Comparison of Iodine-124 (I-124) and Iodine-131 (I-131) Radiopharmacokinetics
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.
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacokinetics Study
Intervention Model: Single Group Assignment
Masking: Open Label
|Official Title:||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)|
- Compare the measurement of radioiodine uptake and clearance in suspected metastatic foci of well-differentiated thyroid cancer [ Time Frame: 2 years ] [ Designated as safety issue: No ]
|Study Start Date:||December 2008|
|Estimated Study Completion Date:||August 2012|
|Estimated Primary Completion Date:||July 2012 (Final data collection date for primary outcome measure)|
Radiation: Radioactive Iodine 124
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.
|Contact: Dougals Van Nostrand, MD||202 877 email@example.com|
|Contact: Boris A Frolov, MD||202 877 firstname.lastname@example.org|
|United States, District of Columbia|
|Washington Hospital Center||Recruiting|
|Washington, District of Columbia, United States, 20010|
|Contact: Douglas Van Nostrand, MD 202-877-0348 email@example.com|
|Contact: Boris A Frolov, MD 202 877 6094 firstname.lastname@example.org|
|Principal Investigator:||Douglas Van Nostrand, MD||Director, Nuclear Medicine|