scholarly journals Image quality and lesion detectability in low-dose paediatric 18F-FDG scans using total-body PET/CT

2021 ◽  
Author(s):  
Ying-Ying Hu ◽  
Yu-Mo Zhao ◽  
Tao Chen ◽  
Wei-Guang Zhang ◽  
Lin-Hao Wang ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Low Dose ◽  
Subjective Image Quality ◽  
Full Dose ◽  
Lesion Detectability ◽  
Paediatric Patients ◽  
Pet Ct ◽  
Total Body ◽  
Lesion Conspicuity

Abstract Purpose: To investigate the effects of dose reduction on image quality and lesion detectability of oncological 18F-FDG total-body PET/CT in paediatric oncological patients, and explore the minimum threshold of administered tracer activity.Methods: A total of 33 paediatric patients (weight, 8.5–58.5 kg; age 0.8–17.6 years) underwent total-body PET/CT using uEXPLORER scanner with an 18F-FDG administered dose of 3.7 MBq/kg and an acquisition time of 600 s were retrospectively enrolled. Low-dose images (0.12 – 1.85 MBq/kg) were simulated by truncating the list-mode PET data to reducing count density. Subjective image quality was rated on a 5-point scale. Semi-quantitative uptake metrics for low-dose images were assessed using region-of-interest (ROI) analysis of healthy liver and suspected lesions and were compared to full-dose images. The micro-lesion detectability was compared among the dose-dependent PET images.Results: Our analysis shows that sufficient subjective image quality and lesion conspicuity could be maintained down to 1/30th (0.12 MBq/kg) of the administered dose of 18F-FDG, where good image quality scores were given to 1/2- and 1/10- dose groups. The image noise was significantly more deranged than the overall quality and lesion conspicuity in 1/30- to 1/10-dose groups (all P < 0.05). With reduced doses, quantitative analysis of ROIs showed that SUVmax and SD in the liver increased gradually (P < 0.05), but SUVmax in the lesions and lesion-to-background ratio (LBR) showed no significant deviation down to 1/30-dose. 100% of the 18F-FDG-avid micro-lesions identified in full-dose images were localised down to 1/15-dose images; while 97% of the lesion were localized in 1/30-dose images.Conclusion: The total-body PET/CT might significantly decrease the administered dose upon maintaining the image quality and diagnostic performance of micro-lesions in paediatric patients. Data suggests that using total-body PET/CT, optimal image quality could be achieved with an administered dose-reduction down to 1/10-dose (0.37 MBq/kg).

scholarly journals Influence of a novel deep-learning based reconstruction software on the objective and subjective image quality in low-dose abdominal computed tomography

2021 ◽  
Vol 94 (1117) ◽  
pp. 20200677
Author(s):  
Andrea Steuwe ◽  
Marie Weber ◽  
Oliver Thomas Bethge ◽  
Christin Rademacher ◽  
Matthias Boschheidgen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Dose Reduction ◽  
Low Dose ◽  
Ct Images ◽  
Image Noise ◽  
The Novel ◽  
Subjective Image Quality ◽  
Image Information ◽  
Noise Ratio

Objectives: Modern reconstruction and post-processing software aims at reducing image noise in CT images, potentially allowing for a reduction of the employed radiation exposure. This study aimed at assessing the influence of a novel deep-learning based software on the subjective and objective image quality compared to two traditional methods [filtered back-projection (FBP), iterative reconstruction (IR)]. Methods: In this institutional review board-approved retrospective study, abdominal low-dose CT images of 27 patients (mean age 38 ± 12 years, volumetric CT dose index 2.9 ± 1.8 mGy) were reconstructed with IR, FBP and, furthermore, post-processed using a novel software. For the three reconstructions, qualitative and quantitative image quality was evaluated by means of CT numbers, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in six different ROIs. Additionally, the reconstructions were compared using SNR, peak SNR, root mean square error and mean absolute error to assess structural differences. Results: On average, CT numbers varied within 1 Hounsfield unit (HU) for the three assessed methods in the assessed ROIs. In soft tissue, image noise was up to 42% lower compared to FBP and up to 27% lower to IR when applying the novel software. Consequently, SNR and CNR were highest with the novel software. For both IR and the novel software, subjective image quality was equal but higher than the image quality of FBP-images. Conclusion: The assessed software reduces image noise while maintaining image information, even in comparison to IR, allowing for a potential dose reduction of approximately 20% in abdominal CT imaging. Advances in knowledge: The assessed software reduces image noise by up to 27% compared to IR and 48% compared to FBP while maintaining the image information. The reduced image noise allows for a potential dose reduction of approximately 20% in abdominal imaging.

