423

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1811284375. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
1,317
Distinct HCPCS
10
Medicare allowed
$127,808
HCPCS Description Services Patients Avg allowed
77014 Ct guidance for insertion of radiation therapy fields 518 71 $43
77334 Design and construction of complex radiation treatment device 167 72 $58
77427 Radiation treatment management, 5 treatment sessions 140 57 $182
77300 Calculation of radiation therapy dose 115 43 $32
77263 Complex radiation therapy planning 76 71 $162
99205 New patient office or other outpatient visit, 60-74 minutes 54 54 $173
77301 High precision radiation therapy planning 34 33 $403
77338 Design and construction of radiation treatment device for high precision radiation therapy 34 33 $216
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 30 26 $79
99215 Established patient office or other outpatient visit, 40-54 minutes 22 17 $137

In context: peer comparison

Among 4 peers in Springfield Radiation Oncology Physician, average services per provider: 144. This provider delivers 9.1× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$414
Transactions
5
Manufacturers
5
Payer (manufacturer) Industry Txns Amount
Tempus Ai, INC 1 $113.89
Medtronic, INC. 1 $104.85
Novocure INC. 1 $93.39
Siemens Medical Solutions USA, INC. 1 $86.79
Janssen Biotech, INC. 1 $15.52

By nature of payment

Food and Beverage
$414

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
180
Patients
159
Total drug cost
$1,521
Drug Type Claims Patients Total cost
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 54 49 $478
Levofloxacin Generic 38 38 $81
Diazepam Generic 32 29 $23
Tamsulosin Hcl Generic 26 18 $407
Ondansetron Odt (Ondansetron) Brand 16 12 $228
Dexamethasone Generic 14 13 $303

Frequently asked questions

Auto-generated from federal data
What is Dr. Nathan Tonlaar's medical specialty?
Dr. Nathan Tonlaar practices Radiation Oncology Physician in Springfield, MO.
Where does Dr. Nathan Tonlaar practice?
Dr. Nathan Tonlaar practices at 2055 S Fremont Ave, Springfield, MO 658042206. Office phone: 4178202468.
What is Dr. Nathan Tonlaar's NPI?
Dr. Nathan Tonlaar's National Provider Identifier (NPI) is 1811284375, issued by NPPES.
Does Dr. Nathan Tonlaar accept Medicare assignment?
Yes. Dr. Nathan Tonlaar accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. Nathan Tonlaar commonly perform?
Top Medicare-reported procedures in 2023: Ct guidance for insertion of radiation therapy fields (HCPCS 77014); Design and construction of complex radiation treatment device (HCPCS 77334); Radiation treatment management, 5 treatment sessions (HCPCS 77427). Source: CMS Medicare Physician & Other Practitioners file.