introduction: one of the major causes of image non-uniformity in mri is due to the existence of  non-homogeneity in rf receive and transmit. this can be the most effective source of error in  quantitative  studies  in  mri  imaging.  part  of  this  non-homogeneity  demonstrates  the  characteristics of rf coil and part of it is due to the interaction of rf field with the material being  imaged...

Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to det...

introduction: non-uniformity test is essentially the only required daily qc procedure in nuclear medicine practice. noise creates statistical variation or random error in a flood image. non-uniformity on the other hand does not have statistical nature and may be regarded as systemic error. the present methods of non-uniformity calculation do not distinguish between these two types of error. the...

Introduction: Non-uniformity test is essentially the only required daily QC procedure in nuclear medicine practice. Noise creates statistical variation or random error in a flood image. Non-uniformity on the other hand does not have statistical nature and may be regarded as systemic error. The present methods of non-uniformity calculation do not distinguish between these two types of erro...

Background: Cone-beam computed tomography (CBCT) scanners for image-guided radiotherapy are in clinical use today, but there has been no consensus on uniform acceptance to verify the CBCT image quality yet. The present work proposed new methods to fully evaluate the performance of CBCT in its three-dimensional (3D) reconstruction space. Materials and Methods: Compared to the traditional methods...

introduction: the different factors that affect the camera uniformity of single photon emission computed tomography (spect) technique have been analyzed including peak shift (%) and window width of energy. the effect of peak shift and window width on spect image uniformity has been investigated using a point source to perform intrinsic flood images. methods:the relation between calculated integ...

Introduction: The different factors that affect the camera uniformity of Single Photon Emission Computed Tomography (SPECT) technique have been analyzed including peak shift (%) and window width of energy. The effect of peak shift and window width on SPECT image uniformity has been investigated using a point source to perform intrinsic flood images. Methods:</stro...

In this paper we present a new feature of texture images which can scale the uniformity degree of image texture directions. The feature value is obtained by examining the statistic characteristic of the gradient information of the image pixels. Simulation results illustrate that this feature can exactly coincide with the uniformity degree of image texture directions according to the perception ...