Optimal Time for 124I PET/CT Imaging in Metastatic Differentiated Thyroid Cancer.

Background: The objective of this study was to determine the optimal time for 124I PET/CT imaging to maximize the detection of locoregional and/or distant metastases of differentiated thyroid cancer.

Methods: Differentiated thyroid cancer patients suspected of having metastatic disease were prepared with low-iodine diet and appropriate thyroid-stimulating hormone stimulation. 124I PET and low-dose localization CT were performed over 4 days after oral administration of 31.

Recombinant Human Thyroid-Stimulating Hormone Versus Thyroid Hormone Withdrawal in I PET/CT-Based Dosimetry for I Therapy of Metastatic Differentiated Thyroid Cancer.

Patients with metastatic differentiated thyroid cancer (DTC) may be prepared using either thyroid-stimulating hormone withdrawal (THW) or recombinant human thyroid-stimulating hormone (rhTSH) injections before I administration for treatment. The objective of this study was to compare the absorbed dose to the critical organs and tumors determined by I PET/CT-based dosimetry for I therapy of metastatic DTC when the same patient was prepared with and imaged after both THW and rhTSH injections. Four DTC patients at MedStar Washington Hospital Center were first prepared using the rhTSH method and imaged by I PET/CT at 2, 24, 48, 72, and 96 h after administration of approximately 30-63 MBq of I.

Effects of Dosimetrically Guided I-131 Therapy on Hematopoiesis in Patients With Differentiated Thyroid Cancer.

Objective: The objective of the study was to evaluate the effects of dosimetrically guided I-131 prescribed activities on hematopoiesis reflected by changes in complete blood counts (CBCs).

Design: This was a retrospective analysis.

Setting: The study was conducted at an academic center.

Validation of a Simple Thyroid Cancer Dosimetry Model Based on the Fractional Whole-Body Retention at 48 Hours Post-Administration of (131)I.

Background: Standard dosimetric methods to determine the maximum tolerated activity (MTA) of (131)I for the treatment of metastatic, well-differentiated thyroid cancer (DTC) are time-consuming and require complex analysis. As a result, reliable, accurate, and simplified methods are desirable. The objective of this study was to evaluate the validity of a simple regression dosimetry model.

Do negative 124I pretherapy positron emission tomography scans in patients with elevated serum thyroglobulin levels predict negative 131I posttherapy scans?

Background: The management of patients with differentiated thyroid cancer (DTC) who have elevated serum thyroglobulin (Tg) levels and negative (131)I or (123)I scans is problematic, and the decision regarding whether or not to administer (131)I therapy (a "blind" therapy) is also problematic. While (124)I positron emission tomography (PET) imaging has been shown to detect more foci of residual thyroid tissue and/or metastases secondary to DTC than planar (131)I images, the utility of a negative (124)I PET scan in deciding whether or not to consider performing blind (131)I therapy is unknown. The objective of this study was to determine whether a negative (124)I pretherapy PET scan in patients with elevated serum Tg levels and negative (131)I or (123)I scans predicts a negative (131)I posttherapy scan.