Heart imaging by cadmium telluride gamma camera European Program "BIOMED" consortium

Cadmium telluride semiconductor detectors (CdTe) operating at room temperat ure are attractive for medical imaging because of their good energy resolut ion providing excellent spatial and contrast resolution. The compactness of the detection system allows the building of small light camera heads which can be used for bedside imaging. A mobile pixellated gamma camera based on 2304 CdTe (pixel size: 3 x 3 mm, field of view: 15 cm x 15 cm) has been de signed for cardiac imaging. A dedicated 16-channel integrated circuit has a lso been designed. The acquisition hardware is fully programmable (DSP card , personal computer-based system). Analytical calculations have shown that a commercial parrallel hole collimator will fit the efficiency/resolution r equirements for cardiac applications. Monte-Carlo simulations predict that the Moire effect can be reduced by a 15 degrees tilt of the collimator with respect to the detector grid. A 16 x 16 CdTe module has been built for the preliminary physical tests. The energy resolution was 6.16 +/- 0.6 keV (me an +/- standard deviation, n = 30). Uniformity was +/-10%, improving to +/- 1% when using a correction table. Test objects (emission data: letters 1.8 mm in width) and cold rods in scatter medium have been acquired. The CdTe i mages have been compared to those acquired with a conventionnal gamma camer a. (C) 1999 Elsevier Science B.V. All rights reserved.