Gregory Lee Thalken, MD

Primary specialty

Diagnostic Radiology PhysicianTaxonomy code 2085R0202X

License

C162624 Issued in CA

Practice address

2801 Atlantic Ave
Long Beach, CA 90806-1701

Phone

(562) 933-1550

NPI assigned

Jan 24, 2007

Last updated

May 6, 2026By the provider in NPPES

Sex

Male

Sole proprietor

No

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

Specialties & licenses 1

Addresses

Electronic endpoints 1

Medicare fee-for-service enrollment

Enrolled in MS, MN, CA, NJ, NV, HI, LA, KY, IN, OR, AR, IL, TX, AL, PA, OH, MI, AZ, TN19 enrollments

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 19

Specialty

Diagnostic Radiology

Education

Other, 2006

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Fullerton Radiology Medical Group IncGroup PAC ID 4587632575, 55 clinicians

Capital Health Multispecialty GroupGroup PAC ID 1850689894, 342 clinicians

University of Arkansas for Medical SciencesGroup PAC ID 4082528955, shared by 29 NPIs, 1,159 clinicians

Arkansas Health GroupGroup PAC ID 7911802079, 645 clinicians

Lompoc Valley Medical CenterGroup PAC ID 9739275595, 90 clinicians

Inspira Health Network Medical Group PCGroup PAC ID 4880797570, 238 clinicians

Ochsner Clinic LLCGroup PAC ID 8224933619, 2,845 clinicians

Medical Foundation IncGroup PAC ID 9234043712, 211 clinicians

Hawaii Diagnostic Radiology Services LLCGroup PAC ID 0547253221, 16 clinicians

Insight Chicago IncGroup PAC ID 2860894706, 140 clinicians

Memorialcare Medical FoundationGroup PAC ID 8729277314, 555 clinicians

Universal Radiology Partners of California PCGroup PAC ID 7214372986, 67 clinicians

County of San JoaquinGroup PAC ID 6002703436, 199 clinicians

Renaissance Medical FoundationGroup PAC ID 1153409867, 178 clinicians

Placerville Radiology Medical Group IncGroup PAC ID 0143382374, 62 clinicians

Rockford Radiology AssocGroup PAC ID 1254330749, 43 clinicians

West Valley Radiology Medical Group IncGroup PAC ID 1658266622, 42 clinicians

Integrated Imaging Consultants LLCGroup PAC ID 2567784408, 163 clinicians

NRHS Radiology AssociatesGroup PAC ID 2668555731, 61 clinicians

Valley Physician Services PCGroup PAC ID 3577857333, 593 clinicians

Los Alamitos Radiology Group IncGroup PAC ID 5092718882, 69 clinicians

X-Ray Associates of Port Huron P CGroup PAC ID 5395789531, 28 clinicians

Radx Imaging Partners IncGroup PAC ID 5698113041, 46 clinicians

Peninsula Radiological Associates LimitedGroup PAC ID 5991603573, 64 clinicians

Washington Radiologists Medical Group IncGroup PAC ID 6305927245, 66 clinicians

Focus Medical ImagingGroup PAC ID 6406999259, 95 clinicians

Menalam Health Services PCGroup PAC ID 7012319163, 89 clinicians

Santa Cruz Radiology L L CGroup PAC ID 7012996952, 46 clinicians

Eastpointe Radiologists PCGroup PAC ID 7618876327, 112 clinicians

San Antonio Radiological MedicalGroup PAC ID 8325035942, 54 clinicians

Central Valley Imaging Medical Associates IncGroup PAC ID 8628064953, 87 clinicians

