Automatic tube current modulation (ATCM) on CT scanners can yield significant reductions in patient doses. Modulation is based x-ray beam attenuation body tissues obtained from scan projection radiographs (SPRs) and aims to maintain the same level of image quality throughout a scan. Noise important judging quality, but larger patients exhibit higher contrast resulting presence fat. scanner manufacturers use different metrics assess quality. Some employ simple measure noise, while others...

Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles ATCM operation different in scanners from manufacturers. Toshiba and GE base on a target noise setting, while Philips Siemens use reference image mAs concepts respectively. Knowledge relationships between patient size, dose important optimisation. In this study, doses were surveyed 14 four scanner cross sectional area, images analysed using in-house software. results showed that levels...

Modern CT scanners modulate tube current during scans according to patient size, shape and attenuation. However, the ATCM (automatic modulation) systems for different manufacturers work on principles. Although are used majority of patients examinations, there is no standard phantom routine quality control scanner operation. The ideal testing these should be capable evaluating how image as well dose vary changes in size shape. For this study, a conical designed by ImPACT has been compared...

Gafchromic film has been used for measurement of computed tomography (CT) dose distributions within phantoms. The was calibrated in the beam from a superficial therapy unit and accuracy confirmed by comparison with measurements 20 mm long ionisation chamber. results have to investigate approaches CT dosimetry. Dose profiles were recorded standard head body phantoms scatter tail data fitted exponential functions extrapolated predict levels longer simulate both index (CTDI) chambers differing...

Variation in the user selected CT scanning parameters under automatic tube current modulation (ATCM) between hospitals has a substantial influence on radiation doses and image quality for patients. The aim of this study was to investigate effect changing reconstruction filter scan parameter settings current, dose various scanners operating ATCM. varied were pitch factor, rotation time, collimator configuration, kVp, thickness convolution (FC) used reconstruction. Toshiba scanner varies...

The use of computed tomography (CT) scanning has been growing steadily. Therefore, CT dose measurement is becoming increasingly important for patient protection and optimization. A phantom an tool measurement. This paper focuses on the evaluation a dosimetry made from nylon, instead standard polymethyl methacrylate (PMMA), which not readily available or too expensive in some countries. Comparison between phantoms two materials terms measurements indices (CTDI). These were measured four...

There has been an expansion in the use of x-ray imaging during last 20 years. Effective arrangements for justification exposures as well optimisation protection are crucial. The amount effort put into latter, way which it is organised and groups carrying this out vary across globe. A simple survey organisational relating to performance testing equipment, management patient dose other aspects implementing undertaken. total 137 completed forms were received from medical physicists 48...

Computed tomography (CT) performance assessments relating to patient dose the body are made conventionally in 320 mm diameter cylindrical acrylic phantoms. The cross section of human trunk is closer an ellipse and automatic tube current modulation (ATCM) systems adjust exposure level with orientation x-y plane, changing distribution within body. This study has investigated differences distributions a standard phantom elliptical dosimetry for Toshiba, General Electric Philips CT scanners,...

Computed tomography (CT) automatic tube current modulation (ATCM) systems and iterative reconstruction (IR) play an important role in CT radiation dose optimization. How the two can best be used together is one of challenges faced by radiology professionals.To determine optimum settings ATCM noise index (NI) with adaptive statistic (ASIR) for a general electric (GE) scanner that aims to achieve similar image quality standard protocol hospital (Smart mA technique NI 11.57 30% ASIR...

Automatic tube current modulation (ATCM) systems to aid in optimizing dose and image noise have become standard on computed tomography (CT) scanners over the last decade. ATCM of main vendors modulate slightly different ways, with some using a control parameter related (e.g. Toshiba, GE) while others use quality reference mAs Siemens). The translation clinical protocols including operation between CT from manufacturers order obtain similar levels optimized exposure variables has an important...

The effects of tube potential selection with a computed tomography (CT) automatic current modulation (ATCM) system on radiation dose and image quality have been investigated Canon CT scanner. use different values voltage for imaging, the appropriate settings ATCM system, were evaluated. custom-made phantom consisted three sections sizes inserts various materials. It was scanned using potentials 80-140 kV settings. CTDIvoland in terms noise, contrast, contrast-to-noise ratio (CNR) air,...

Automatic tube current modulation (ATCM) is now available on all computed tomography (CT) scanners, but there no standard phantom for testing its operation. For this study, a comprising five elliptical sections of varying diameters in the shape pagoda has been made to represent range sizes patients Thailand and Far East. ATCM performance can be evaluated terms how image noise vary with changes sections. Additional rods different materials similar properties human tissues have inserted allow...

Computed tomography (CT) scanners are equipped with automatic tube current modulation (ATCM) systems that adjust the to compensate for variations in patient attenuation. CT dosimetry variables not defined ATCM situations and, thus, only averaged values displayed and analysed. The effective dose (E), which is derived from a weighted sum of organ equivalent doses, will be modified by ATCM. Values E chest-abdomen-pelvis scans have been calculated using ImPACT spreadsheet patients on five...

Contrast-induced nephropathy (CIN) is an adverse reaction associated with the use of intravenous contrast media (CM).To investigate impact low tube voltage settings on single-energy computed tomography (SECT) and rapid kV switching dual-energy CT (DECT) reduced concentrations iodinated CM.A phantom containing four different CM (original concentration CM, 20%, 40%, 60% reductions) was scanned using SECT mode varying voltages (70, 80, 100, 120 kVp) DECT through reconstructing monoenergetic...

The effective dose resulting from computed tomography (CT) scans provides an assessment of the risk associated with stochastic effects but does not account for patient's size. Advances in Monte Carlo simulations offer potential to obtain organ data phantoms varying stature, enabling derivation a size-specific doses (SEDs) representing individual patients. This study aimed compute k-conversion factors SED routine CT examinations adult and pediatric patients different sizes. Radiation...

The objectives of this study were to assess the feasibility utilizing computational calculations and simulation National Cancer Institute computed tomography (NCICT) dosimetry system obtain size-specific dose estimate (SSDE) effective values resulting from most common CT examinations in Thai pediatric patients evaluate age- k conversion factor. For calculation methods, SSDEs calculated using American Association Physicists Medicine Report No. 220 293 methodologies. results revealed that...

Values for the CTDIvol, which is displayed on scanner consoles, give doses relative to a phantom much larger than most Thai patients, and CTDIvol does not take account of differences in patient size, affect organ doses.The purpose this study was evaluate relationships size specific dose estimate (SSDE) volume weighted computed tomography (CT) index (CTDIvol) with CT scanners operating under automatic tube current modulation (ATCM).Retrospective data from 244 patients who had undergone...

The volumetric computed tomography (CT) dose index (CTDIvol) is the measure of output displayed on CT consoles relating to within a standard phantom. This gives false impression doses levels tissues smaller patients in Southeast Asia. A size-specific estimate (SSDE) can be calculated from CTDIvolto provide an assessment at specific positions scan using conversion factors. SSDE derived water equivalent diameter (Dw) patient, but calculation ofDwrequires sophisticated computer software. study...