The Role of Iodine-124-Positron Emission Tomography Imaging in the Management of Patients with Thyroid Cancer.

Molecular imaging is the visualization, characterization, and measurement of biologic processes at the molecular and cellular levels in human beings and other living systems. In thyroid cancer, this includes imaging iodine transport, which is active in about 80% of well-differentiated thyroid malignancies. Iodine-124 imaging with positron emission tomography (I-124-PET) is ideal for this purpose because PET provides tomographic images with spatial and contrast resolution. Because iodine-131 is the mainstay for therapy in thyroid cancer, and because success or failure of therapy depends on the degree of iodine uptake by the tumor cells, I-124-PET imaging will increasingly act as a surrogate for this treatment. This approach may serve as a model for individualized therapeutic interventions for many other malignant and nonmalignant diseases.