introduction computed tomography scans are a very important tool for diagnosis and assessment of response to treatment in the practice of medicine. ionizing radiation in medical imaging is undoubtedly one of the most powerful diagnostic tools in medicine. yet, as with all medical interventions, there are potential risks in addition to the clear potential benefits. materials and methods two refe...

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...

nasopharyngeal angiofibroma is a relatively uncommon vascular tumor affecting adolescent males and it characteristically originates in the posterior lateral wall of the nasopharynx. primary extra-nasopharyngeal angiofibroma is very rare. here, i present a case of angiofibroma of the parapharyngeal space in a 53-year-old woman with ct and sonographic findings.

the presence of anatomic variations of paranasal sinuses must be noted in order to attain a full understanding and accurate diagnosis of chronic sinusitis. the frequency of anatomic variations in chronic sinusitis is different in various studies. the purpose of this study is to assess the frequency of anatomic variations in chronic sinusitis patients admitted to otolaryngology ward of shahid sa...

introduction in ct imaging, metallic implants inside the tissues cause metal artifact that reduce the quality of image for diagnosis. in order to reduce the effect of this artifact, a new method with more appropriate results has been presented in this research work. materials and methods the presented method comprised of following steps: a) image enhancement and metal areas extraction, b) sinog...

ct image quality has been affected by many factors such as kvp, ma, exposure time, alogorithm and section thickness. gantry tilt has the main role in visualization of the temporal bone anatomic structures. in this study, we tried to optimize these factors to determine the best gantry tilt. this study was performed on the human skull phantom and then extended to 15 patients. the phantom was made...