A new contrast-to-noise ratio for image quality characterization of a coded-aperture γ camera

Zhu, Bo; Wang, Zhonghai; Chen, Qi; Huang, Qi-Chang; Mao, Xiaoqin; Zhao, Changsong; Tao, Mingrui; Qi, Peiwen; Qing-hua, Zhao; Li, Yulong; Zhou, Rong; Yang, Chaowen

doi:10.1016/j.apradiso.2021.109592

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…Velocity along 𝑋 direction (mm/s) Velocity along 𝑌 direction (mm/s) of the source along the main diagonal of the grid (figure 5) clearly show that the positions of the brightest pixels are consistent with the ideal hotspot positions given in figure 4. Taking the New Contrast-to-Noise Ratio (New CNR) [20] to assess the one-point source image quality presented…”

Section: One-point Radioactive Source Imagingmentioning

confidence: 99%

A novel method for assessing imaging quality of coded-aperture gamma-ray camera to radioactive plane source

et al. 2023

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With the wide application of the coded-aperture gamma-ray camera in the field of nuclear radiation monitoring, research on its imaging performance of radioactive point sources has increasingly matured. However, because of the difficulty in obtaining complex radioactive plane sources with specific activity distributions, there is a lack of experimental research on imaging performance of such sources currently, the main focus being on simulation research and on-site imaging trials. In addressing the issue, we proposed a method to assess image quality of coded-aperture gamma-ray camera to such sources, and performed imaging experiments with a custom-made gamma-ray camera. Driven by a two-axis computer-numerical control (CNC) motion platform, a point source was moved through prescribed paths at a given velocity, from which a custom activity distribution plane source for coded-aperture imaging was constructed. Peak signal-to-noise ratio and structural index similarity were the two indicators used to evaluate the imaging quality of the plane source for seven distinct shapes. The results indicate that the imaging quality of the plane source imaged by our custom-made camera and constructed using our method is excellent with these two indicators being better than 17 dB and 0.996, respectively. Our method provides good reliability and practicality, and offers an alternative approach for assessing imaging quality of coded-aperture gamma-ray camera for complex radioactive plane sources.

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Section: One-point Radioactive Source Imagingmentioning

confidence: 99%

A novel method for assessing imaging quality of coded-aperture gamma-ray camera to radioactive plane source

et al. 2023

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“…where 𝑆 represents the peak significance of the image, 𝐵 represents the background average level, and 𝜎 represents the background fluctuation. To clarify the oblique irradiation effect, if both the mask thickness and the gamma-ray energy remain constant and the radioactive source moves away from the center of view, the image quality deteriorates [15] because the collimation effect and the penetration effect in the disturbance factor shrinks contributing to more deterioration on background noise when compared with the improvement obtained from the lower transmission background through the opaque element. In addition, when the source moves away from the center of view, because the gamma ray counts that pass through the opaque elements and the hole elements are reduced by the transmission effect, the collimation and the penetration term in the disturbance factor, the accumulated number of counts in the projection image decreases, and the image brightness thus degrades because of the oblique irradiation effect.…”

Section: Jinst 17 T05019mentioning

confidence: 99%

Impact of mask thickness on the imaging performance of the coded-aperture gamma camera

et al. 2022

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Coded-aperture gamma imaging techniques have been applied widely in several radiation monitoring fields. However, in terms of the design of the coded-aperture mask, the category and rank of the mask are generally considered, but there is a lack of detailed research on selection of the appropriate mask thickness. Concretely, the imaging performance is affected by the mask thickness in terms of two factors: the full-field image quality of the overall field of view (FOV), which represents the background noise tolerance of the radioactive source; and the image brightness consistency, which represents consistency of the imaging efficiency. We have studied and analyzed these two imaging performance indexes in relation to the mask thickness based on the model of our custom-made gamma camera. Specifically, the full-field image quality initially improves and later deteriorates with the mask thickness increases from 0.1 mm to 30 mm because of the competition and the tradeoff between the transmission background and the oblique irradiation effect; the image brightness consistency initially descends, then improves, and finally decreases again under the same conditions as a result of the tradeoff between the improvement of the transmission background ratio and deterioration of the oblique irradiation coefficient ratio. Furthermore, these two indexes change trends are both related to gamma-ray energy. Finally, based on a comprehensive analysis of the imaging performance, the optimal thicknesses for the customized W-Cu alloy modified uniformly redundant array masks for 59.5 keV, 662 keV, 1250 keV gamma-ray imaging are 0.5 mm, 10 mm, and 16 mm, respectively.

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Development of a modular high-sensitivity high-uniformity gamma camera for radiation monitoring applications

Zhao

Zhu

Zhao

et al. 2021

Nuclear Instruments and Methods in Physics Research Section A:

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A new contrast-to-noise ratio for image quality characterization of a coded-aperture γ camera

Cited by 5 publications

References 12 publications

A novel method for assessing imaging quality of coded-aperture gamma-ray camera to radioactive plane source

A novel method for assessing imaging quality of coded-aperture gamma-ray camera to radioactive plane source

Impact of mask thickness on the imaging performance of the coded-aperture gamma camera

Development of a modular high-sensitivity high-uniformity gamma camera for radiation monitoring applications

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