UNLABELLED It is common, even with new SPECT/CT systems, that the transmission data are truncated. This paper develops a method that obtains exact attenuation correction with truncated transmission data. The emission object (e.g., the heart) is assumed to have a finite, convex support, whose emission projections are not truncated. The transmission measurements over the support are available, bu...

The problem of persistent bounded disturbance rejection for uncertain linear impulsive systems is considered in this paper. The systems under consideration is subject to polytopic uncertainties appearing in all matrices of the state-space model. By using positive invariant set and Lyapunov function methods, a sufficient condition for robust internal stability and L1-performance of the impulsive...

SUMMARY CT angiography (CTA) shows high sensitivity in detecting calcified plaques, but sometimes a bias in the exact quantification of stenosis degree occurs, mainly caused by the high linear attenuation coefficient of the calcified plaques. The purpose of this technical study was to evaluate the most appropriate CT window parameters for the assessment of calcified plaques stating which of the...

Ultrasonic attenuation may be measured accurately with clinical systems and array transducers by using reference phantom methods (RPM) to account for diffraction and other system dependencies on echo signals. Assumptions with the RPM are that the speeds of sound in the sample (c(sam)) and in the reference medium (c(ref)) are the same and that they match the speed assumed in the system beamforme...

Introduction: This study aimed to evaluate the efficacy of a synthesized bolus in the reduction of damage to body tissues and the protection of the organ at risk (OAR) in radiotherapy application. Several properties of the synthesized bolus, including density, transmission factor, and effective mass attenuation coefficient, were investigated. Material and ...

Abstract We performed tomographic investigation of the most heavily perturbed (thus highly radioactive) rod and its pristine/unirradiated replicate from target No. 12 Swiss neutron spallation source (SINQ). The dataset reveals 3D re-distribution lead filling inside irradiated Zircaloy tube. change in linear attenuation coefficient both tube (due to presence entrapped products) comparison with m...

High frequency ultrasound imaging (20 to 60 MHz) is increasingly being used in small animal imaging, molecular imaging and for the detection of structural changes during cell and tissue death. Ultrasonic tissue characterization techniques were used to measure the speed of sound, attenuation coefficient and integrated backscatter coefficient for (a) acute myeloid leukemia cells and corresponding...

In a previous work, we developed a consistent TAC (tissue attenuation coefficient) estimator using bubble echoes. Based on temporal averaging, we can improve the estimation precision of TAC for the tissue bounded between two vessels. In this paper, we extend it to use frequency diversity for saving interrogation time by transmit multiple narrowband signals in each pulse. At first, we analyze th...

With increasing demand for better yield in agricultural areas, soil physical property representative measurements are more and more essential. Nuclear techniques such as computerized tomography (CT) and gamma-ray attenuation (GAT) have been widely employed with this purpose. The soil mass attenuation coefficient (μ(s)) is an important parameter for CT and GAT analysis. When experimentally deter...