Clinical trial NCT06961084: Comparison of I-124 PET/CT for the Diagnosis of Thyroid Cancer
Official title: Comparison of I-124 PET/CT to I-123 Whole Body Imaging for the Diagnosis of Thyroid
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: PHASE2
Conditions: Thyroid Cancer
Keywords: Imaging Studies
Lead sponsor: University of California, San Francisco
Sponsor class: OTHER
First posted: 2025-05-07
Enrollment: 58
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief summary: Persons diagnosed with thyroid cancer are often treated initially with a thyroidectomy, which is followed by ablation using Iodine-131, a therapy which has been shown to be effective and safe. Imaging of metastatic thyroid cancer has been performed with whole body I-131 and Iodine 123 (I-123) imaging for many decades and use I-123 for staging studies. Iodine 124 (I-124) is a radioisotope of iodine which emits a positron and is imaged using PET (positron emission tomography). This is a single arm prospective trial that evaluates the ability of Iodine-124 (I-124) to detect metastatic thyroid cancer compared to non-interventional, usual care I-123 and I-131 images.

Detailed description: PRIMARY OBJECTIVES:

1. Reclassification rate of I-124 Positron Emission Tomography (PET) compared to I-123 Single-photon emission computed tomography (SPECT).
2. Sensitivity and specificity of I-124 PET to detect metastatic thyroid cancer compared to composite standard.

SECONDARY OBJECTIVES:

1. Inter-reader variability for I-124 PET and I-123 SPECT.
2. Safety of I-124 PET.
3. Participant level detection rate for I-124 in the overall population.
4. Participant level detection rate for I-124 in participants who have negative I-123 SPECT.
5. Comparison of lesion detection between I-124 PET and 24 hour I-123 SPECT.
6. Comparison of lesion detection between I-124 PET and post-treatment I-131 SPECT.

EXPLORATORY OBJECTIVES

1) Ability to predict lesion absorbed dose using I-124 PET/CT.

OUTLINE:

All participants will have a single PET/CT scan after administration of I-124 and will be followed for up to 3-5 days by phone for evaluation of adverse events. A subset of participants being evaluated for dosimetry will be imaged up to two additional times over five days after administration. Data from other scans for comparison will be obtained from the participant's medical record.

Eligibility criteria: Inclusion Criteria:

1. Age \>= 18 years.
2. Histopathologically confirmed differentiated thyroid cancer, with clinical concern for metastatic disease, which is based on:

   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. Planned I-123 imaging within 45 days after enrollment.
4. 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, per institutional policy.

Primary outcomes:
measure: Reclassification Rate
timeFrame: 1 day
measure: Overall sensitivity of I-124 PET to detect metastatic thyroid cancer (region)
timeFrame: 1 day
measure: Overall specificity of I-124 PET to detect metastatic thyroid cancer (region)
timeFrame: 1 day
Secondary outcomes:
measure: Inter-reader reliability (IRR) for I-124 PET
timeFrame: 1 day
measure: Proportion of participants with treatment-related adverse events
timeFrame: Up to 5 days
measure: Proportion of participants with positive I-124 PET in the overall population
timeFrame: 1 day
measure: Proportion of participants with positive I-124 PET in participants who have negative I-123 SPECT
timeFrame: 1 day
measure: The proportion of lesions characterized as positive on I-124 PET and 24 hour I-123 SPECT
timeFrame: 1 day
measure: Proportion of lesions characterized as positive on both I-124 PET and 7-day post I-131
timeFrame: 1 day
Other outcomes:
Locations:
city: San Francisco
country: United States
facility: University of California, San Francisco
state: California
Study officials:
affiliation: University of California, San Francisco
name: Thomas Hope, MD
role: PRINCIPAL_INVESTIGATOR
References: