introduction: filtering can greatly affect the quality of clinical images. determining the best filter and the proper degree of smoothing can help to ensure the most accurate diagnosis. methods: forty five patient’s data aquired during brain phantom spect studies were reconstructed using filtered back-projection technique. the ramp, shepp-logan, cosine, hamming, hanning, butterworth, metz and w...

introduction: the limited resolution of the imaging system causes partial volume effects (pves). these results in spreading of image counts to the neighboring pixels. this phenomenon is called spill-out effect. this study aimed at quantifying pves using imagej. methods:technetium-99m solution of concentration of 74 kbq/ml was filled into spheres a, b and c of diameters: 26 mm, 20 mm and 16 mm r...

introduction: image quality and accuracy of in vivo activity quantification in spect are affected by collimator penetration and scatter components, especially in high energy imaging. these phenomena highly depend on the collimator characteristic and photon energy. the presence of penetrated and scattered photons from collimator in spect images degrades spatial resolution, contrast and image qua...

to date, a number of numerical methods, including the popular finite-difference time domain (fdtd) technique, have been proposed to simulate ground-penetrating radar (gpr) responses. despite having a number of advantages, the finite-difference method also has pitfalls such as being very time consuming in simulating the most common case of media with high dielectric permittivity, causing the for...

introduction in computed tomography (ct) technology, an optimal radiation dose can be achieved via changing radiation parameters such as ma, pitch factor, rotation time and tube voltage (kvp) for diagnostic images. materials and methods in this study, the brain, abdomen, and thorax scaning was performed using toshiba 16-slice scannerand standard aapm and ctdi phantoms. aapm phantom was used for...

objectives: this study aimed to assess the effect of voxel size and object location in the field of view (fov) on diagnostic accuracy of cone beam computed tomography (cbct) for detection of simulated bone defects. materials and methods: in this in vitro study, bone defects were drilled in four sections of a dry human mandible. bone blocks were fixed on a platform parallel to the horizontal pla...