scholarly journals The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography

2015 ◽  
Vol 45 (12) ◽  
pp. 1814-1822 ◽  
Author(s):  
Joana Santos ◽  
Shane Foley ◽  
Graciano Paulo ◽  
Mark F. McEntee ◽  
Louise Rainford
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Dose Modulation ◽  
The Impact ◽  
Head Computed Tomography

scholarly journals Utilization of sinogram affirmed iterative reconstruction on 128 multi slice computed tomography scan to reduce radiation dose and improve image quality on thorax multi slice computed tomography scan: chest phantom study

2019 ◽  
Vol 6 (10) ◽  
pp. 4533
Author(s):  
Halinda Fatmayanti ◽  
Kusworo Adi ◽  
Yeti Kartikasari
Keyword(s):  
Computed Tomography ◽  
Experimental Study ◽  
Image Quality ◽  
Radiation Dose ◽  
Dose Assessment ◽  
Computed Tomography Scan ◽  
Tube Voltage ◽  
The Impact ◽  
Tomography Scan

Background: Thorax MSCT examination is a diagnostic imaging that is capable of displaying both normal and pathological lung and respiratory organs. MSCT examination also has a better level of sensitivity and specificity compared to other modalities, but the radiation exposure given is very high, so the radiation dose given to patients is high. The reduction in radiation dose is very important because of the direct exposure to sensitive tissue. One method of reducing radiation dose is by reducing the tube voltage. However, the decrease in tube voltage causes a decrease in image quality as indicated by increased noise and decreased CNR. To maintain the quality of the image at low tube voltage setting, an IR reconstruction of SAFIRE was used. The purpose of this research is to know the impact of using SAFIRE on dose radiation and image quality of thorax MSCT.Methods: This study was an experimental study with a quasi-experimental study design. The object used was the N-1 Lungman chest phantom in which an artificial tumor was attached. Radiation dose assessment used CTDI value, while image quality assessment used noise and CNR. Data processing was conducted using linear regression test.Results: There was an effect of tube voltage setting and SAFIRE setting on radiation dose and image quality.Conclusions: Tube voltage ssetting and SAFIRE setting had an effect on radiation dose and image quality. Tube voltage setting and SAFIRE strength level setting that were able to provide optimal radiation dose and image quality were tube voltage of 80 kVp and SAFIRE strength levels 3 and 4 (S3 and S4). 

scholarly journals Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Marian S. Solbak ◽  
Mette K. Henning ◽  
Andrew England ◽  
Anne C. Martinsen ◽  
Trond M. Aaløkken ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Contrast Enhancement ◽  
Iodine Concentration ◽  
Ct Dose ◽  
Thoracic Ct ◽  
Thoracic Computed Tomography ◽  
Tube Potential ◽  
Dose Modulation ◽  
The Impact

Abstract Background We investigated the impact of varying contrast medium (CM) densities and x-ray tube potentials on contrast enhancement (CE), image quality and radiation dose in thoracic computed tomography (CT) using two different scanning techniques. Methods Seven plastic tubes containing seven different CM densities ranging from of 0 to 600 HU were positioned inside a commercial chest phantom with padding, representing three different patient sizes. Helical scans of the phantom in single-source mode were obtained with varying tube potentials from 70 to 140 kVp. A constant volume CT dose index (CTDIvol) depending on phantom size and automatic dose modulation was tested. CE (HU) and image quality (contrast-to-noise ratio, CNR) were measured for all combinations of CM density and tube potential. A reference threshold of CE and kVp was defined as ≥ 200 HU and 120 kVp. Results For the medium-sized phantom, with a specific CE of 100–600 HU, the diagnostic CE (200 HU) at 70 kVp was ~ 90% higher than at 120 kVp, for both scan techniques (p < 0.001). Changes in CM density/specific HU together with lower kVp resulted in significantly higher CE and CNR (p < 0.001). When changing only the kVp, no statistically significant differences were observed in CE or CNR (p ≥ 0.094), using both dose modulation and constant CTDIvol. Conclusions For thoracic CT, diagnostic CE (≥ 200 HU) and maintained CNR were achieved by using lower CM density in combination with lower tube potential (< 120 kVp), independently of phantom size.

THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY

2018 ◽  
Vol 185 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Abdulaziz A Qurashi ◽  
Louise A Rainford ◽  
Khalid M Alshamrani ◽  
Shane J Foley
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Organ Dose ◽  
Oxide Semiconductor ◽  
Obese Patients ◽  
Dose Length Product ◽  
Organ Doses ◽  
The Impact

Abstract The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4–L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.

scholarly journals Paediatric head computed tomography dose values and the impact on image quality

2021 ◽  
Vol 31 (Supplement_2) ◽  
Author(s):  
Rafaela Meneses ◽  
Bruno Dias ◽  
Andrea Pimenta ◽  
Graciano Paulo ◽  
Joana Santos
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Image Quality Assessment ◽  
Ct Scanner ◽  
Reference Levels ◽  
Acquisition Mode ◽  
Paediatric Age ◽  
Computed Tomography Dose Index ◽  
The Impact ◽  
Head Computed Tomography

Abstract Background The purpose of this study is to analyse paediatric head Computed Tomography (CT) examination dose values, establish local Diagnostic Reference Levels (DRL), and perform objective image quality assessment per categorisation. Methods A total of 100 paediatric head CT examinations divided into 5 paediatric age categorisations were retrospectively selected: 0–3months, 3months to 1 year, 1 to 6 years, and more than 6 years. Computed Tomography Dose Index (CTDIvol - mGy) and Dose Lenght Product (DLP – mGy.cm), acquisition mode and CT scanner were collected per examination. Examinations with lower and higher dose values per categorisation were selected, and 10 Regions of Interest (ROI’s) were defined on supra and infra tentorial regions in order to access image quality, based on signal and noise values. Local DRLs were compare with the literature and with previous studies of this centre. Results The obtained DLP values were 580, 570, 700, 754 mGy.cm, for the categorisation of 0–3 months, 3 months to 1 year, 1 to 6 years, and more than 6 years, respectively. No significant differences were founded in dose values and image quality, per paediatric categorisation. Conclusions Despise previous local DRLs were defined using a different age categorisation, some paediatric aged categorisation revealed an increase of the dose values. These results must be related with the acquisition of a new CT scanner. Optimisation process is on-going and new protocols are being define.

Effect of Thermal Insulation on Image Quality and Radiation Dose in Polytrauma Computed Tomography

2020 ◽  
Vol 71 (2) ◽  
pp. 238-243
Author(s):  
Paweł Podsiadło ◽  
Robert Chrzan ◽  
Grzegorz Liszka ◽  
Tomasz Sanak ◽  
Sylweriusz Kosiński ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Thermal Insulation ◽  
Noise Intensity ◽  
Independent Risk Factor ◽  
Ct Scans ◽  
Self Heating ◽  
The Impact ◽  
Image Homogeneity

Purpose: Unintentional drop in body temperature in trauma victims is an independent risk factor for mortality. We aimed to assess the impact of thermal insulation on image quality and radiation dose in polytrauma computed tomography (CT). Methods: Thirteen different insulating covers were used to wrap CT phantoms. Images were assessed subjectively at a radiological workstation and analyzed digitally with dedicated software evaluating the noise intensity, spatial resolution, and image homogeneity. The radiation dose was measured using a dosimeter. Results: Most materials did not cause significant artifacts apart from 2 heating pads. Although the radiation dose was increased by the majority of insulating covers (up to 64.66%), certain covers decreased the absorbed radiation (up to −7.35%). Conclusions: The majority of insulating systems do not cause artifacts in CT scans. When using covers with self-heating warmers, removing the heating pad is suggested due to the risk of considerable artifacts appearing. Certain insulating covers may increase or decrease the radiation dose.

Using 100- instead of 120-kVp computed tomography to diagnose pulmonary embolism almost halves the radiation dose with preserved diagnostic quality

2010 ◽  
Vol 51 (3) ◽  
pp. 260-270 ◽  
Author(s):  
Peter Björkdahl ◽  
Ulf Nyman
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Ct Number ◽  
Subjective Image Quality ◽  
Diagnostic Quality ◽  
X Ray ◽  
Tube Potential

Background: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. Purpose: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). Material and Methods: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp ( n = 50) and 120 kVp ( n = 50) 16-MDCT using a “quality reference” effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDIvol) and dose–length product (DLP) were presented by the CT software, and effective dose was estimated. Results: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR −6% and 0%, and CTDIvol −38% and −40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. Conclusion: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals.

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