Deriving the Effective Atomic Number with a Dual-Energy Image Set Acquired by the Big Bore CT Simulator

Jung, Sung-Eun; Kim, Bitbyeol; Kim, Jung In; Choi, Cheol Young

doi:10.14407/jrpr.2020.45.4.171

Cited by 4 publications

(4 citation statements)

References 16 publications

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“…Jung et al reported that the stoichiometric calibration can enhance the accuracy of EAN [ 16 ]. Further, Bourque et al demonstrated that stoichiometric calibration can improve the accuracy of RED without requiring spectral measurements or linear hardening corrections [ 17 ].…”

Section: Methodsmentioning

confidence: 99%

Improving the Accuracy of the Effective Atomic Number (EAN) and Relative Electron Density (RED) with Stoichiometric Calibration on PCD-CT Images

Son

Kim

Lee

2022

Sensors

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The photon counting detector (PCD) in computed tomography (CT) can count the number of incoming photons in order to obtain energy information for photons corresponding to user-defined thresholds. Research on the extraction of effective atomic number (EAN) and relative electron density (RED) using dual-energy CT (DECT) is currently underway. This study proposes a method for improving EAN and RED accuracy of tissue-equivalent materials by using PCD-CT-based stoichiometric calibration. After obtaining DECT images in energy bin (EB) and full spectrum (FS) modes for eight tissue-equivalent materials, the EAN was calculated with stoichiometric calibration. Using the EAN image, the RED image was acquired to evaluate the accuracy. The errors of both EAN and RED obtained with EB were within 4%. In particular, the accuracy of RED was higher than that of the FS method. Study results indicate that PCD-CT contributes to improving EAN and RED accuracy. Further studies will be aimed at reducing ring artifacts by pixel-correcting PCD images and improving stopping power ratio (SPR) measurements for dose calculation in particle therapy.

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Section: Methodsmentioning

confidence: 99%

Improving the Accuracy of the Effective Atomic Number (EAN) and Relative Electron Density (RED) with Stoichiometric Calibration on PCD-CT Images

Son

Kim

Lee

2022

Sensors

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“…Recently, considerable efforts have been made to reduce the uncertainty of dose calculation using dual-energy computed tomography (DECT) [5][6][7]. As an extension of photon dose calculation, the method using electron density and effective atomic number can be employed to that of particles [8][9][10][11][12][13][14]. Zhu et al estimated SPR using effective atomic number (Z eff ) from DECT [8].…”

Section: Introductionmentioning

confidence: 99%

“…The difference reduced to 1.4% for DECT, compared to 5.7% for SECT, demonstrated that the method using DECT resulted in improved material discrimination. Jung et al [13]. obtained Z eff using two SECT scans that may be replaced with a single DECT.…”

Section: Introductionmentioning

confidence: 99%

Algorithm for Using Dual Energy Computed Tomography to Determine Chemical Composition: A Feasibility Study

Choi

Ahn

Park

et al. 2023

Preprint

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Purpose Using dual-energy computed tomography (CT), this study aims to develop an algorithm to identify the chemical constituents of an unknown material (compound or mixture) and improve the accuracy of material discrimination. Methods The algorithm requires mass attenuation coefficients that were obtained using a dual energy CT as an input, identifies the elemental composition, and then calculates its weight fraction. To evaluate the functionality of the developed algorithm, it was used to determine the chemical constituents for human tissues. Furthermore, the results were compared with those provided by the National Institute of Standards and Technology (NIST). We used dual energies 80/140 kVp for spectral CT scans, as inputs to the algorithm, in addition to a set of 50/80 and 80/100 keV for mono-energetic X-rays. Results The algorithm correctly determined the chemical constituent elements of unknown materials. Results were obtained for the fractional weights of each component for mono-energetic X-rays and spectral X-ray use. For mono-energetic X-rays, the differences were < 0.01% for compounds and 6.02% for mixture, respectively. For the spectral X-rays, the differences in 2.98% for compounds and 6.03% for mixtures, respectively. Conclusions We developed an algorithm to determine the type and weight fraction of an element using the MAC of dual-energy CT. The algorithm can exclude the inherent uncertainty of SPR calculations and improve the accuracy of dose calculations in radiation therapy planning.

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“…Over the last few decades, the technical improvement of dual-energy computed tomography (DECT) has led many researchers to suggest the utility and implementation of DECT to improve the accuracy of dose calculation in treatment planning systems as well as the use of Monte Carlo simulation for proton and heavy ion therapy [1,2]. By pairing a low energy and a high energy CT image, DECT can estimate more accurate relative electron density (RED), effective atomic number (EAN), and stopping power ratio (SPR) than conventional single energy CT (SECT) [1,3].…”

Section: Introductionmentioning

confidence: 99%

Effect of Total Collimation Width on Relative Electron Density, Effective Atomic Number, and Stopping Power Ratio Acquired by Dual-Layer Dual-Energy Computed Tomography

Jung

Kim

Yoon

et al. 2021

Progress in Medical Physics

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This study aimed to evaluate the effect of collimator width on effective atomic number (EAN), relative electron density (RED), and stopping power ratio (SPR) measured by dual-layer dual-energy computed tomography (DL-DECT).Methods: CIRS electron density calibration phantoms with two different arrangements of material plugs were scanned by DL-DECT with two different collimator widths. The first phantom included two dense bone plugs, while the second excluded dense bone plugs. The collimator widths selected were 64 mm×0.625 mm for wider collimators and 16 mm×0.625 mm for narrow collimators. The scanning parameters were 120 kVp, 0.33 second gantry rotation, 3 mm slice thickness, B reconstruction filter, and spectral level 4. An image analysis portal system provided by a computed tomography (CT) manufacturer was used to derive the EAN and RED of the phantoms from the combination of low energy and high energy CT images. The EAN and RED were compared between the images scanned using the two different collimation widths. Results:The CT images with the wider collimation width generated more severe artifacts, particularly with high-density material (i.e., dense bone). RED and EAN for tissues (excluding lung and bones) with the wider collimation width showed significant relative differences compared to the theoretical value (4.5% for RED and 20.6% for EAN), while those with the narrow collimation width were closer to the theoretical value of each material (2.2% for EAN and 2.3% for RED). Scanning with narrow collimation width increased the accuracy of SPR estimation even with highdensity bone plugs in the phantom. Conclusions:The effect of CT collimation width on EAN, RED, and SPR measured by DL-DECT was evaluated. In order to improve the accuracy of the measured EAN, RED, and SPR by DL-DECT, CT scanning should be performed using narrow collimation widths.

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Deriving the Effective Atomic Number with a Dual-Energy Image Set Acquired by the Big Bore CT Simulator

Cited by 4 publications

References 16 publications

Improving the Accuracy of the Effective Atomic Number (EAN) and Relative Electron Density (RED) with Stoichiometric Calibration on PCD-CT Images

Improving the Accuracy of the Effective Atomic Number (EAN) and Relative Electron Density (RED) with Stoichiometric Calibration on PCD-CT Images

Algorithm for Using Dual Energy Computed Tomography to Determine Chemical Composition: A Feasibility Study

Effect of Total Collimation Width on Relative Electron Density, Effective Atomic Number, and Stopping Power Ratio Acquired by Dual-Layer Dual-Energy Computed Tomography

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