نتایج جستجو برای: ctdi measurement
تعداد نتایج: 441251 فیلتر نتایج به سال:
ین پایان نامه با هدف سنتز و شناسایی چهار نوع از نانو ذرات آغاز می شود. نانو ذرات آلوم اکسان از واکنش بوهمیت و کربوکسیلیک اسید مربوطه حاصل شدند. هدف از سنتز این نوع نانو ذرات ساخت غشاهای عامل دار شده با خاصیت آب دوستی و انتخاب پذیری جهت جداسازی روغن از مخلوط های آب و روغن، می باشد. tg-dta، ftir، sem، tem، uv/vis spectrophotometer، digital camera،contact angle measurement goniometer، ultrasonic b...
Introduction: In 2000, the UNSCEAR reported that CT constitutes 5% of all the medical x-ray examinations and it contributes 34% of the resultant collective dose worldwide. Children are more sensitive to the ionizing radiations than adults. So, routine quality control tests are expected to be carried out periodically on the CT scanners. The aim of this research was to estimate the effective ...
Analysis and Evaluation of Computed Tomography Dose Index (CTDI) of Pediatric Brain by Hospital Size
We assess dose and image quality of a state-of-the-art angiographic C-arm system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) for three-dimensional neuro-imaging at various dose levels and tube voltages and an associated measurement method. Unlike conventional CT, the beam length covers the entire phantom, hence, the concept of computed tomography dose index (CTDI) is not th...
New methods of dosimetry in computed tomography (CT) X-ray fields require the use of high-resolution detectors instead of pencil-type ionization chambers typically used for CT dose index (CTDI) measurements. This paper presents a study on the suitability of a wide range of ionization chambers, diodes, and a two-dimensional detector array, used primarily in radiation therapy, for CT and cone-bea...
Radiation doses to Patient during CT scanner and the radiological risk are significant. Patient dose survey has been conducted toinvestigate the Iraq patient radiation dosesreceived in CT scanners in order to established reference dose levels. These doses are Entrance Surface Dose (ESD),computed tomography dose index(CTDI)), and dose length product (DLP). Two CT scanner were investigated in thi...
This study is designed to accurately simulate a helical CT-scanner for the purpose of estimating radiation dose and to perform validation experiments involving several dose profile and ionization chamber measurements. To accomplish this we have modified a general purpose Monte Carlo transport code (MCNP4B) as the framework for simulating the x-ray source and its movement, photon transport and r...
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