UNLABELLED Sequential transmission scanning (TS)/SPECT is impractical for neurologically impaired patients who are unable to keep their heads motionless for the extended duration of the combined scans. To provide an alternative to TS, we have developed a method of inferring-attenuation distributions (IADs), from SPECT data, using a head atlas and a registration program. The validity of replacin...

This figure "pict2.png" is available in "png"" format from: A simple model of X-Ray standing waves (XSW) formation in the slit of a planar waveguide of X-Ray radiation beam for the angle area restricted by the critical total reflection angle is developed. It is shown that the model is true for a case of the Bragg reflection. The conditions required for XSW to appear in the space between two pol...

PURPOSE A phantom study was conducted to evaluate the feasibility of body contour definition with Compton scatter photons from external sources of technetium-99m pertechnetate (Tc-99m) to create a fusion image of CT and SPECT images. METHODS External sources of 1 mCi (37 MBq) Tc-99m were placed on each collimator, and body-contour SPECT images were obtained with an energy window of 100 keV +/...

UNLABELLED Attenuation of photons degrades both the accuracy and the precision of SPECT images; attenuation correction algorithms correct the bias but cannot improve precision. Increased noise due to photon attenuation is most pronounced in regions deep in solid body sections, such as the brain and abdomen. We have quantified the degradation in performance in several estimation tasks that can b...

We assessed improvements in performance in detection and estimation tasks due to a novel brain single photon computed tomography collimator. Data were acquired on the CeraSPECT scanner using both new and standard collimators. The new variable focusing collimator SensOgrade samples the projections unequally, with central regions more heavily represented, to compensate for attenuation of counts f...

Previously, several studies have reported that a decreasing image quality in heavier patients in myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) can be compensated by using a body-weight-dependent tracer activity or scan time, as illustrated in Figure 1. Although we derived and validated a activity-scan-time formula for a conventional SPECT scanner, t...

Previously, several studies have reported that a decreasing image quality in heavier patients in myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) can be compensated by using a body-weight-dependent tracer activity or scan time, as illustrated in Figure 1. Although we derived and validated a activity-scan-time formula for a conventional SPECT scanner, t...

SWAP-70-like adapter of T cells (SLAT) is a novel guanine nucleotide exchange factor for Rho GTPases that is upregulated in Th2 cells, but whose physiological function is unclear. We show that SLAT(-/-) mice displayed a developmental defect at one of the earliest stages of thymocyte differentiation, the double-negative 1 (DN1) stage, leading to decreased peripheral T cell numbers. SLAT(-/-) per...

BACKGROUND Imaging techniques enable in vivo sequential assessment of the morphology and function of animal organs in experimental models. We developed a device for high-resolution single photon emission computed tomography (SPECT) imaging based on an adapted pinhole collimator. OBJECTIVE To determine the accuracy of this system for quantification of myocardial infarct area in rats. METHODS...