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RecruitingNCT03841617Updated Oct 29, 2026

The Use of 124-I-PET/CT Whole Body and Lesional Dosimetry in Differentiated Thyroid Cancer

A Phase 2 interventional study of Thyrogen and I-131 in Thyroid Cancer, sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Recruiting at 1 site in United States. Open to participants aged 18 Years to 90 Years. Per ClinicalTrials.gov, last updated 2026-10-29.

Sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Phase 2, Interventional, and Treatment

From the registry’s dates

  • Started Jul 2019; still recruiting 7 years 3 months later.
Phase
Phase 2
Study type
Interventional
Enrollment
30
Allocation
Non-randomized
Ages
18 Years to 90 Years
Sex
All
01

Study summary

Study rationale

High risk patients with differentiated thyroid cancer (DTC) require therapy with 131 I under thyroid stimulating hormone (TSH) stimulation. There are two methods of TSH stimulation endogenous by thyroid hormone withdrawal (THW) leading to hypothyroidism and exogenous by injection of human recombinant TSH (rhTSH Thyrogen). The appropriate 131-I activity utilized for treatment is either based on empiric fixed dosage choice or individually determined activity based on 131 I dosimetric calculations. Although dosimetry utilizing radioactive iodine isotope 131 I enables calculation of maximum safe dose, it does not estimate the tumoricidal activity necessary to destroy the metastatic lesions. The alternative radioactive isotope of iodine -124 I, used for positron emission tomography (PET) imaging, might be used for calculation not only the maximum safe131 I dose, but also to predict the absorbed dose in the metastatic lesions.

Study objectives

The primary objective of this study is to compare the 124 I -PET/CT lesional and whole body dosimetry in each individual patient with metastatic radioiodine (RAI)-avid thyroid cancer under preparation with rhTSH and THW. The secondary objective is to evaluate the predicted by PET/CT lesional uptake with the early response to therapy.

Study design

This is a phase 2 pilot prospective cohort study comparing the lesional and whole body dosimetry within each patient undergoing exogenous (rhTSH) and endogenous (THW) TSH stimulation and followed for 5 years.

Interventions

Each study participant will undergo rhTSH and THW-aided 124 I-PET/CT dosimetric evaluations and will be subsequently treated with THW-aided RAI activity based on dosimetric calculations enabling maximum safe dosage. The patients will be followed in 12+/-3 months intervals for 5 years.

Sample size and population

This pilot study will include 30 patients with high risk differentiated thyroid cancer presenting with distant and/or loco-regional metastases.

Read the detailed description

Study Description:

Each study participant will undergo rhTSH and THW-aided 124IPET/ CT dosimetric evaluations and will be subsequently treated with THW-aided RAI activity based on dosimetric calculations enabling maximum safe dosage.

Objectives:

Primary objective: To compare the 124I -PET/CT lesional and whole body dosimetry in each individual patient with metastatic radioiodine (RAI)-avid thyroid cancer under preparation with rhTSH and THW.

Secondary objective: To evaluate the predicted by PET/CT lesional uptake with the early response to therapy.

Endpoints:

Primary Endpoint: The predicted radiation dose measured as rads per lesion compared per each measurable lesion between the dose calculated under rhTSH and under THW.

Secondary Endpoints: Area under the curve analyzing the association of dose per lesion measured in rads and objective response to treatment at 1, 2, 3, 4, 5 years landmarks.

02

Conditions studied

  • Thyroid Cancer

Keywords

  • Thyroid Cancer
  • PET/CT
  • 124-I
  • Radioiodine
  • Metastases
03

In context

Thyroid Neoplasms

785 studies on the registry are indexed under Thyroid Neoplasms; 204 are open to participants now.

This study's planned enrollment of 30 is below the median of 53 across 520 interventional studies indexed under Thyroid Neoplasms.

Browse Thyroid Neoplasms studies →

Lead sponsor

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is the lead sponsor of 538 studies on the registry; 55 are open to participants now.

Of its 80 completed or terminated interventional studies of FDA-regulated products, 51 (64%) have results posted.

Browse National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 90 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Patients with established thyroid cancer diagnosis based on the pathology report reviewed at the National Institutes of Health, who:

    • underwent total thyroidectomy plus or minus neck lymph node dissection as clinically indicated,
    • are presenting with known per structural imaging (US neck, CT or MRI neck/chest/abdomen/pelvis) persistent/recurrent disease either locally advanced or presenting with distant ; or
    • are presenting with suspected persistent/recurrent locoregional or distant metastases based on the high risk features such as advanced tumor per pathology report (tumor size >4 cm, exrathyroidal extension, higher risk pathology such as tall cell, columnar cell, poorly differentiated variant, follicular thyroid cancer with gross vascular invasion, positive margins after the surgery, bulky lymphadenopathy in the central and/or lateral neck), detectable/increasing baseline/suppressed thyroglobulin (Tg) level or detectable/increasing anti-Tg antibody titers if anti-Tg antibodies are present.
    • are either RAI -naive or requiring repeated RAI therapy for locally advanced disease or distant metastases or underwent therapy with BRAF inhibitor (dabrafenib or vemurafenib*) or selumetinib** for at least 4 weeks that may re-induce RAI uptake.

