statement of the problem in order to replace lost tooth of patients, we use dental implants which are common. therefore, accurate measuring of bone height and width before placing implants is necessary. the aim of this study is evaluating the accuracy of linear and spiral tomography in careful determination of implant site sizes in comparison with gold standard (cbct). material and methods this...

objectives: bone quality and quantity assessment is one of the most important steps in implant treatment planning. different methods such as computed tomography (ct) and recently suggested cone beam computed tomography (cbct) with lower radiation dose and less time and cost are used for bone density assessment. this in vitro study aimed to compare the tissue density values in hounsfield units (...

Introduction: According to the literature, optical coherence tomography (OCT) can be used measure radiation absorbed dose. This study was carried out to design a computed tomography system for the calculation of absorbed dose and optimization of dose delivery in radiotherapy using gel dosimeters. Material and Methods: An advanced charge-coupled device based OCT system was developed in laborator...

OBJECTIVE This work aims to explore the effects of adaptive statistical iterative reconstruction (ASiR) and model-based iterative reconstruction (MBIR) algorithms in reducing computed tomography (CT) radiation dosages in abdominal imaging. METHODS CT scans on a standard male phantom were performed at different tube currents. Images at the different tube currents were reconstructed with the fi...

The increased use of computed tomography (CT) and its high radiation dose have led to great concerns about its potential for radiation induced cancer risks. Breast is a radiosensitive tissue based on tissue weighting factors assigned by the International Commission on Radiological Protection (ICRP). Moreover, the dose is maximal on the surface of the patient. Therefore, strategies should be tak...

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...

Introduction: The rapid use of computed tomography (CT) scan is of great concern, due to increase in patients’ dose. Optimization of CT protocol is a vital issue in dose reduction. This study aimed to optimize radiation dose in cranial CT and assess modifications in image quality under radiation dose reduction. Material and Methods: A poly(me...

Objective: To determine the effective dose in abdominal computed tomography imaging and to study the influence of patients’ characteristics on the received dose. Materials and Methods: Dose values measurements were performed with an ionization chamber on phantoms to check the agreement between dose values and those presented by the computed tomography apparatus, besides their compliance with th...