Extrapolation of the Bethe equation for electron stopping powers to intermediate and low electron energies by empirical simulation of target effective mean excitation energy and atomic number

2013 ◽  
Vol 316 ◽  
pp. 123-129 ◽  
Author(s):  
I.I. Maglevanny ◽  
V.A. Smolar ◽  
H.T.T. Nguyen
Keyword(s):  
Excitation Energy ◽  
Atomic Number ◽  
Bethe Equation ◽  
Mean Excitation Energy

scholarly journals Calculation of Stopping-Power Ratio from Multiple CT Numbers Using Photon-Counting CT System: Two- and Three-Parameter-Fitting Method

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1215
Author(s):  
Sung Hyun Lee ◽  
Naoki Sunaguchi ◽  
Akie Nagao ◽  
Yoshiyuki Hirano ◽  
Hiroshi Sakurai ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Atomic Number ◽  
Photon Counting ◽  
Effective Atomic Number ◽  
Stopping Power ◽  
Power Ratio ◽  
Mean Excitation Energy ◽  
Fitting Method ◽  
Ct System ◽  
Relative Errors

The two-parameter-fitting method (PFM) is commonly used to calculate the stopping-power ratio (SPR). This study proposes a new formalism: a three-PFM, which can be used in multiple spectral computed tomography (CT). Using a photon-counting CT system, seven rod-shaped samples of aluminium, graphite, and poly(methyl methacrylate) (PMMA), and four types of biological phantom materials were placed in a water-filled sample holder. The X-ray tube voltage and current were set at 150 kV and 40 μμA respectively, and four CT images were obtained at four threshold settings. A semi-empirical correction method that corrects the difference between the CT values from the photon-counting CT images and theoretical values in each spectral region was also introduced. Both the two- and three-PFMs were used to calculate the effective atomic number and electron density from multiple CT numbers. The mean excitation energy was calculated via parameterisation with the effective atomic number, and the SPR was then calculated from the calculated electron density and mean excitation energy. Then, the SPRs from both methods were compared with the theoretical values. To estimate the noise level of the CT numbers obtained from the photon-counting CT, CT numbers, including noise, were simulated to evaluate the robustness of the aforementioned PFMs. For the aluminium and graphite, the maximum relative errors for the SPRs calculated using the two-PFM and three-PFM were 17.1% and 7.1%, respectively. For the PMMA and biological phantom materials, the maximum relative errors for the SPRs calculated using the two-PFM and three-PFM were 5.5% and 2.0%, respectively. It was concluded that the three-PFM, compared with the two-PFM, can yield SPRs that are closer to the theoretical values and is less affected by noise.

scholarly journals Deriving the mean excitation energy map from dual-energy and proton computed tomography

2018 ◽  
Vol 6 ◽  
pp. 20-24 ◽  
Author(s):  
Gloria Vilches-Freixas ◽  
Catherine Therese Quiñones ◽  
Jean Michel Létang ◽  
Simon Rit
Keyword(s):  
Computed Tomography ◽  
Excitation Energy ◽  
Dual Energy ◽  
Mean Excitation Energy ◽  
Proton Computed Tomography ◽  
The Mean

Determination of the mean excitation energy of water from proton beam ranges

2007 ◽  
Vol 42 (10) ◽  
pp. 1683-1691 ◽  
Author(s):  
Y. Kumazaki ◽  
T. Akagi ◽  
T. Yanou ◽  
D. Suga ◽  
Y. Hishikawa ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Proton Beam ◽  
Mean Excitation Energy ◽  
The Mean
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