Relationships of clinical protocols and reconstruction kernels with image quality and radiation dose in a 128-slice CT scanner: Study with an anthropomorphic and water phantom

2012 ◽  
Vol 81 (5) ◽  
pp. e699-e703 ◽  
Author(s):  
Jijo Paul ◽  
B. Krauss ◽  
R. Banckwitz ◽  
W. Maentele ◽  
R.W. Bauer ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Clinical Protocols ◽  
Ct Scanner ◽  
Water Phantom

scholarly journals Variation in tube voltage for pediatric neck 64VCT: Effect on radiation dose and image quality

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259772
Author(s):  
Li-Guo Chen ◽  
Ping-An Wu ◽  
Hsing-Yang Tu ◽  
Ming-Huei Sheu ◽  
Li-Chuan Huang
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Region Of Interest ◽  
Ct Scanner ◽  
Multidetector Row Ct ◽  
Dose Length Product ◽  
Multidetector Row ◽  
Tube Current ◽  
Noise Measurements ◽  
Unpaired Student

Exposure to ionizing radiation can cause cancer, especially in children. In computed tomography (CT), a trade-off exists between the radiation dose and image quality. Few studies have investigated the effect of dose reduction on image quality in pediatric neck CT. We aimed to assess the effect of peak kilovoltage on the radiation dose and image quality in pediatric neck multidetector-row CT. Measurements were made using three phantoms representative of children aged 1, 5, and 10 years, with tube voltages of 80, 100, and 120 kilovoltage peak (kVp); tube current of 10, 40, 80, 120, 150, 200, and 250 mA; and exposure time = 0.5 s (pitch, 0.984:1). Radiation dose estimates were derived from the dose-length product with a 64-multidetector-row CT scanner. Images obtained from the control protocol (120 kVp) were compared with the 80- and 100-kVp protocols. The effective dose (ED) was determined for each protocol and compared with the 120-kVp protocol. Quantitative analysis entailed noise measurements by recording the standard deviation of attenuation for a circular 1-cm2 region of interest placed on homogeneous soft tissue structures in the phantom. The mean noise of the various kVp protocols was compared using the unpaired Student t-test. Reduction of ED was 37.58% and 68.58% for neck CT with 100 kVp and 80 kVp, respectively. The image noise level increased with the decrease in peak kilovoltage. Noise values were higher at 80 kVp at all neck levels, but did not increase at 100 kVp, compared to 120 kVp in the three phantoms. The measured noise difference was the greatest at 80 kVp (absolute increases<2.5 HU). The subjective image quality did not differ among the protocols. Thus, reducing voltage from 120 to 80 kVp for neck CT may achieve ED reduction of 68.58%, without compromising image quality.

scholarly journals 127 Evaluation of Coronary CT scans radiation dose and image quality using different scanning protocol on a 256-slice CT scanner

2011 ◽  
Vol 3 (1) ◽  
pp. 41
Author(s):  
Patrick Dupouy ◽  
Ahmed Fareed ◽  
Ramon Labbe ◽  
Maher Hakim ◽  
Gérard Haquin ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Scans ◽  
Ct Scanner ◽  
Scanning Protocol ◽  
Coronary Ct

scholarly journals Artificial intelligence-based patient positioning for faster, more accurate and efficient CT imaging for COVID-19 patients

2020 ◽  
Author(s):  
Yadong Gang ◽  
Xiongfeng Chen ◽  
Huan Li ◽  
Hanlun Wang ◽  
Jianying Li ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Imaging ◽  
Image Noise ◽  
Erector Spinae ◽  
Ct Scanner ◽  
Clinical Value ◽  
Positioning Method ◽  
Positioning Time ◽  
Center Distance

Abstract Objective: To analyze and compare the imaging workflow, radiation dose and image quality for COVID-19 patients examined using either the conventional manual positioning method or an AI-based positioning method. Materials and Methods: 127 adult COVID-19 patients underwent chest CT scans on a CT scanner using the same scan protocol except with the manual positioning (MP group) for the initial scan and an AI-based positioning method (AP group) for the follow-up scan. Radiation dose, patient off-center distance, examination and positioning time of the two groups were recorded and compared. Image noise and signal-to-noise ratio (SNR) were assessed by three experienced radiologists and were compared between the two groups.Results: The AP group reduced the total positioning time and examination time by 28% and 8%, respectively compared with the MP group. Compared with the MP group, AP group had significantly less patient off-center distance (AP:1.56cm ± 0.83 vs. MP: 4.05cm ± 2.40, p<0.001) and higher proportion of positioning accuracy (AP: 99% vs. MP: 92%), resulted in 16% radiation dose reduction (AP: 6.1mSv ± 1.3 vs. MP: 7.3mSv ± 1.2, p<0.001) and 9% image noise reduction in erector spinae and lower noise and higher SNR for lesions in the pulmonary peripheral areas.Conclusion: The AI-based positioning and centering in CT imaging is a promising new technique for reducing radiation dose, optimizing imaging workflow and image quality in imaging the chest. This technique has important added clinical value in imaging COVID-19 patients to reduce the cross-infection risks.

scholarly journals Low Dose versus Standard Single Heartbeat Acquisition Coronary Computed Tomography Angiography

2018 ◽  
Vol 8 ◽  
pp. 52
Author(s):  
Ernesto Di Cesare ◽  
Alessandra Di Sibio ◽  
Antonio Gennarelli ◽  
Margherita Di Luzio ◽  
Ines Casazza ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Comparative Analysis ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Computed Tomography Angiography ◽  
Coronary Computed Tomography Angiography ◽  
Ct Scanner ◽  
Diagnostic Quality ◽  
Coronary Computed Tomography

