Dose reduction with iterative reconstruction in multi-detector CT: What is the impact on deformation of circular structures in phantom study?

Objective. This study aims to assess the impact of adaptive statistical iterative reconstruction (ASIR) on CT imaging quality, diagnostic interpretability, and radiation dose reduction for a proven CT acquisition protocol for total body trauma.Methods. 18 patients with multiple trauma (ISS≥16) were examined either with a routine protocol (n=6), 30% (n=6), or 40% (n=6) of iterative reconstruction (IR) modification in the raw data domain of the routine protocol (140 kV, collimation: 40, noise index: 15). Study groups were matched by scan range and maximal abdominal diameter. Image noise was quantitatively measured. Image contrast, image noise, and overall interpretability were evaluated by two experienced and blinded readers. The amount of radiation dose reductions was evaluated.Results. No statistically significant differences between routine and IR protocols regarding image noise, contrast, and interpretability were present. Mean effective dose for the routine protocol was25.3±2.9 mSv,19.7±5.8 mSv for the IR 30, and17.5±4.2 mSv for the IR 40 protocol, that is, 22.1% effective dose reduction for IR 30 (P=0.093) and 30.8% effective dose reduction for IR 40 (P=0.0203).Conclusions. IR does not reduce study interpretability in total body trauma protocols while providing a significant reduction in effective radiation dose.

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Evaluating the impact of dose reduction software on Computed Tomography radiation dosimetry using radiology information systems meta data: An example of the use of novel linkable data.

International Journal for Population Data Science ◽

10.23889/ijpds.v1i1.65 ◽

2017 ◽

Vol 1 (1) ◽

Author(s):

Rachael Moorin ◽

Rene Forsyth ◽

Richard Fox

Keyword(s):

Clinical Practice ◽

Radiation Dose ◽

Dose Reduction ◽

Iterative Reconstruction ◽

Radiation Dosimetry ◽

Experimental Studies ◽

Ct Scanning ◽

Meta Data ◽

Reconstruction Software ◽

The Impact

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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Impact of Eye and Breast Shielding on Organ Doses During Cervical Spine Radiography: Design and Validation of MIRD Computational Phantom

Frontiers in Public Health ◽

10.3389/fpubh.2021.751577 ◽

2021 ◽

Vol 9 ◽

Author(s):

Wiam Elshami ◽

Huseyin Ozan Tekin ◽

Shams A. M. Issa ◽

Mohamed M. Abuzaid ◽

Hesham M. H. Zakaly ◽

...

Keyword(s):

Dose Reduction ◽

Absorbed Dose ◽

Relative Difference ◽

Phantom Study ◽

Tissue Cell ◽

Anthropomorphic Phantom ◽

Organ Doses ◽

Target Organs ◽

Cervical Spine Radiography ◽

The Impact

Purpose: The study aimed to design and validate computational phantoms (MIRD) using the MCNPX code to assess the impact of shielding on organ doses.Method: To validate the optimized phantom, the obtained results were compared with experimental results. The validation of the optimized MIRD phantom was provided by using the results of a previous anthropomorphic phantom study. MIRD phantom was designed by considering the parameters used in the anthropomorphic phantom study. A test simulation was performed to compare the dose reduction percentages (%) between the experimental anthropomorphic phantom study and the MCNPX-MIRD phantom. The simulation was performed twice, with and without shielding materials, using the same number and locations of the detector.Results: The absorbed dose amounts were directly extracted from the required organ and tissue cell parts of output files. Dose reduction percentages between the simulation with shielding and simulation without shielding were compared. The highest dose reduction was noted in the thymus (95%) and breasts (88%). The obtained dose reduction percentages between the anthropomorphic phantom study and the MCNPX-MIRD phantom were highly consistent and correlated values with experimental anthropomorphic data. Both methods showed Relative Difference (%) ranges between 0.88 and 2.22. Moreover, the MCNPX-MIRD optimized phantom provides detailed dose analysis for target and non-target organs and can be used to assess the efficiency of shielding in radiological examination.Conclusion: Shielding breasts and eyes during cervical radiography reduced the radiation dose to many organs. The decision to not shield patients should be based on research evidence as this approach does not apply to all cases.

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