Using I-124 PET/CT to find metastatic thyroid cancer

Comparison of I-124 PET/CT to I-123 Whole Body Imaging for the Diagnosis of Thyroid

This will try I-124 PET/CT scans to see if they detect metastatic thyroid cancer better than the usual I-123 or I-131 scans in people treated for differentiated thyroid cancer.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 62 (estimated)
• Ages: 13 Years and up
• Sex: All
• Sponsor: University of California, San Francisco (Academic / other)
• Drugs / interventions: radiation
• Locations: 1 site (San Francisco, California)
• Trial ID: NCT06961084 on ClinicalTrials.gov

What this trial studies

This is a single-arm prospective imaging study that gives participants an I-124 PET/CT and compares the findings to routine I-123 and post-treatment I-131 imaging obtained from the medical record. The primary aim is to measure agreement between I-124 PET and I-123/I-131 SPECT, with secondary aims including sensitivity, specificity, reclassification rate, inter-reader variability, and safety. A subset of participants will undergo additional imaging over five days for dosimetry and absorbed-dose prediction. Participants are followed by phone for up to 3–5 days to capture adverse events.

Who should consider this trial

Good fit: People aged 13 or older with histologically confirmed differentiated thyroid cancer who have had total thyroidectomy and are being evaluated for metastatic disease or planned for I-123 imaging and possible I-131 therapy are ideal candidates.

Not a fit: Patients with non-differentiated thyroid cancers (for example medullary or anaplastic), those not scheduled for I-123/I-131 imaging, or those unable to travel to or undergo PET/CT are unlikely to gain benefit from this protocol.

Why it matters

Potential benefit: If successful, I-124 PET/CT could detect metastatic thyroid cancer more accurately and help guide more precise treatment and follow-up decisions.

How similar studies have performed: Prior small studies and case series suggest I-124 PET can detect more lesions than conventional I-123/I-131 imaging, but large prospective comparative data are still limited.

Eligibility criteria

Inclusion Criteria:

1. Age \>= 13 years.
2. Histopathologically confirmed differentiated thyroid cancer, with clinical concern for metastatic disease:

   1. Metastatic disease seen on I-123 SPECT, Fluorodeoxyglucose (FDG) PET, CT scan or ultrasound.
   2. Elevated thyroglobulin in participant after total thyroidectomy.

   i. Participants with an undetectable thyroglobulin will be allowed if thyroglobulin antibodies are present.
3. Meeting criteria for one of the following two populations:

   1. American Thyroid Association (ATA) intermediate or high-risk thyroid cancer and planning on treatment using I-131.
   2. Metastatic disease on imaging (CT, MRI, ultrasound or FDG PET), and considering localized therapy such as surgery and radiation therapy.
4. Undergone total thyroidectomy.
5. Planned I-123 imaging within 45 days after enrollment.
6. Ability to understand a written informed consent document, and the willingness to sign it.

Exclusion Criteria:

1. Unlikely to comply with study procedures, restrictions and requirements and judged by the Investigator to be unsuitable for participation.
2. Known pregnancy.

Where this trial is running

San Francisco, California

• University of California, San Francisco — San Francisco, California, United States (Recruiting)

Study contacts

• Principal investigator: Thomas Hope, MD — University of California, San Francisco
• Study coordinator: Maya Aslam

Conditions Thyroid Cancer; Imaging Studies