NPIMap

Individual provider Active NPI

John K Byun, MD

  • Radiation Oncology Physician
  • Stony Brook, NY
National Provider Identifier
1528487089
Registry record updated Aug 11, 2026
On this page

Key facts

NPPES NPI Registry
Primary specialty
Radiation Oncology PhysicianTaxonomy code 2085R0001X
License
345605 Issued in NY
Practice address
101 Nicolls Rd
Stony Brook, NY 11794-0001
Phone
(631) 444-2325
NPI assigned
Apr 14, 2014
Sex
Male
Sole proprietor
No

NPPES NPI Registry

Updated by the provider on Aug 11, 2026

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 4

Specialty (taxonomy)CodeLicenseStatePrimary
Radiation Oncology Physician 2085R0001X 345605 NY Primary
Radiation Oncology Physician 2085R0001X 25MA10129400 NJ
Radiation Oncology Physician 2085R0001X C197416 CA
Radiation Oncology Physician 2085R0001X 281113 MA

Addresses

Primary practice location

101 Nicolls Rd
Stony Brook, NY 11794-0001

Mailing address

PO Box 419033
Boston, MA 02241-9033
Phone (631) 444-2325

Other practice location 1

195 Little Albany St
New Brunswick, NJ 08901-1914
Phone (732) 253-3939

Other practice location 2

300 Sierra College Dr Ste 150
Grass Valley, CA 95945-5083
Phone (530) 802-6400

Other practice location 3

300 Pasteur Dr
Stanford, CA 94305-2200
Phone (650) 723-4000

Other practice location 4

3249 Oak Park Ave
Berwyn, IL 60402-3429
Phone (708) 783-3403

Medicare participation

Medicare enrollment files
Medicare fee-for-service enrollment
Enrolled in MA, CA2 enrollments
Eligible to order & refer
  • Part B services
  • Medical equipment
  • Home health
  • Power mobility devices
  • Hospice
Green means eligible to order or refer.

Enrollment records 2

Enrollment IDStateProvider typePAC IDDetails
I20191018000161 MA Practitioner - Radiation Oncology 4486985173 Reassigns benefits to 3 organizations
I20240719002320 CA Practitioner - Radiation Oncology 4486985173 Reassigns benefits to 3 organizations

Care Compare profile

Medicare Care Compare
Specialty
Radiation Oncology
Education
Other, 2014
Medicare assignment
Accepts the Medicare-approved amount as payment in full
Telehealth
Offers telehealth services
Group practices
Stanford Health CareGroup PAC ID 6709797491, 3,152 clinicians

Practice addresses (Care Compare)

300 Pasteur Dr
Stanford, CA 94305-2200
Phone (650) 723-4000

Hospital & facility affiliations

National Provider Directory

National Provider Directory
Medicare enrollment (NPD)
Enrolled
Credentials
Doctor of Medicine

State licenses

LicenseStateTypeSpecialty
C197416CAMDRadiation Oncology Physician
25MA10129400NJMDRadiation Oncology Physician

Practice roles

OrganizationSpecialtyStatusNew patients
Grass Valley Radiation Oncology Radiation Oncology CurrentSince Oct 1, 2025 Accepting new patients
The General Hospital Corporation CurrentSince Sep 12, 2019 Accepting new patients
Stanford Health Care Radiation Oncology CurrentSince Jul 8, 2024 Accepting new patients
Stanford Health Care CurrentSince Jul 8, 2024 Accepting new patients
LPCH Medical Group Div of Lucile CurrentSince Jul 8, 2024 Accepting new patients
Stanford Health Care Current Accepting new patients
Mass General Brigham Medical Group Western Massachusetts Inc CurrentSince Dec 29, 2020 Accepting new patients
Sierra Nevada Memorial-Miners Hospital PastSince Oct 1, 2025 Accepting new patients

Locations

2001 Dwight Way
Berkeley, CA 94704
Phone (510) 204-1880

20126 Stanton Ave
Ste 101
Castro Valley, CA 94546
Phone (510) 581-0556

155 Glasson Way
Bldg 3
Grass Valley, CA 95945
Phone (530) 274-6600

300 Sierra College Dr
Ste 150
Grass Valley, CA 95945
Phone (530) 274-6600

725 Welch Rd
Palo Alto, CA 94304
Phone (650) 497-8979

875 Blake Wilbur Dr
Palo Alto, CA 94304
Phone (650) 723-7621

5725 W Las Positas Blvd
Ste 100
Pleasanton, CA 94588

2589 Samaritan Dr
San Jose, CA 95124
Phone (408) 357-1060

300 Pasteur Dr
Stanford, CA 94305
Phone (650) 498-5710

55 Fruit St
#2
Boston, MA 02114
Phone (617) 726-2967

55 Fruit St
Boston, MA 02114

30 Locust St
Northampton, MA 01060
Phone (413) 582-2000

Interoperability endpoints

  • Direct secure messaging: jbyun449184@direct.stanfordhealthcare.org
  • Direct secure messaging: jbyun741321@hisp.ehr.sutterhealth.org

Organizations & group practices 9

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

Hospital & facility affiliations 8

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

NPI Registry JSON

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1397433600000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1786406400000",
    "number": "1528487089",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 419033",
            "city": "BOSTON",
            "state": "MA",
            "postal_code": "022419033",
            "telephone_number": "631-444-2325"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "101 NICOLLS RD",
            "city": "STONY BROOK",
            "state": "NY",
            "postal_code": "117940001",
            "telephone_number": "631-444-2325"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "195 Little Albany St",
            "address_purpose": "LOCATION",
            "city": "New Brunswick",
            "state": "NJ",
            "postal_code": "089011914",
            "country_code": "US",
            "telephone_number": "732-253-3939",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "300 Sierra College Dr Ste 150",
            "address_purpose": "LOCATION",
            "city": "Grass Valley",
            "state": "CA",
            "postal_code": "959455083",
            "country_code": "US",
            "telephone_number": "530-802-6400",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "300 Pasteur Dr",
            "address_purpose": "LOCATION",
            "city": "Stanford",
            "state": "CA",
            "postal_code": "943052200",
            "country_code": "US",
            "telephone_number": "650-723-4000",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "3249 Oak Park Ave",
            "address_purpose": "LOCATION",
            "city": "Berwyn",
            "state": "IL",
            "postal_code": "604023429",
            "country_code": "US",
            "telephone_number": "708-783-3403",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "BYUN",
        "first_name": "JOHN",
        "middle_name": "K",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2014-04-14",
        "last_updated": "2026-08-11",
        "certification_date": "2026-08-11",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "2085R0001X",
            "taxonomy_group": "",
            "desc": "Radiology, Radiation Oncology",
            "state": "NY",
            "license": "345605",
            "primary": true
        },
        {
            "code": "2085R0001X",
            "taxonomy_group": "",
            "desc": "Radiology, Radiation Oncology",
            "state": "NJ",
            "license": "25MA10129400",
            "primary": false
        },
        {
            "code": "2085R0001X",
            "taxonomy_group": "",
            "desc": "Radiology, Radiation Oncology",
            "state": "CA",
            "license": "C197416",
            "primary": false
        },
        {
            "code": "2085R0001X",
            "taxonomy_group": "",
            "desc": "Radiology, Radiation Oncology",
            "state": "MA",
            "license": "281113",
            "primary": false
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

Other providers in Stony Brook, NY

Sources for this page

Verify at the official NPI Registry.