UNLABELLED BACKGROUND In single-photon emission computed tomography (SPECT), attenuation of photon flux in tissue affects quantitative accuracy of reconstructed images. Attenuation maps derived from X-ray computed tomography (CT) can be employed for attenuation correction. The attenuation coefficients as well as registration accuracy between SPECT and CT can be influenced by several factors....

Scatter correction is an important factor in single photon emission computed tomography (SPECT). Many scatter correction techniques, such as multiple-window subtraction and intrinsic modeling with iterative algorithms, have been under study for many years. Previously, we developed an efficient slice-to-slice blurring technique to model attenuation and system geometric response in a projectorhac...

Attenuation of photons in single-photon emission tomography (SPECT) makes three-dimensional reconstruction of unknown radioactivity distributions a mathematically intractable problem. Approaches to approximate SPECT reconstruction range from ignoring the effect of photon attenuation to incorporating assumed attenuation coefficients into an iterative reconstruction procedure. We have developed a...

PURPOSE Presence of photon attenuation severely challenges quantitative accuracy in single-photon emission computed tomography (SPECT) imaging. Subsequently, various attenuation correction methods have been developed to compensate for this degradation. The present study aims to implement an attenuation correction method and then to evaluate quantification accuracy of attenuation correction in s...

There has been a longstanding interest in fused images of anatomical information, such as that provided by computed tomography (CT) or magnetic resonance imaging (MRI) systems, with biological information obtainable by positron emission tomography (PET). The near-simultaneous data acquisition in a fixed combination of a PET and a CT scanner in a combined PET/CT imaging system minimizes spatial ...

Reconstruction of the tomographic images without attenuation correction can cause erroneously high count densities and reduced image contrast in low attenuation regions. In order to solve the problem of photon attenuation, one needs to know the attenuation coefficient for the individual patient being studied. Therefore, we made an attempt to correct the attenuation map in simultaneous transmiss...

Introduction:  The  advent  of  dual-modality  PET/CT  scanners  has  revolutionized  clinical  oncology  by  improving lesion localization and facilitating treatment planning for radiotherapy. In addition, the use of  CT images for CT-based attenuation correction (CTAC) decreases the overall scanning time and creates  a noise-free  attenuation  map  (6map).  CTAC  methods  include  scaling,  s...

We present Australia Telescope Compact Array observations towards 6 massive star formation regions which, from their strong 24GHz continuum emission but no compact 8GHz continuum emission, appeared good candidates for hyper-compact HII regions. However, the properties of the ionised gas derived from the 19 to 93GHz continuum emission and H70α + H57α radio recombination line data show the majori...

Objectives. The purpose of this study was to assess the efficacy of attenuation-corrected (AC) technetium-99m (Tc)tetrofosmin single-photon emission computed tomography (SPECT) in detecting viable myocardium compared to Ffluorodeoxyglucose (FDG) positron emission tomography (PET). Background. The role of Tc-labeled perfusion tracers in the assessment of myocardial viability remains controversia...