PURPOSE Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT) images from an original higher dose scan. MATERIALS AND METHODS Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV) of a swine were acquired (approved by the regional governmental commission for animal protection). Simulations of CT acquisition with a lower dose ...

We investigated the sensitivity of the gamma index to two factors: the spatial resolution and the noise level in the measured dose distribution. We also examined how the choice of reference distribution and analysis software affect the sensitivity of gamma analysis to these two factors for quality assurance (QA) of intensity-modulated radiation therapy (IMRT) treatment plans. For ten clinical I...

The γ-index test has been commonly adopted to quantify the degree of agreement between a reference dose distribution and an evaluation dose distribution. Monte Carlo (MC) simulation has been widely used for the radiotherapy dose calculation for both clinical and research purposes. The goal of this work is to investigate both theoretically and experimentally the impact of the MC statistical fluc...

OBJECTIVE To assess effects of off-centering, automatic exposure control, and padding on attenuation values, noise, and radiation dose when using in-plane bismuth-based shields for CT scanning. MATERIALS AND METHODS A 30 cm anthropomorphic chest phantom was scanned on a 64-multidetector CT, with the center of the phantom aligned to the gantry isocenter. Scanning was repeated after placing a b...

The main purpose of this work is to study the ability of denoising algorithms to reduce the radiation dose in Digital Breast Tomosynthesis (DBT) examinations. Clinical use of DBT is normally performed in “combo-mode”, in which, in addition to DBT projections, a 2D mammogram is taken with the standard radiation dose. As a result, patients have been exposed to radiation doses higher than used in ...

AIM To compare radiation dose and image quality of low-dose computed tomography (CT) protocol combined with hybrid-iterative reconstruction algorithm with standard-dose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standard-dose and low-dose whole-body CT scans were enrolled. Low-d...

BACKGROUND AND PURPOSE The purpose of this work was to evaluate the possible use of low-dose multidetector CT (MDCT) in cervical clearance of patients with blunt trauma. MATERIALS AND METHODS A total of 191 patients underwent cervical spine MDCT with 6- and 16-MDCT: standard-dose (n = 51) and low-dose MDCT with tube current modulation at high (n = 70) and low (n = 70) tube voltage (kilovolts)...

OBJECTIVE The objective of our study was to evaluate the effect of organ-based tube current modulation and bismuth shielding on image quality and breast radiation dose in women undergoing low-dose chest CT. SUBJECTS AND METHODS From March 2011 through July 2011, 80 women prospectively underwent low-dose chest CT to screen for lung cancer. The patients were randomly assigned to a control group...

BACKGROUND AND PURPOSE CT performed with Veo model-based iterative reconstruction has shown the potential for radiation-dose reduction. This study sought to determine whether Veo could reduce noise and improve the image quality of low-dose sinus CT. MATERIALS AND METHODS Twenty patients consented to participate and underwent low- and standard-dose sinus CT on the same day. Standard-dose CT wa...

One of the most important challenging factors in medical images is nominated as noise. Image denoising refers to the improvement of a digital medical image that has been infected by Additive White Gaussian Noise (AWGN). The digital medical image or video can be affected by different types of noises. They are impulse noise, Poisson noise and AWGN. Computed tomography (CT) images are subjects to ...