    • Underwent imaging with either a CT or MRI of the brain and spine with gadolinium contrast to screen for the brain/spine metastases.

      • Age greater than or equal to 18 years of age.

      • 24 hour urine iodine excretion of less than or equal to 150 micro grams/24 hour.

        • BRAF inhibitors are recommended by 2021 NCCN guidelines as one of the management options for BRAF mutant tumors(13,14)

          • Selumetinib has an FDA orphan drug designation for treatment of metastatic thyroid cancer to re-induce RAI uptake

Exclusion criteria

EXCLUSION CRITERIA:

-Patients with RAI-non avid disease documented by negative post-therapy whole body scans performed after previous RAI treatments and not subjected to re-differentiation therapy.

  • Serious underlying medical conditions that restrict diagnostic testing or therapy such as renal failure, congestive cardiac failure or active coexisting non-thyroid carcinoma, severe depression which might be exacerbated by thyroid hormone withdrawal.

  • Patients with spinal or as they are at risk of TSH-stimulation induced swelling of lesions leading to potentially detrimental side effects. These patients will be evaluated per the standard of care protocol 77-DK-0096.

    • Pregnant or lactating women per self report.
    • Adults who are incapable of providing .
Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

Adjuvant and neoadjuvant

Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Crossover assignment
Masking
None (open label)
Enrollment
30 participants (estimated)

Study arms

  • Active comparator
    124I PET/CT scan after rhTSH

    124I PET/CT scan after preparation with human recombinant TSH

    Drug: Thyrogen · Radiation: I-131 · Radiation: I-124

  • Active comparator
    124I PET/CT scan after thyroid hormone withdrawal

    124I PET/CT scan after preparation with thyroid hormone withdrawal

    Radiation: I-131 · Radiation: I-124 · Other: Thyroid hormone withdrawal

Interventions

  • DrugThyrogen

    intramuscular injection administered once/day for 2 consecutive days at Week 3; then once annually for subjects who meet criteria.

  • RadiationI-131

    therapeutic dose administered orally to treat thyroid cancer at Week 8. 5-7 days later, the post-treatment I-131 Whole Body scan w/ SPECT is performed; then administered once annually, if the patient needs to be re-treated

  • RadiationI-124

    one capsule ingested orally once at Week 3, and Week 8; then administered once annually to subjects who meet criteria.

  • OtherThyroid hormone withdrawal

    withdrawal of thyroid hormone during weeks 4 through 8

06

What researchers measure

Primary outcomes

  1. Comparison of the whole body and lesional 124I uptake within each patient prepared for imaging with human recombinant TSH (rhTSH) and thyroid hormone withdrawal (THW)

    Whole body and lesional uptake of 124I calculated after preparation with human recombinant TSH (rhTSH) compared to dosimetry calculated after preparation using thyroid hormone withdrawal (THW)

    Time frame: 9 weeks

07

Study locations

1 of 1 sites recruiting
  • National Institutes of Health Clinical Center
    Bethesda, Maryland 20892, United States
    Recruiting
    • For more information at the NIH Clinical Center contact Office of Patient Recruitment (OPR) · Contactprpl@cc.nih.gov · 800-411-1222
08

References and documents

Individual participant data

Plan to share: No — Subject level data will be shared upon request after appropriate collaboration agreements are in place.

09

Timeline

2 registry updates since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Jul 2019 (actual). Primary completion is estimated for Nov 2035, 195 months after the start.

Of 77 non-industry phase 2 interventional studies under Thyroid Neoplasms, half reached primary completion within 84 months of starting (the median), counting those still running; a quarter within 50 and three quarters within 124. This study's planned 195 months is above that.

Counting every sponsor, half of 92 studies reached it within 73 months; a quarter within 39 and three quarters within 119.

How these figures are worked out, and which studies are left out of them.

Registered
Feb 13, 2019
First posted
Feb 15, 2019
StartActual
Jul 29, 2019
Primary completionEst.
Nov 1, 2035
CompletionEst.
Nov 1, 2035
Last update
Oct 29, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Minor edits
Nothing that changes what the study is or who can join. Edited: description and verification date
2 updates, last Oct 29, 2026
Show all 2 updates
  1. Oct 29, 2026
    Minor edits only
    + 2 other changes: verification date and description
  2. Oct 26, 2026
    Minor edits only
    + 1 other change: description

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT03841617
Lead sponsor
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Responsible party
Sponsor
First posted
Feb 15, 2019
Start date
Jul 29, 2019
Primary completion
Nov 1, 2035 (estimated)
Completion
Nov 1, 2035 (estimated)
Last update
Oct 29, 2026

Study contacts

Padmasree Veeraraghavan, R.N.
Contact
padmasree.veeraraghavan@nih.gov
(301) 451-7710
Joanna Klubo-Gwiezdzinska, M.D.
Contact
joanna.klubo-gwiezdzinska@nih.gov
(301) 496-5052
Joanna Klubo-Gwiezdzinska, M.D.
principal investigator · National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Oversight

FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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