Comparison of Radiopharmaceuticals for Thyroid Scintigraphy

99mTc-pertechnetateLess expensiveTrapped but not organified
More readily availablePotentially misleading when activity is in esophagus or vessels
Shorter examination timePoor image quality when uptake is low
123I-iodideBetter for visualization of retrosternal thyroid tissueHigher cost
Yields better images when uptake is lowPotentially less convenient for delayed imaging at 24 h
Less readily available
Generally longer imaging times