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

During a I-131 therapy of benign and malignant thyroid diseases, precise in formation about tracer distribution is helpful for patient management. Howe ver, the use of established Anger technique for I-131 scintigraphy is diffi cult because of septal penetration inside the collimator. The aim of this s tudy is to develop a two-dimensional I-131 detector with high spatial resol ution and patient-friendly acquisition time. The main components of our system are a position sensitive photomultiplier, EGO scintillation crystals inserted into a lead matrix, a parallel hole co llimator and a translation unit to realize well defined displacements. Thus , the septa thickness can be chosen to reduce the septa penetration signifi cantly. Thick septa cause "dead areas" on the photomultiplier. These gaps a re filled sequentially by well defined displacements in the projection plan e. The individual scintigramms at the different measured positions are comp osed to a final image. Using the described detector geometry, all details and structures of the me asured phantom were visible in a measurement time of 16 minutes. Therefore the developed system is especially suited for I-131 thyroid scintigraphy.