Radiology Group PC SCGroup PAC ID 9032008537, 39 clinicians

Oklahoma Radiology Group P CGroup PAC ID 9032101688, 59 clinicians

Kennewick Radiology Group PCGroup PAC ID 9335230549, 34 clinicians

Ecm Health Group LLCGroup PAC ID 9436395225, 139 clinicians

Sutter Valley Medical FoundationGroup PAC ID 9830094515, 2,473 clinicians

Universal Radiology Partners of NevadaGroup PAC ID 5799295259, 71 clinicians

McLaren Hospital GroupGroup PAC ID 2365968351, 366 clinicians

Temple Faculty Practice Plan IncGroup PAC ID 0345588711, 1,325 clinicians

Erlanger HealthGroup PAC ID 1153780226, 504 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Washington Hospital Hospital, Fremont, CA, CCN 050195
• Baptist Health Medical Center-Little Rock Hospital, Little Rock, AR, CCN 040114
• Memorial Medical Center Hospital, Modesto, CA, CCN 050557
• Marshall Medical Center Hospital, Placerville, CA, CCN 050254
• Temple Health - Chestnut Hill Hospital Hospital, Philadelphia, PA, CCN 390026

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles (60 of 136)

Locations (25 of 145)

Networks

• BSC 65 PLUS INDIVIDUAL MAPD

Interoperability endpoints

• Direct secure messaging: gregory.thalken.p1@direct.wcchc.nextgenshare.com
• Direct secure messaging: gthalken1155429@direct.hfhs.org
• Direct secure messaging: gthalken151506@direct.whhs.com
• Direct secure messaging: gthalken364187@scrippshlth.medalliesdirect.net

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

• Central Valley Imaging Medical Associates, Inc

  • Diagnostic Radiology Physician
  • Manteca, CA
  • NPI 1275523169

  MN

  Medicare reassignment Care Compare group NPD
• County of San Joaquin

  dba San Joaquin General Hospital

  • General Acute Care Hospital
  • French Camp, CA
  • NPI 1801830583
  Medicare reassignment Care Compare group NPD
• Focus Medical Imaging

  • Diagnostic Radiology Physician
  • Monrovia, CA
  • NPI 1528299989

  MN

  Medicare reassignment Care Compare group NPD
• Fullerton Radiology Medical Group, Inc

  • Diagnostic Radiology Physician
  • Anaheim, CA
  • NPI 1861451858

  MN

  Medicare reassignment Care Compare group NPD
• Lompoc Valley Medical Center

  • General Practice Physician
  • Lompoc, CA
  • NPI 1649282856

  Family Medicine

  Medicare reassignment Care Compare group NPD
• Los Alamitos Radiology Group Inc

  • Diagnostic Radiology Physician
  • Los Alamitos, CA
  • NPI 1427005024

  MN

  Medicare reassignment Care Compare group NPD
• Menalam Health Services PC

  • Diagnostic Radiology Physician
  • Glendora, CA
  • NPI 1003779596

  MN

  Medicare reassignment Care Compare group NPD
• Placerville Radiology Medical Group Inc

  • Diagnostic Radiology Physician
  • Placerville, CA
  • NPI 1700847621

  MN

  Medicare reassignment Care Compare group NPD
• Radx Imaging Partners Inc

  • Diagnostic Radiology Physician
  • Hollister, CA
  • NPI 1366146755

  MN

  Medicare reassignment Care Compare group NPD
• San Antonio Radiological Medical

  • Diagnostic Radiology Physician
  • Upland, CA
  • NPI 1457396947

  MN

  Medicare reassignment Care Compare group NPD
• Universal Radiology Partners of California PC

  • Diagnostic Radiology Physician
  • Temecula, CA
  • NPI 1467225235
  Medicare reassignment Care Compare group NPD
• Washington Radiologists Medical Group, Inc.

  • Specialist
  • Fremont, CA
  • NPI 1851355622

  MN

  Medicare reassignment Care Compare group NPD

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

• Marshall Medical Center

  • General Acute Care Hospital
  • Placerville, CA
  • NPI 1972503142
  Care Compare affiliation
• Sutter Valley Hospitals

  dba Memorial Medical Center

  • General Acute Care Hospital
  • Modesto, CA
  • NPI 1699129601
  Care Compare affiliation
• Washington Township Hospital District

  dba Washington Hospital

  • General Acute Care Hospital
  • Fremont, CA
  • NPI 1780614685
  Care Compare affiliation
• Baptist Health

  dba Baptist Health Medical Center-Little Rock

  • General Acute Care Hospital
  • Little Rock, AR
  • NPI 1043240682
  Care Compare affiliation
• CHH Community Health

  dba Chestnut Hill Hospital - Temple Health

  • General Acute Care Hospital
  • Philadelphia, PA
  • NPI 1437865953
  Care Compare affiliation

