An integrated PET–SPECT imager for small animals

We have built the YAP–PET tomograph: an integrated PET–SPECT imager for performing in vivo studies on new radiopharmaceuticals and tumor therapy evaluation in small animals. The field of view is 4 cm axially and 4 cm in diameter. The scanner is made of four detector modules that can rotate up to 360°. Each detector is composed of a YAP:Ce matrix (20×20 match like crystals of dimensions 2×2×30 mm3) coupled to a position-sensitive photomultiplier (Hamamatsu R2486-06). Two opposite detectors are equipped with high-resolution lead collimators (0.6 mm hexagonal holes, 0.15 mm septa thickness, and 20 mm thick). The collimators are easily mountable and removable from the detector heads, so as to obtain a two-head PET combined with a two-head SPECT, or a four-head PET scanner.