Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner

Arabi, Hossein; Kamali-Asl, Alireza; Ay, Mohammad Reza; Zaidi, Habib

doi:10.1016/j.ejmp.2015.03.014

Cited by 6 publications

(5 citation statements)

References 12 publications

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“…The loss of definition (resolution), arising from infinite focal spot limitation, occurs because of penumbra effect, which is a region partially irradiated (imperfect shadow) by xrays not originating from a point source. Technically, magnification introduces a trade-off between detector sampling resolution and geometric unshaprness (Arabi et al, 2015;Kamali-Asl et al, 2009). Therefore, the spatial resolution is greatly limited by the penumbra effect at high magnification.…”

Section: Discussionmentioning

confidence: 99%

Design and construction of a variable resolution cone-beam small animal mini-CT prototype for in vivo studies

Lohrabian

Kamali-Asl

Arabi

et al. 2019

Radiation Physics and Chemistry

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We present the conceptual design and construction of a mini x-ray computed tomography (mini-CT) scanner designed and built for in vivo small-animal imaging. The imaging system includes an x-ray tube with 0.5 mm focal spot size and a flat panel detector that provides an active area of 41 × 41 cm 2 with 200 µm × 200 µm pixel size. The scanner, designed based on the rotating sample idea, features variable imaging magnification and fieldof-view (FOV). To this end, the detector and x-ray tube are mounted on linear motion systems, such that the object to detector or object to x-ray source distance can be easily changed. The variable magnification enables to acquire images at different spatial resolution depending on the size of the object being imaged. This design provides a trade-off between the scanner's FOV and imaging spatial resolution in which small objects are imaged at relatively high spatial resolution as smaller FOVs are required. Conversely, larger objects can also be imaged as the scanner's FOV is adjustable at the expense of spatial resolution degradation. The scanner's FOV varies from 43 cm down to 9 cm (in diameter) with a spatial resolution improving from 3.9 cycle/mm up to 14.4 cycle/mm, respectively. This mini-CT scanner is a self-standing versatile imager suitable for various preclinical imaging applications.

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Section: Discussionmentioning

confidence: 99%

Design and construction of a variable resolution cone-beam small animal mini-CT prototype for in vivo studies

Lohrabian

Kamali-Asl

Arabi

et al. 2019

Radiation Physics and Chemistry

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“…There have been always interests in designing detectors with the highest possible sensitivity (to detect very low activity concentration) and high spatial resolution (to localize the spatial distribution of the activity concentration). Normally, there is a fundamental tradeoff between improvements in sensitivity and spatial resolution of a detector, wherein strategies such as reducing the field of view (FOV) or modifying the distances between detector, object, and X-ray source (variable magnification) have been adopted to find an optimal compromise between these two key parameters (Lohrabian et al, 2019;Arabi et al, 2015;Arabi, KAMALIASL, Aghamiri;Kamali-Asl et al, 2009;Arabi et al, 2011;Sanaat et al, 2020).…”

Section: This Parameter Defines the Capability Of The Detector To Dis...mentioning

confidence: 99%

Comparison of the X-ray tube spectrum measurement using BGO, NaI, LYSO, and HPGe detectors in a preclinical mini-CT scanner: Monte Carlo simulation and practical experiment

Lohrabian¹,

Kamali-Asl²,

Harvani

et al. 2021

Radiation Physics and Chemistry

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“…[ 7 8 ] CT imaging is an accurate and noninvasive method for detecting abnormalities, including tumors, bone fractures, and cardiovascular diseases. [ 9 10 11 12 ] Recently, an extended range of clinical studies has been performed on the potentials of CT imaging for the diagnosis and management of patients with COVID-19 disease. These studies, in fact, continue to fully identify the underlying COVID-19 features in CT images.…”

Section: Introductionmentioning

confidence: 99%

“…[ 15 ] A recent study showed that DNA double-strand breaks and chromosome aberrations would increase in patients who undergo standard-dose CT scans, while there was no DNA damage in people who have been examined with low-dose CT scans. [ 16 ] Despite the significant advances made in software and hardware technology of CT scanners,[ 17 18 ] it is not yet considered a low-dose safe imaging modality. [ 19 ] Therefore, regarding CT scan's side effects,[ 20 ] the application of low-dose CT protocols would be of crucial importance in routine CT imaging.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of Image Quality in Low-Dose Computed Tomography Imaging for COVID-19 Patients

Behrooz

Karimian

Mostafapour

et al. 2023

Journal of Medical Signals &Amp; Sensors

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Background: Computed tomography (CT) scan is one of the main tools to diagnose and grade COVID-19 progression. To avoid the side effects of CT imaging, low-dose CT imaging is of crucial importance to reduce population absorbed dose. However, this approach introduces considerable noise levels in CT images. Methods: In this light, we set out to simulate four reduced dose levels (60% dose, 40% dose, 20% dose, and 10% dose) of standard CT imaging using Beer–Lambert's law across 49 patients infected with COVID-19. Then, three denoising filters, namely Gaussian, bilateral, and median, were applied to the different low-dose CT images, the quality of which was assessed prior to and after the application of the various filters via calculation of peak signal-to-noise ratio, root mean square error (RMSE), structural similarity index measure, and relative CT-value bias, separately for the lung tissue and whole body. Results: The quantitative evaluation indicated that 10%-dose CT images have inferior quality (with RMSE = 322.1 ± 104.0 HU and bias = 11.44% ± 4.49% in the lung) even after the application of the denoising filters. The bilateral filter exhibited superior performance to suppress the noise and recover the underlying signals in low-dose CT images compared to the other denoising techniques. The bilateral filter led to RMSE and bias of 100.21 ± 16.47 HU and − 0.21% ± 1.20%, respectively, in the lung regions for 20%-dose CT images compared to the Gaussian filter with RMSE = 103.46 ± 15.70 HU and bias = 1.02% ± 1.68% and median filter with RMSE = 129.60 ± 18.09 HU and bias = −6.15% ± 2.24%. Conclusions: The 20%-dose CT imaging followed by the bilateral filtering introduced a reasonable compromise between image quality and patient dose reduction.

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Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner

Cited by 6 publications

References 12 publications

Design and construction of a variable resolution cone-beam small animal mini-CT prototype for in vivo studies

Design and construction of a variable resolution cone-beam small animal mini-CT prototype for in vivo studies

Comparison of the X-ray tube spectrum measurement using BGO, NaI, LYSO, and HPGe detectors in a preclinical mini-CT scanner: Monte Carlo simulation and practical experiment

Quantitative Analysis of Image Quality in Low-Dose Computed Tomography Imaging for COVID-19 Patients

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