The image quality, lesion detectability, and acquisition time of 18F-FDG total-body PET/CT in oncological patients

2020 ◽  
Vol 47 (11) ◽  
pp. 2507-2515 ◽  
Author(s):  
Yi-Qiu Zhang ◽  
Peng-Cheng Hu ◽  
Run-Ze Wu ◽  
Yu-Shen Gu ◽  
Shu-Guang Chen ◽  
...  
Keyword(s):  
Image Quality ◽  
Acquisition Time ◽  
Lesion Detectability ◽  
Oncological Patients ◽  
Pet Ct ◽  
18F Fdg ◽  
Total Body

scholarly journals Iterative reconstruction improves image quality and reduces radiation dose in trauma protocols; A human cadaver study

2021 ◽  
Vol 10 (10) ◽  
pp. 205846012110553
Author(s):  
Johannes Clemens Godt ◽  
Cathrine K Johansen ◽  
Anne Catrine T Martinsen ◽  
Anselm Schulz ◽  
Helga M Brøgger ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Human Cadaver ◽  
Full Dose ◽  
Significant Difference ◽  
Noise Ratio ◽  
Dose Levels

Background Radiation-related cancer risk is an object of concern in CT of trauma patients, as these represent a young population. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers. Purpose To compare image quality in human cadaver exposed to thoracoabdominal computed tomography using IR and standard filtered back-projection (FBP) at different dose levels. Material and methods Ten cadavers were scanned at full dose and a dose reduction in CTDIvol of 5 mGy (low dose 1) and 7.5 mGy (low dose 2) on a Siemens Definition Flash 128-slice computed tomography scanner. Low dose images were reconstructed with FBP and Sinogram affirmed iterative reconstruction (SAFIRE) level 2 and 4. Quantitative image quality was analyzed by comparison of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Qualitative image quality was evaluated by use of visual grading regression (VGR) by four radiologists. Results Readers preferred SAFIRE reconstructed images over FBP at a dose reduction of 40% (low dose 1) and 56% (low dose 2), with significant difference in overall impression of image quality. CNR and SNR showed significant improvement for images reconstructed with SAFIRE 2 and 4 compared to FBP at both low dose levels. Conclusions Iterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population.

scholarly journals Feasibility of Low-Dose 68Ga-DOTATATE With Short Acquisition Time Using Total-Body PET/CT in Patients With Neuroendocrine Tumor

2021 ◽  
Author(s):  
Jie Xiao ◽  
Haojun Yu ◽  
Hongyan Yin ◽  
Guobin Liu ◽  
Yan Hu ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Regimen ◽  
Low Dose ◽  
Signal To Noise Ratio ◽  
Subjective Evaluation ◽  
Blood Pool ◽  
Acquisition Time ◽  
Short Acquisition Time ◽  
Pet Ct ◽  
Total Body

Abstract Purpose To explore the feasibility of a low dose regimen with short acquisition time of 68Ga-DOTATATE total-body PET/CT without compromising image quality of patients with NETs. Methods Fifty-seven consecutive NETs patients who underwent 68Ga-DOTATATE total-body PET/CT, with a low dose regimen (0.8-1.2 MBq/kg) of 68Ga-DOTATATE and acquisition time of 10 min prior to any treatment, were enrolled in the present study. The PET data were split into 1 min, 2 min, 3 min, 4 min, 5 min, 8 min and 10 min reconstruction groups, referenced as R1, R2, R3, R4, R5, R8 and R10. The subjective evaluation of image quality was scored in 5-point Likert scale based on three aspects: the overall impression of the image quality, the image noise, the lesion detectability. The objective image quality was assessed by the signal-to-noise ratio of liver (SNRL), the coefficient of variation (CV), the SUVmax, SUVmean, SD of liver, mediastinal blood pool and lesion, the tumor-liver ratio (TLR), the tumor-mediastinal blood pool-ratio (TMR) of lesion. Results The sufficient subjective image quality with a score of 3.44±0.53 could be obtained at 3 min acquisition duration, with a kappa value of 0.90. In quantitative analysis, the value of SNRL is over 10 in all reconstruction groups. As the acquisition time increases, SNRL was increased and CV was decreased within 3 min, while SNRL and CV showed no significant different between R4-R10. There was no significant different in TMR and TLR of lesion between R1-R10 (all p < 0.05). Referenced as PET images of R10, 90 SSTR-positive lesions are identified, and all those lesions are found in the R1-R10 groups (100%).Conclusion The low-dose (0.8-1.2 MBq/kg) 68Ga-DOTATATE total-body PET/CT not only shortens acquisition time, but maintains a sufficient image quality for the NETs patients.

scholarly journals Exploration of Optimal Reconstruction Parameters for 18F-FDG Total-body PET/CT with Ultra-low Activity Injection

2021 ◽  
Author(s):  
Xiuli Sui ◽  
Hui Tan ◽  
Haojun Yu ◽  
Yiqiu Zhang ◽  
Pengcheng Hu ◽  
...  
Keyword(s):  
Image Quality ◽  
Expectation Maximization ◽  
Lesion Size ◽  
Pet Ct ◽  
Quality Image ◽  
Optimal Reconstruction ◽  
Total Body ◽  
Low Activity ◽  
Lesion Conspicuity ◽  
Reconstruction Time

