EGS4 Energy Deposition Kernels at Low Photon Energy including the Molecular Coherent Scattering Form Factor

Modrick, Joseph M.; Mackie, Thomas Rockwell; Thomadsen, Bruce R.

doi:10.1007/978-3-642-59758-9_189

Cited by 1 publication

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… The difference in percent is calculated using 100 × (( F pri ‐ μ en / μ )/ ( μ en / μ )), for this study, Alaei et al, 16 Mackie et al 25 and Modrick 27,29 was F pri|This Study , F pri|Alaei , F pri|Mackie and F pri | Modrick , respectively …”

Section: Resultsmentioning

confidence: 99%

“…25 The generated water energy deposition kernels in this study have been compared with kernels reported previously. Table 2 shows a comparison of the primary energy fraction (F pri ) for water from this and previous studies 16,25,27,29 and their comparison with the energy absorption to attenuation coefficient ratio data from the National Institute of Standards and Technology (NIST). 41 The primary energy fraction is defined as the ratio of deposited energy of charged particles produced by the primary photon to the total energy of the photon, hence its comparison to attenuation coefficient ratios.…”

Section: Water Energy Deposition Kernelsmentioning

confidence: 99%

“…Previous work in generating dose deposition kernels includes those of Boyer and Mok, Ahnesjo, Mackie, Alaei, Modrick, Maniegra‐Hing, and Huang 16,20,21,24‐29 . Boyer and Mok 24 used convolution calculations to analytically produce the kernels, using calculated attenuation coefficients and scattering cross sections.…”

Section: Introductionmentioning

confidence: 99%

“…23 Previous work in generating dose deposition kernels includes those of Boyer and Mok, Ahnesjo, Mackie, Alaei, Modrick, Maniegra-Hing, and Huang. 16,20,21,[24][25][26][27][28][29] Boyer and Mok 24 used convolution calculations to analytically produce the kernels, using calculated attenuation coefficients and scattering cross sections. In their approach, single-point interaction kernels were convolved with the photon fluence in order to obtain the primary, first, and multiple scattering components.…”

Section: Introductionmentioning

confidence: 99%

“…They modified simulation parameters of photon transport in Mackie's approach. 25 Modrick et al 27,29 developed an extension called lowenergy photon scattering (LSCAT) in EGS4 code (suitable for energy deposition kernel calculations below 100 keV) to calculate energy deposition kernels in a sphere. They separated the kernels into primary and scattering components and showed that the primary component made the main contribution to the depth dose.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Generation of material‐specific energy deposition kernels for kilovoltage x‐ray dose calculations

et al. 2021

View full text Add to dashboard Cite

Purpose Dose calculation of kilovoltage x rays used in Image‐Guided Radiotherapy has been investigated in recent years using various methods. Among these methods are model‐based ones that suffer from inaccuracies in high‐density materials and at interfaces when used in the kilovoltage energy range. The main reason for this is the use of water energy deposition kernels and simplifications employed such as density scaling in heterogeneous media. The purpose of this study was to produce and characterize material‐specific energy deposition kernels, which could be used for dose calculations in this energy range. These kernels will also have utility in dose calculations in superficial radiation therapy and orthovoltage beams utilized in small animal irradiators. Methods Water energy deposition kernels with various resolutions; and high‐resolution, material‐specific energy deposition kernels were generated in the energy range of 10–150 kVp, using the EGSnrc Monte Carlo toolkit. The generated energy deposition kernels were further characterized by calculating the effective depth of penetration, the effective radial distance, and the effective lateral distance. A simple benchmarking of the kernels against Monte Caro calculations has also been performed. Results There was good agreement with previously reported water kernels, as well as between kernels with different resolution. The evaluation of effective depth of penetration, and radial and laterals distances, defines the relationship between energy, material density, and the shape of the material‐specific kernels. The shape of these kernels becomes more forwardly scattered as the energy and material density are increased. The comparison of the dose calculated using the kernels with Monte Carlo provides acceptable results. Conclusions Water and material‐specific energy deposition kernels in the kilovoltage energy range have been generated, characterized, and compared to previous work. These kernels will have utility in dose calculations in this energy range once algorithms capable of employing them are fully developed.

show abstract