Radiation Dose Consideration in Kidney Stone CT Examinations: Integration of Iterative Reconstruction Algorithms With Routine Clinical Practice

ABSTRACTObjectivesRecently concerns have been expressed regarding the cancer risk to patients undergoing CT scanning prompting the development of dose-reducing software. Experimental studies using phantoms, have shown the potential to significantly reduce radiation dose without compromising diagnostic accuracy. However since dose reduction requires acceptance of more noise in the image the findings from these studies may not be representative of the impact in routine clinical practice. The aim of this study was to evaluate the effect of introduction of iterative reconstruction software on radiation dosimetry in routine clinical practice over a range of CT examinationsApproachRandom samples of CT scans pertaining to 10 commonly performed CT examination types undertaken at two hospitals in Western Australia (WA), before and after the introduction of iterative reconstruction software were extracted from the WA centralised Picture Archiving Communication System. Technical information about the scanning parameters used and radiation dose metrics were extracted from the Digital Imaging and Communications in Medicine (DICOM) information contained in the meta-data for each examination. Changes in the mean dose length product and effective dose were evaluated along with estimations of associated changes to annual cancer incidence using established radiation dosimetry techniques.ResultsWe observed statistically significant reductions in the effective radiation dose for head CT (22-27%) consistent with those reported in the literature. In contrast the reductions observed for non-contrast chest (37-47%); chest pulmonary embolism study (28%), chest/abdominal/pelvic study (16%) and thoracic spine (39%) CT were lower than expected based on experimental studies. Statistically significant reductions in radiation dose were not identified in angiographic CT. Dose reductions translated to substantial lowering of the lifetime attributable risk, especially for younger females, and estimated numbers of incident cancers. ConclusionsOur study has demonstrated a reduction in radiation dose for some scanning protocols, but not to the extent experimental studies had previously shown or in all protocols expected, raising questions about the extent to which iterative reconstruction achieves dose reduction in real world clinical practice. In addition, our study showcases a practical application of the use of technical meta-data from CT scanning examinations to monitor radiation dose and evaluate the impact of dose reduction initiatives. These readily available data provide the ability to routinely monitor CT radiation dose (within and between providers) and, when linked to other administrative data, the opportunity to conduct large scale whole-of-population epidemiological studies evaluating the effect policies and practice on population radiation dose and cancer risk.

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Image quality in coronary computed tomography angiography: influence of adaptive statistical iterative reconstruction at various radiation dose levels

Acta Radiologica ◽

10.1177/0284185117753657 ◽

2018 ◽

Vol 59 (10) ◽

pp. 1194-1202 ◽

Cited By ~ 3

Author(s):

Helle Precht ◽

Oke Gerke ◽

Jesper Thygesen ◽

Kenneth Egstrup ◽

Søren Auscher ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Dose ◽

Iterative Reconstruction ◽

Quality Criteria ◽

Left Ventricular ◽

Reconstruction Algorithms ◽

Adaptive Statistical Iterative Reconstruction ◽

Low Contrast ◽

Statistical Iterative Reconstruction

Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32–0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02–1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01–1.12; P = 0.034) compared to FBP. Conclusion ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.

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Reducing Ionizing Radiation Dose during Ct-Guided Percutaneous Drainage of Pelvic Collections and Abscesses Using Iterative Reconstruction Algorithms: Preliminary Experience

Open Access Journal of Clinical Surgery ◽

10.51931/oajcs.2021.02.000035 ◽

2021 ◽

Vol 2 (4) ◽

Author(s):

Andrea Contegiacomo

Keyword(s):

Radiation Dose ◽

Ionizing Radiation ◽

Iterative Reconstruction ◽

Percutaneous Drainage ◽

Reconstruction Algorithms ◽

Ct Guided

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Development of Limited-Angle Iterative Reconstruction Algorithms with Context Encoder-Based Sinogram Completion for Micro-CT Applications

Sensors ◽

10.3390/s18124458 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4458 ◽

Cited By ~ 2

Author(s):

Shih-Chun Jin ◽

Chia-Jui Hsieh ◽

Jyh-Cheng Chen ◽

Shih-Huan Tu ◽

Ya-Chen Chen ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Iterative Reconstruction ◽

Micro Ct ◽

Reconstruction Algorithms ◽

Generative Adversarial Network ◽

Adversarial Network ◽

Novel Approach ◽

Ct System ◽

Limited Angle

Limited-angle iterative reconstruction (LAIR) reduces the radiation dose required for computed tomography (CT) imaging by decreasing the range of the projection angle. We developed an image-quality-based stopping-criteria method with a flexible and innovative instrument design that, when combined with LAIR, provides the image quality of a conventional CT system. This study describes the construction of different scan acquisition protocols for micro-CT system applications. Fully-sampled Feldkamp (FDK)-reconstructed images were used as references for comparison to assess the image quality produced by these tested protocols. The insufficient portions of a sinogram were inpainted by applying a context encoder (CE), a type of generative adversarial network, to the LAIR process. The context image was passed through an encoder to identify features that were connected to the decoder using a channel-wise fully-connected layer. Our results evidence the excellent performance of this novel approach. Even when we reduce the radiation dose by 1/4, the iterative-based LAIR improved the full-width half-maximum, contrast-to-noise and signal-to-noise ratios by 20% to 40% compared to a fully-sampled FDK-based reconstruction. Our data support that this CE-based sinogram completion method enhances the efficacy and efficiency of LAIR and that would allow feasibility of limited angle reconstruction.

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