Development of a high resolution, 2D detector system for iodine-131-scintigraphy

During I-131 therapy of benign and malignant thyroid diseases, precise information about tracer distribution is helpful for patient management. However, the established Anger technique is used I-131 scintigraphy is difficult because of septal penetration inside the collimator. The aim of this study is to develop a 2D I-131 detector with high spatial resolution and patient-friendly acquisition time. The main components of the authors´ system are a position sensitive photomultiplier, BGO scintillation crystals inserted into a lead matrix, a parallel hole collimator and a translation unit to realize defined movements. Thus, the septa thickness is chosen to reduce the septa penetration significantly. Thick septa cause “dead areas” on the photomultiplier. These gaps are closed by defined movements in the projection plane. The individual scintigramms at the different measured positions are composed to produced a final image. Using the described detector geometry, a 2 mm spatial resolution in a measurement time less than 15 minutes was obtained for both hot and cold spots. Therefore the developed system is especially suited for I-131 thyroid scintigraphy