Clinical trial · Interventional
Comparison of Iodine-124 (I-124) and Iodine-131 (I-131) Radiopharmacokinetics in Patients Prepared With Recombinant Human TSH Injection (rhTSH)
Comparison of I-124 and I-131 Radiopharmacokinetics in Patients Who Have Well-differentiated Thyroid Cancer and Are Prepared With Recombinant Human TSH Injection (rhTSH)
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Why stopped (as posted): Institutional RDRC dissolved
Summary
Brief summary (as posted)
This research study is to compare the radiopharmacokinetics of I-124 to the radiopharmacokinetics of I-131 in patients who have well-differentiated thyroid cancer after recombinant human thyroid-stimulating hormone (rhTSH) injection. I-131 is routinely used for imaging and dosimetry for patients with well-differentiated thyroid cancer. In this study, I-124 is administered orally in capsular form, and the radiopharmacokinetics of I-124 is compared with I-131. I-124 is another isotope of iodine, which is cyclotron-produced. I-124 has multiple advantages: * Ideal Half-Life (4.2 days) for delayed imaging. * High resolution tomographic imaging. * Feasibility of quantitating lesion uptake. * Potential of dosimetry for the planning of radioiodine therapy. Voluntary patients will have I-124 dosimetry performed in addition to the I-131 dosimetry, which is planned as part of routine clinical care. I-124 dosimetry is composed of four parts: (1) two extra doses of injections of rhTSH, (2) the administration of I-124, (3) PET imaging, and (4) drawing blood samples. Patients will receive two additional injections of rhTSH. This is similar to the procedure for I-131 dosimetry. Second, they will receive I-124. I-124 is similar to I-131 except I-124 decays in a different way to emit a positron so that the PET scanner can be used for imaging. I-124 is given in the form of one or several capsules, which are taken by mouth. This is also similar to I-131. Third, PET/CT imaging is done for approximately 30 minutes to one hour on five consecutive days. Radiation from PET/CT scan is far less than what they receive from a diagnostic CT scan. For the fourth part, a technologist will draw about 5 cc from the forearm on each of the five consecutive days. This is also similar to I-131. Initially, all patients will be randomized to one of two study groups. The first group will have the I-131 dosimetry performed first followed by the I-124 dosimetry, and the second group will have the I-124 dosimetry performed first followed by the I-131 dosimetry. The risk of this study is considered very low, and the potential benefits to the patient are considered very high.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Thyroid Cancer | Malignant Thyroid Gland Neoplasm | CURATED_EXACT | 0.92 |
Interventions
Interventions (1)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Radioactive Iodine 124 | Radiation | — | UNRESOLVED |
Design
Arms and outcomes
Arms (1)
- type
- OTHER
- label
- Radiopharmacokinetics
- description
- 1-2 mCi I-124 orally, once per day, twice total 0.9mg rhTSH intravenous injection, once per day, four total After TSH stimulation with Recombinant human TSH (rhTSH) for 2 days, a dose of radioactive iodine 124 ( I-124) 1.7 mCi is administrated orally and PET imaging is done for 5 continuous days including the day of the dose administration. On each day, just before imaging, 5 ml of blood is drawn. Patients will be randomized to either the sequence above (e.g. I-131 followed by I-124) or to the reverse sequence in which the I-124 is given first followed by the I-131. If I-124 is administered first and as long as the whole body retention is \< 2% by the start of the second rhTSH stimulation, the I-124 will not interfere with the I-131.
- interventionNames
- Radiation: Radioactive Iodine 124
Primary outcomes (1)
- measure
- Compare the measurement of radioiodine uptake and clearance in suspected metastatic foci of well-differentiated thyroid cancer
- timeFrame
- 2 years
Eligibility
Eligibility (as posted)
- Sex
- All
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion Criteria: * 18 years or older * Well-differentiated thyroid carcinoma * Referred for I-131 dosimetry * Preparation with Recombinant Human TSH (rh TSH) Exclusion Criteria: * \< 18 years of age * Pregnancy or breast feeding * Inability to comply with instructions * Simultaneous participation or participation in any other research study within the last month * A body weight greater than 350 lbs * A creatinine \> 1.5 mg/ml for males and 1.4 mg/ml for females * Preparation with thyroid hormone withdrawal(THW)
References
Publications (0)
Data not yet available