introduction: variable resolution x-ray (vrx) ct is a new type of ct that can image objects at various spatial resolutions. in a vrx ct scanner, the spatial resolution increases at the cost of reduction in the field of view (fov). an important factor that limits the spatial resolution of the vrx ct is the effect of focal spot size. also, the optimum magnification is different at each incident a...

background: a variable resolution x-ray (vrx) ct scanner provides a great increase in the spatial resolution. in vrx ct scanners, the spatial resolution of the system and its field of view (fov) can be changed according to the object size. one of the main factors that limit the spatial resolution of vrx ct scanner is the effect of the x-ray focal spot. materials and methods: a theoretical study...

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. Advances in PET technology have lead to widespread applications in diagnostic imaging and oncologic staging of dise...

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. Advances in PET technology have lead to widespread applications in diagnostic imaging and oncologic staging of dise...

Generally, computerised tomography (CT) is an X-ray based non-destructive testing method that was developed for medical purposes in the seventies and introduced for industrial applications during the eighties. CT produces maps of the X-ray linear attenuation coefficient of an object’s interior; presented either as cross section images (two-dimensional CT) or as volume information (three-dimensi...

Conventional x-ray computed tomography (CT) produces a single volumetric image that represents the spatially variant linear x-ray attenuation coefficient of an object. However, in many situations, differences in the x-ray attenuation properties of soft tissues are very small and difficult to measure in conventional x-ray imaging. In this work, we investigate an analyzer-based imaging method, ca...

OBJECTIVE Computed tomography (CT), rather than conventional 2-dimensional radiography, was used to scan and measure pelvic parameters. The results were compared with measurements using X-ray. METHODS Pelvic parameters were measured using both CT and X-ray in 254 patients who underwent both abdomino-pelvic CT and X-ray at the pelvic site. We assessed the similarity of the pelvic parameters be...

Radiologic Procedure Rating Comments RRL* CT abdomen and pelvis without and with IV contrast 2 ☢ ☢ ☢ ☢ X-ray abdomen 2 ☢ ☢ CT abdomen and pelvis without IV contrast 2 ☢ ☢ ☢ ☢ CT abdomen and pelvis with IV contrast 2 ☢ ☢ ☢ ☢ X-ray IV contrast enema 2 ☢ ☢ ☢ X-ray cystography 2 ☢ ☢ ☢ MRI pelvis without and with IV contrast 2 MRI may be indicated if urethral diverticulum is suspected. O MRI pelvis ...

Background: In CT systems, the machine utilizes a bowtie filter to shape the X-ray beam and remove lower energy photons. The shape of this bowtie filter is complicated and its geometry is often not available in detail. These renders the CT dose index (CTDI) to have different values in measurement versus Monte Carlo simulation studies and other analytical calculations especially in dosimetry of ...

background and aims. cone-beam computed tomography (cbct) is an imaging system which has many advantages over computed tomography (ct). in ct scan, hounsfield unit (hu) is proportional to the degree of x-ray attenuation by the tissue. in cbct, the degree of x-ray attenuation is shown by gray scale (voxel value). the aim of the present study was to investigate the relationship between gray scale...