Abstract PURPOSE To explorer the optimal reconstruction parameters in oncologic 18 F-FDG total-body PET/CT studies with ultra-low activity injection. METHODS A total of 204 reconstructed PET images of 34 patients with a total of 58 lesions were analyzed by two experienced nuclear medicine physicians. Images were reconstructed with ordered subset expectation maximization (OSEM) algorithm (2 and 3 iterations) including time-of-flight (TOF) and point spread function (PSF) corrections and regularization ordered subset expectation maximization (ROSEM) (b-values of 0.3, 0.4, 0.5, and 0.6). General image quality was assessed using the five-point method including overall image quality, image clarity, noise, and lesion conspicuity. Image noise, signal-to-noise ratio, lesion size, SUVmax, SUVpeak and T/N were quantitatively analyzed by the third reader who did not participate in subjective image assessment. RESULTS In objective image quality indicators, noise decreased and a continuous increase of SNR with incremental β-values (0.3,0.4, 0.5 and 0.6) compared with OSEM3. In subjective image quality, OSEM2, ROSEM0.5 and ROSEM0.6 scored higher (all P<0.001) in overall image quality, image contrast and noise. The scores of ROSEM reconstructions were all higher in lesion conspicuity compared with OSEM3 (all P<0.001). In lesion detectability, SUVmax, SUVpeak and T/N increase with β value of ROSEM increase. Compared with OSEM3, there was a negative correlation between lesion size and the percentage increase of SUVpeak in OSEM2 and ROSEM reconstructions (all P<0.01). CONCLUSION In clinical practice, we recommended OSEM reconstruction with 3 iterations with a relatively short reconstruction time and we recommend ROSEM algorithm with b of 0.5 when reconstruction time is not considered.

Ultra-Low-Dose CT of the Thorax Using Iterative Reconstruction: Evaluation of Image Quality and Radiation Dose Reduction

2015 ◽  
Vol 204 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Yookyung Kim ◽  
Yoon Kyung Kim ◽  
Bo Eun Lee ◽  
Seok Jeong Lee ◽  
Yon Ju Ryu ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Radiation Dose Reduction ◽  
Low Dose Ct

Determination of a cone-beam CT low-dose protocol for root fracture diagnosis in non-endodontically treated anterior maxillary teeth

2021 ◽  
pp. 20210138
Author(s):  
Fedil Andraws Yalda ◽  
Chrysoula Theodorakou ◽  
Rosalyn J Clarkson ◽  
Jonathan Davies ◽  
Lee Feinberg ◽  
...  
Keyword(s):  
Image Quality ◽  
Diagnostic Accuracy ◽  
Dose Reduction ◽  
Low Dose ◽  
Ex Vivo ◽  
Characteristic Curve ◽  
Ex Vivo Model ◽  
Contrast Resolution ◽  
Anterior Teeth ◽  
Root Fractures

Objectives: The aim of this study was to determine a “low-dose protocol” which provides acceptable diagnostic accuracy for detection of root fractures in unrestored anterior maxillary teeth, using an ex vivo model. Methods: 48 maxillary anterior teeth, half with horizontal or oblique root fractures, were imaged using CBCT in an anthropomorphic model. Nine X-ray exposure combinations were used, including the manufacturer’s standard (“reference”) exposure and high-resolution settings (“HiRes”), by varying kV, exposure time, and rotation angle. Measurements of Dose Area Product (DAP) were recorded. Five dental radiologists assessed the scans for root fractures and judged image quality. Parameters of diagnostic accuracy were calculated, including area under the Receiver Operating Characteristic curve (Az). Objective measures of image quality were made at the same exposure combinations using an image quality phantom. Results: Although there was a significant linear relationship between DAP and mean Az, only the lowest DAP exposure combination had a mean Az significantly different to the reference exposure. There was no significant effect on other diagnostic accuracy parameters when using HiRes compared with the reference exposure. There was a significant positive relationship between DAP and contrast resolution. HiRes did not significantly improve contrast resolution and made a small improvement to spatial resolution. Conclusions: Scope existed for radiation dose reduction compared with the manufacturer’s guidance. There was no improvement in diagnostic accuracy using HiRes settings. A cautious recommendation for this CBCT machine is that it is possible to achieve a dose reduction of about 20% compared with the reference exposure parameters.

Ultra-low-dose lung screening CT with model-based iterative reconstruction: an assessment of image quality and lesion conspicuity

2017 ◽  
Vol 59 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Yun Hye Ju ◽  
Geewon Lee ◽  
Ji Won Lee ◽  
Seung Baek Hong ◽  
Young Ju Suh ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Image Noise ◽  
Low Dose Ct ◽  
Group 5 ◽  
Lung Screening ◽  
Lesion Conspicuity ◽  
Group 1

Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal–Wallis test and the Chi-square test. Results Effective doses were 61–87% lower in groups 2–5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P < 0.001). Overall image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1–3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1–4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.

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