Half-dose versus half-time myocardial perfusion SPECT (MPI) with wide beam reconstruction

598 Objectives Wide Beam Reconstruction (WBR) (UltraSPECT, Ltd) uses resolution recovery and noise modeling to cope with decreased SPECT count statistics. Because WBR processing reconstructs half the usual SPECT count statistics, we postulate that image quality equivalent to a full-time acquisition can be achieved in either half the time or with half the radiopharmaceutical dose. Methods In 156 consecutive patients (pts) rest and 8-frame gated post-stress MPI was performed following 9-12 mCi and 32-40 mCi Tc-99m sestamibi injections respectively with full-time (rest = 14 min; stress = 12.3 min) acquisitions processed with OSEM and also separate "half-time" (HT) acquisitions processed with WBR. A subsequent group of 160 consecutive pts matched in gender, weight, and chest circumference received “half-dose” (HD) rest and stress injections (5.8±0.6 and 17.5±2.5 mCi) with full-time SPECT acquisitions. Image quality (1 = poor to 5 = excellent) was judged by myocardial count density and uniformity, endocardial edge definition, perfusion defect delineation, right ventricular visualization, and background noise. Results Perfusion defects were present in 82/156 HT and 72/160 HD pts. Mean image quality for rest, stress, and post-stress gated MPI were: "" HT and HD WBR image quality were both superior to standard full-time OSEM (p’s Conclusions Both HT and HD WBR provide MPI quality superior to full-time OSEM. HD quality may be superior to HT due to a lesser percentage of total SPECT acquisition time required for camera motion between stops. A HD WBR protocol halves patient radiation exposure. According to published estimates, the mean effective dose is ~6 mSv with the HD protocol vs. ~11 mSv with either a standard full-dose protocol or a HT WBR protocol. Research Support UltraSPECT Ltd., Haifa, Israe