background: pregnant women are sometimes exposed to ionizing radiation in radiology examinations for various reasons. in such cases, the radiation dose to the conceptus and subsequent risks should be estimated. objective: the purpose of this study was the calculation and presentation of fetal dose and subsequent risks resulted from different x-ray examinations. materials and methods: an analyti...

background: the radiation doses resulting from diagnostic x-ray examinations are routinely measured in terms of entrance surface dose (esd) and effective dose (ed). in this study, for the purpose of radiation protection, the radiation doses received from digital chest x-ray examination were evaluated in terms of esd and ed. material and methods: the ed was calculated by using the mcnp monte car...

background: exposure conditions in ct examinations are quite different from conventional xray. in ct examination higher dose is given to patient in comparison with the dose in other diagnostic examinations. in order to calculate organ effective dose in chest ct, monte carlo simulation has been used in this study. materials and methods: the impact survey data were used to determine the parameter...

ct.scan examinations cause high patient absorbed dose from x-ray ionizing radiation. therefore it is necessary to obtain superficial dose profile in z-line. in this research 11 thermoluminecent dosimeter (tld), after calibration were located on z line perpendicular to slice thickness. ct.scan machines did x-ray exposures. the resultant dose profiles showed gussian shape apperience, which has se...

background: increasing the x-ray focus to film distance (ffd) has been advocated as an effective method to reduce the patients’ radiation dose. the aim of this study was to investigate the efficacy of this technique in patients' dose and image quality in pediatric chest x-ray.material and methods: sixty pediatric patients were x-ray imaged at ffds of 100 and 130 cm. dose measurements were ...

Background: Medical x-rays are the largest man-made source of public exposure to ionizing radiation. It is important to avoid conditions where the amount of radiation used is more than that needed for the procedure. Materials and Methods: The Entrance Skin Exposure (ESE) measurement was conducted for quality control of x-ray machines and survey of operator’s experimental techniques. The ESEs we...

objective: due to recent advances in nanotechnology it is now possible to accumulate high atomic-number nanomaterial such as gold nanoparticles (gnps) in cancerous cells and take advantage of their absorbed dose enhancement property as radiosensitizing agents. this study aimed to investigate the absorbed dose enhancement factor due to the presence of pegylated gnps under the irradiation of an m...

Background: Increasing the x-ray focus to film distance (FFD) has been advocated as an effective method to reduce the patients’ radiation dose. The aim of this study was to investigate the efficacy of this technique in patients' dose and image quality in pediatric chest x-ray.Material and methods: Sixty pediatric patients were x-ray imaged at FFDs of 100 and 130 cm. Dose measurements were perfo...

background: monte carlo and experimental relative dose determination in a water phantom, due to a high dose rate (hdr) 192ir source is presented for real energy spectrum and monochromatic at 356 kev. materials and methods: the dose distribution has been calculated around the 192ir located in the center of 30 cm ×30 cm ×30 cm water phantom using mcnp4c code by monte carlo method. relative dose v...