Purpose: The aim of this study was to compare image quality and mean radiation dose between two groups of patients undergoing coronary computed tomography angiography (CCTA) using a 640-slice CT scanner with two protocols with different noise level thresholds expressed as standard deviation (SD). Materials and Methods: Two-hundred and sixty-eight patients underwent a CCTA with 640 slice CT scanner. In the experimental group (135 patients), an SD 51 protocol was employed; in the control group (133 patients), an SD 33 protocol was used. Mean effective dose and image quality with both objective and subjective measures were assessed. Image quality was subjectively assessed using a five-point scoring system. Segments scoring 2, 3, and 4 were considered having diagnostic quality, while segments scoring 0 and 1 were considered having nondiagnostic quality. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between the two groups as well as the effective radiation dose (ED) was finally assessed. Results: Comparative analysis considering diagnostic quality (2, 3, and 4 score) and nondiagnostic (score 0 and 1) quality demonstrated that image quality of SD 51 group is not significantly lower than that of S33 group. The noise was significantly higher in the SD 51 group than in the SD 33 group (P < 0.0001). The SNR and CNR were higher in the SD 33 group than in SD 51 group (P < 0.0001). Mean effective dose was 49% lower in the SD 51 group than in SD 33 group; indeed mean effective dose was 1.43 mSv ± 0.67 in the SD 51 group while it was 2.8 mSv ± 0.57 in the SD 33 group. Conclusion: Comparative analysis shows that using a 640-slice CT with a 51 SD protocol, it is possible to reduce the mean radiation dose while maintaining good diagnostic image quality.

scholarly journals A comparison between manual and artificial intelligence-based automatic positioning in CT imaging for COVID-19 patients

2020 ◽  
Author(s):  
Yadong Gang ◽  
Xiongfeng Chen ◽  
Huan Li ◽  
Hanlun Wang ◽  
Jianying Li ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Imaging ◽  
Image Noise ◽  
Erector Spinae ◽  
Ct Scanner ◽  
Clinical Value ◽  
Automatic Positioning ◽  
Positioning Time ◽  
Center Distance

Abstract Objective: To analyze and compare the imaging workflow, radiation dose and image quality for COVID-19 patients examined using either the conventional manual positioning (MP) method or an AI-based automatic positioning (AP) method. Materials and Methods: 127 adult COVID-19 patients underwent chest CT scans on a CT scanner using the same scan protocol except with the manual positioning (MP group) for the initial scan and an AI-based automatic positioning method (AP group) for the follow-up scan. Radiation dose, patient positioning time and off-center distance, of the two groups were recorded and compared. Image noise and signal-to-noise ratio (SNR) were assessed by three experienced radiologists and were compared between the two groups.Results: The AP operation was successful for all patients in the AP group and reduced the total positioning time by 28% compared with the MP group. Compared with the MP group, the AP group had significantly less patient off-center distance (AP:1.56cm±0.83 vs. MP: 4.05cm±2.40, p<0.001) and higher proportion of positioning accuracy (AP: 99% vs. MP: 92%), resulted in 16% radiation dose reduction (AP: 6.1mSv±1.3 vs. MP: 7.3mSv±1.2, p<0.001) and 9% image noise reduction in erector spinae and lower noise and higher SNR for lesions in the pulmonary peripheral areas.Conclusion: The AI-based automatic positioning and centering in CT imaging is a promising new technique for reducing radiation dose, optimizing imaging workflow and image quality in imaging the chest. This technique has important added clinical value in imaging COVID-19 patients to reduce the cross-infection risks.

scholarly journals Image quality, contrast enhancement and radiation dose of ECG-triggered versus non-ECG-triggered imaging of the aorta on a single source 256-slice CT scanner

2021 ◽  
Author(s):  
YM Wong ◽  
CC Ong ◽  
CR Liang ◽  
CA Tan ◽  
LLS Teo
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Contrast Enhancement ◽  
Aortic Root ◽  
Ascending Aorta ◽  
Single Source ◽  
Ct Scanner ◽  
Noise Ratio ◽  
Group 2 ◽  
Group 1

Introduction: Computed tomography angiography of the aorta (CTAA) is the modality of choice for investigating aortic disease. Our aim was to evaluate image quality, contrast enhancement and radiation dose of electrocardiograph (ECG)-triggered and non-ECG-triggered CTAA on a 256-slice single source CT scanner. Knowledge of these will allow requesting clinician and radiologist to balance radiation risk and image quality. Methods: We retrospectively assessed data from 126 patients who had undergone CTAA on a single-source CT scanner using ECG-triggered (group 1, n = 77) or non-ECG-triggered (group 2, n =49) protocols. Radiation doses were compared. Qualitative (4-point scale) and quantitative image quality assessments were performed. Results: The mean volume CT dose index, dose length product and effective dose in group 1 were 12.4 ± 1.9 mGy, 765.8 ± 112.4 mGy x cm and 13.0 ± 1.9 mSv, respectively. These were significantly higher compared with group 2 (9.1 ± 2.6 mGy, 624.1 ± 174.8 mGy x cm and 10.6 ± 3.0 mSv, respectively) ( p < 0.001). Qualitative assessment showed image quality at the aortic root-proximal ascending aorta was significantly higher in group 1 (median = 3) than in group 2 (median = 2, p < 0.001). Quantitative assessment showed significantly better mean arterial attenuation, signal-to-noise ratio and contrast-to-noise ratio in ECG-triggered CTAA compared with non-ECG-triggered CTAA. Conclusion: ECG-triggered CTAA in a single-source scanner has superior image quality and vessel attenuation of aortic root/ascending aorta but a higher radiation dose of approximately 23%. Its use should be considered specifically when assessing aortic root/ascending aorta pathology.

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