Pediatric 99mTc-MDP Bone SPECT with Ordered Subset Expectation Maximization Iterative Reconstruction with Isotropic 3D Resolution Recovery

Purpose: To perform a preliminary evaluation of the image quality of pediatric technetium 99m (Tc-99m) methylene diphosphonate (MDP) bone single photon emission computed tomography (SPECT) by using iterative reconstruction-ordered subset expectation maximization with three-dimensional resolution recovery (OSEM-3D)-and to assess whether any improvements with use of this technique could lead to a reduction in patient dose or a shortening in imaging time. Materials and Methods: Institutional advisory board approval was obtained for this investigation. Fifty Tc-99m-MDP SPECT studies of the spine were evaluated (36 female and 14 male patients; mean age, 15.5 years). Each study was acquired by using a dual-detector camera, with each detector rotating 360 degrees. By using filtered back projection (FBP) and OSEM-3D, images were reconstructed from data generated by both detectors. Likewise, OSEM-3D was used to reconstruct data from a single detector simulating half the administered radiopharmaceutical activity. Two nuclear medicine physicians, blinded to the patient data, reviewed the images for image quality in four different categories by using a four-point scale: artifacts (category 1), lesions (category 2), noise (category 3), and image sharpness (category 4). Results: Compared with FBP, images reconstructed by using OSEM-3D with one or two detectors showed significant improvement in image quality with regard to lesion detection, noise level, and image sharpness (P < .02, .01, and .001, respectively). With OSEM-3D, no significant differences were observed when either one or two detectors were used. Conclusion: Improved image quality of skeletal SPECT with either a 50% reduction in radiation dose or a 50% reduction in acquisition time or combination of the two can be achieved by using OSEM-3D. (C)RSNA, 2010