Brain magnetic resonance imaging without contrast significantly increased serum levels of IL-6, but not IL-10, IL-17A and TGF-β.

: Magnetic Resonance Imaging (MRI) is a non-invasive imaging modality. However, the effects of MRI on the immune system in the in vivo conditions are yet to be clarified. In this study we explored the effects of routine brain MRI on the protein and mRNA peripheral blood levels of interleukin-6 (IL-6), IL-10, IL-17A and transforming growth factor-beta (TGF-β).

PATIENT DOSE SURVEY BASED ON SIZE-SPECIFIC DOSE ESTIMATE AND ACCEPTABLE QUALITY DOSE IN CHEST AND ABDOMEN/PELVIS CT EXAMINATIONS.

The practical aspects of two recently developed patient dose optimization methods in computed tomography (CT) examinations, size-specific dose estimate (SSDE) and acceptable quality dose (AQD), were verified for the chest and abdomen/pelvis examinations. A dose survey was performed in a CT institute by considering patients lateral diameter, weight and body mass index (BMI). The AQD tables for weight and BMI groups and SSDE threshold curves were obtained.

Statistical analysis for obtaining optimum number of CT scanners in patient dose surveys for determining national diagnostic reference levels.

Objectives: To statistically determine an 'optimum number of CT scanners' for obtaining 'diagnostic reference levels' (DRLs) in CT examinations as close as possible to 'ideal DRLs' when all available CT scanners are considered.

Methods: First, six 'ideal DRLs' (CTDI and DLP) were determined for head, chest and abdomen/pelvis examinations by using patient-dose survey data of 100 CT scanners of different models in Tehran. Then, a 'random sampling method' was applied to different percent fractions of patient dose data of 100 CT scanners.

A New Dual-purpose Quality Control Dosimetry Protocol for Diagnostic Reference-level Determination in Computed Tomography.

A diagnostic reference level is an advisory dose level set by a regulatory authority in a country as an efficient criterion for protection of patients from unwanted medical exposure. In computed tomography, the direct dose measurement and data collection methods are commonly applied for determination of diagnostic reference levels. Recently, a new quality-control-based dose survey method was proposed by the authors to simplify the diagnostic reference-level determination using a retrospective quality control database usually available at a regulatory authority in a country.

Determination of Examination-Specific Diagnostic Reference Level in Computed Tomography by A New Quality Control-Based Dose Survey Method.

A new "quality-control-based (QC-based) dose survey method" has been developed for determination of diagnostic reference levels (DRL) in Computed Tomography (CT) examinations. The "QC-based dose survey method" is based on the use of retrospective data in the QC documents and reports, which are typically available from the National Regulatory Authority database. The method was applied to 70 CT scanners in Tehran, Iran, by using the available QC reports from the database.

DETERMINATION OF NATIONAL DIAGNOSTIC REFERENCE LEVELS IN COMPUTED TOMOGRAPHY EXAMINATIONS OF IRAN BY A NEW QUALITY CONTROL-BASED DOSE SURVEY METHOD.

National diagnostic reference levels (NDRLs) of Iran were determined for the four most common CT examinations including head, sinus, chest and abdomen/pelvis. A new 'quality control (QC)-based dose survey method', as developed by us, was applied to 157 CT scanners in Iran (2014-15) with different slice classes, models and geographic spread across the country. The NDRLs for head, sinus, chest and abdomen/pelvis examinations are 58, 29, 12 and 14 mGy for CTDIVol and 750, 300, 300 and 650 mGy.

A "quality-control-based correction method" for displayed dose indices on CT scanner consoles in patient dose surveys.

Purpose: A new quality-control-based (QC-based) method is introduced to obtain correction factors to be applied to displayed patient dose indices (CTDI and DLP) on CT scanner consoles to verify improvement of dose surveys for diagnostic reference levels (DRLs) determination.

Method: An available data-base of QC documents and reports of 57 CT scanners in Tehran, Iran was used to estimate CTDI, DLP and relevant correction factors for three CT examination types including head, chest and abdomen/pelvis. The correction factor is the ratio of QC-based estimated dose to displayed dose.

GANTRY ANGULATION EFFECTS ON CT DOSE ALONG THE Z-AXIS DIRECTION IN HEAD EXAMINATIONS.

The purpose of this study was to evaluate the effects of the gantry angulation on dose profiles along the z-axis, the CTDIW value and the CTDIW efficiency in the head examinations. A Monte Carlo simulation model of a GE LightSpeed 16-slice CT scanner was developed by a GATE toolkit. The CTDI100 in air at the isocenter and in a head dosimetry phantom were measured using a pencil ion chamber.