Two devices for longitudinal emission tomography of the thyroid.

Two devices especially designed for tomographic thyroid imaging are compared on the basis of phantom experiments and four patients studies: a seven pinhole (7P) collimator and a time-coded aperture (TCA). The results of patient studies show that the 7P collimator may miss smaller abnormalities and is prone to incorrect positioning. The TCA reconstructions of patient data confirm the good performance observed in the phantom studies and demonstrate a high degree of lesion detectability. The TCA also provides higher efficiency and shorter imaging times than the 7P collimator. It is therefore concluded that TCA imaging is a promising alternative to multiple view pinhole imaging of the thyroid.