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

{
    "created_epoch": "1169596800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1778025600000",
    "number": "1861547317",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "2801 ATLANTIC AVE",
            "city": "LONG BEACH",
            "state": "CA",
            "postal_code": "908061701",
            "telephone_number": "562-933-1550"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "2801 ATLANTIC AVE",
            "city": "LONG BEACH",
            "state": "CA",
            "postal_code": "908061701",
            "telephone_number": "562-933-1550"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "500 Martha Jefferson Dr",
            "address_purpose": "LOCATION",
            "city": "Charlottesville",
            "state": "VA",
            "postal_code": "229114668",
            "country_code": "US",
            "telephone_number": "434-654-7000",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "6125 Ranier Ln N",
            "address_purpose": "LOCATION",
            "city": "Plymouth",
            "state": "MN",
            "postal_code": "554462072",
            "country_code": "US",
            "telephone_number": "858-546-3800",
            "fax_number": "858-546-3900",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "750 Brunswick Ave",
            "address_purpose": "LOCATION",
            "city": "Trenton",
            "state": "NJ",
            "postal_code": "086384143",
            "country_code": "US",
            "telephone_number": "609-394-6000",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "310 Salem Woodstown Rd",
            "address_purpose": "LOCATION",
            "city": "Salem",
            "state": "NJ",
            "postal_code": "080792064",
            "country_code": "US",
            "telephone_number": "856-935-1000",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "4301 W Markham St # 556",
            "address_purpose": "LOCATION",
            "city": "Little Rock",
            "state": "AR",
            "postal_code": "722057101",
            "country_code": "US",
            "telephone_number": "501-296-1095",
            "fax_number": "501-526-5919",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "2010 Health Campus Dr",
            "address_purpose": "LOCATION",
            "city": "Rockingham",
            "state": "VA",
            "postal_code": "228018679",
            "country_code": "US",
            "telephone_number": "540-432-8950",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "4440 W 95th St",
            "address_purpose": "LOCATION",
            "city": "Oak Lawn",
            "state": "IL",
            "postal_code": "604532600",
            "country_code": "US",
            "telephone_number": "708-684-8000",
            "fax_number": "708-520-1039",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "1 Capital Way",
            "address_purpose": "LOCATION",
            "city": "Pennington",
            "state": "NJ",
            "postal_code": "085342520",
            "country_code": "US",
            "telephone_number": "609-303-4000",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "THALKEN",
        "first_name": "GREGORY",
        "middle_name": "LEE",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2007-01-24",
        "last_updated": "2026-05-06",
        "certification_date": "2026-05-06",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "2085R0202X",
            "taxonomy_group": "",
            "desc": "Radiology, Diagnostic Radiology",
            "state": "CA",
            "license": "C162624",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [
        {
            "endpointType": "FHIR",
            "endpointTypeDescription": "FHIR URL",
            "endpoint": "https://memorialcare.org/fhir/api/FHIR/R4/",
            "affiliation": "Y",
            "endpointDescription": "MemorialCare FHIR Endpoint",
            "affiliationName": "MemorialCare Medical Foundation",
            "use": "HIE",
            "useDescription": "Health Information Exchange (HIE)",
            "contentType": "OTHER",
            "contentTypeDescription": "Other",
            "contentOtherDescription": "FHIR",
            "address_1": "17360 Brookhurst St",
            "city": "Fountain Valley",
            "state": "CA",
            "country_code": "US",
            "postal_code": "927083720",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "other_names": []
}

• Maija Thackerson, L.P.T.
• Alison H Thai, PHARMD
• Marlin Thai, PHARM.D.
• Nam Khanh Thai, MD
• Bhavik V Thakkar, MD
• Margaret Tham
• Wachira Thanaphinyokul-Ripple
• Kati Thantrong
• Ilene Han Thaopraseuth
• Subita Thapa

• Diagnostic Radiology Physician in Long Beach, CA
• Providers in Long Beach, CA by specialty
• Diagnostic Radiology Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on May 6, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.