scholarly journals Studies on the radiation dose, image quality and low contrast detectability from MSCT abdomen by using low tube voltage

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
A. Mokhtar ◽  
Z. A. Aabdelbary ◽  
A. Sarhan ◽  
H. M. Gad ◽  
M. T. Ahmed
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Statistical Significance ◽  
Image Noise ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Low Tube Voltage ◽  
Tube Current ◽  
Noise Ratio

Abstract Background To study radiation dose, image quality and low-contrast cylinder detectability from multislice CT (MSCT) abdomen by using low tube voltage using the American College of Radiology (ACR) phantom. The ACR phantom (low-contrast module) was scanned with 64 MSCT scanner (Brilliance, Philips Medical System, Eindhoven, Netherlands) with 80 and 120 KVP, utilizing different tube current time product (mAs) range from 50 to 380 mAs. The image noise (SD), signal to noise ratio, contrast-to-noise ratio (CNR), and scores of low contrast detectability were assessed for every image respectively. Results From images analyses, the noise essentially increased with the use of low tube voltage. The CNR was 0.94 ± 0.27 at 120 KVP, and CNR was 0.43 ± 0.22 at 80 KVP. However, with the same dose, there were no differences of statistical significance in scores of low-contrast detectability between 120 KVP at 300mAs and 80 KVP at (200–380) mAs (p > 0.05). At 300 mAs, the CTDIvol obtained at 80 KVP was about 29% of that at 120 KVP. The CTDIvol obtained at 80 KVP were decreased from 5% at 50 mAs, to 37% at 380 mAs. Conclusions There is a possibility to decrease exposure of radiation virtually by reducing KVP from 120 to 80 KVP in examination of abdominal CT when the high tube current is used, though increasing image noise at low tube voltage.

Performance Evaluation of Two Iterative Reconstruction Algorithms--MBIR and ASIR, in Low Radiation Dose and Low Contrast Dose Abdominal CT in Children

2019 ◽  
Author(s):  
Jihang Sun ◽  
Lixin Yang ◽  
Zuofu Zhou ◽  
Dan Zhang ◽  
Wei Han ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Image Noise ◽  
Abdominal Ct ◽  
Low Contrast ◽  
Low Radiation Dose ◽  
Contrast Dose ◽  
Contrast Enhanced Ct ◽  
Noise Ratio

Abstract Background The adverse effect of low-dose CT on image quality may be mitigated using iterative reconstructions. The purpose of this study was to evaluate the performance of the full model-based iterative reconstruction (MBIR) and adaptive statistical reconstruction (ASIR) algorithms in low radiation dose and low contrast dose abdominal contrast-enhanced CT (CECT) in children. Methods A total of 59 children (32 males and 27 females) undergoing low radiation dose (100kVp) and low contrast dose (270 mgI/ml) abdominal CECT were enrolled. The median age was 4.0 years (ranging from 0.3 to 13 years). The raw data were reconstructed with MBIR, ASIR and filtered back projection (FBP) algorithms into 6 groups (MBIR, 100%ASIR, 80%ASIR, 60%ASIR, 40%ASIR and FBP). The CT numbers, standard deviations, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of liver, pancreas, kidney and abdominal aorta were measured. Two radiologists independently evaluated the subjective image quality including the overall image noise and structure display ability on a 4-point scale with 3 being clinically acceptable. The measurements among the reconstruction groups were compared using one-way ANOVA. Results The overall image noise score and display ability were 4.00±0.00 and 4.00±0.00 with MBIR, and 3.27±0.33 and 3.25±0.43 with ASIR100%, respectively, which met the diagnostic requirement; other reconstructions couldn’t meet the diagnostic requirements. Compared with FBP images, the noise of MBIR images was reduced by 62.86%-65.73% for the respective organs (F=48.15-80.47, P<0.05), and CNR increased by 151.38%-170.69% (F=22.94-38.02, P<0.05). Conclusions MBIR or ASIR100% improves the image quality of low radiation dose and contrast dose abdominal CT in children to meet the diagnostic requirements, and MBIR has the best performance.

Optimisation of CT scan parameters to increase the accuracy of gross tumour volume identification in brain radiotherapy

2020 ◽  
pp. 1-5
Author(s):  
Kosar Estak ◽  
Mohammad Mohammadzadeh ◽  
Nahideh Gharehaghaji ◽  
Tohid Mortezazadeh ◽  
Rahim Khatyal ◽  
...  
Keyword(s):  
Image Quality ◽  
Tumour Volume ◽  
Standard Protocol ◽  
Gross Tumour Volume ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Brain Radiotherapy ◽  
Tube Current ◽  
Tube Current Time Product

Abstract Aim: This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed. Materials and methods: A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method. Results: Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%). Findings: CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.

scholarly journals The feasibility of low-concentration contrast and low tube voltage in computed tomography perfusion imaging: an animal study

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Yuning Pan ◽  
Aiqin Song ◽  
Shizhong Bu ◽  
Zhaoqian Chen ◽  
Qiuli Huang ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Perfusion Imaging ◽  
Ct Perfusion ◽  
Iodine Intake ◽  
Tube Voltage ◽  
Effective Radiation Dose ◽  
Low Concentration ◽  
Low Tube Voltage ◽  
Effective Radiation

Aim: To investigate the feasibility of low-concentration contrast (270 mg/ml) together with low tube voltage (80 kV) and adaptive iterative dose reduction (AIDR)-3D reconstruction in liver computed tomography (CT) perfusion imaging. Method: A total of 15 healthy New Zealand rabbits received two CT scans each. The first scan (control) was acquired at 100 kV and 100 mA with iopromide (370 mg/ml), while the second scan (experimental) was acquired at 80 kV and 100 mA with iodixanol (270 mg/ml) 24 h after the first scan. The obtained images were reconstructed with filtered back projection (FBP) and AIDR-3D in the control and experimental groups respectively. The perfusion parameters (hepatic artery perfusion [HAP], portal vein perfusion [PVP], hepatic perfusion index [HPI], and total liver perfusion [TLP]) and image quality (image quality score, average CT value of abdomen aorta, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and figure of merit [FOM]) were compared using a paired t-test or Mann–Whitney U test between the two groups, when appropriate. The effective radiation dose and iodine intake were also recorded and compared. Results: With the exception of the FOM criteria, the image quality and perfusion parameters were not significantly different between the two groups. The effective radiation dose and iodine intake were 38.79% and 27.03% lower respectively, in the experimental group. Conclusion: Low-concentration contrast (iodixanol, 270 mg/ml) together with low tube voltage (80 kV) and AIDR-3D reconstruction help to reduce radiation dose and iodine intake without compromising perfusion parameters and image quality in liver CT perfusion imaging.

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