The dose kernels of pencil and differential pencil photon beams with the spectrum of treatment machines with a 60Co source in water and their analytical approximation

Климанов, В. А.; Moiseev, A. N.; Колыванова, М. А.; Romodanov, V. L.; Chernyaev, A. P.

doi:10.3103/s0027134916040111

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…For this, a combination of the random search method and the nonlinear regression method was used, which was described in more detail in [31]. The results of approximation of the PB photon dose kernel for the bremsstrahlung spectrum with a maximum energy of 6.0 MeV and the spectrum of the ROKUS therapeutic apparatus charged with the Co-60 radionuclide were published in [30,32,33]. Therefore, we dwell here on the results of approximation of the PB dose kernel for the bremsstrahlung spectrum with maximum energy of 18 MeV, the form of which was taken from [34].…”

Section: Results and Discussioinmentioning

confidence: 99%

Spatial Distributions of the Dose Created Phantom Pencil Beam of Mono-Energy and Bremsstrahlung Photons in a Water with Energies from 0.25 to 20 MeV

Klimanov¹,

Kolyvanova²,

Moiseev³

2022

MEDICAL RADIOLOGY AND RADIATION SAFETY

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Purpose: Critical analysis of existing and obtaining more accurate data on the spatial dose distributions created in the water phantom by pencil beams (PB) of monoenergetic and bremsstrahlung photons with energies from 0.25 to 20.0 MeV, and approximation of these distributions for the purpose of calculating doses in radiation therapy. Material and Methods: Using the Monte Carlo method, the EGSnrc program and the MATLAB mathematical package, these distributions were calculated for monoenergetic photons in the energy range from 0.25 to 19.75 MeV in increments of 0.5 MeV, for bremsstrahlung photons with a maximum energy of 4.0, 6.0, 10.0, 15.0, 18.0 MeV and for the gamma-radiation spectrum of the therapeutic apparatus ROCUS. The calculation results are converted into the so-called dose kernel of photon pencil beam. The obtained dose kernel values are compared with previously published data and the observed discrepancies are discussed. Depths in water were studied from 1.0 to 40 cm in increments of 0,5 cm and along the radius from 0.02 to 46.0 cm with an uneven grid. For bremsstrahlung and photons with the spectrum of the Rocus apparatus, the possibility of approximating dose kernel values using approximation formulas convenient for calculating doses in radiation therapy has been investigated. Results: On the basis of the results obtained, a new version of the library of dose kernels of a pencil photon beam for water was created, which differs from previous versions by the use for calculating a better description and modeling of the physical processes of the interaction of photons and charged particles with matter, more adequate data on the interaction cross sections and significantly lower values of statistical uncertainties of the results. For bremsstrahlung and photons with the spectrum of the Rocus apparatus, a mathematical model of dose kernels of a pencil beam is proposed, which includes decomposition of the dose kernels into components of the primary and scattered doses, approximation formulas and empirical coefficients convenient for integration. The values of empirical coefficients are determined by fitting to the results of the calculation of dose kernels using a combination of the random search method and the nonlinear regression method. Conclusion: The results obtained in this work will improve the algorithms and increase the accuracy of dose calculation when planning remote therapy with photon beams.

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Section: Results and Discussioinmentioning

confidence: 99%

Spatial Distributions of the Dose Created Phantom Pencil Beam of Mono-Energy and Bremsstrahlung Photons in a Water with Energies from 0.25 to 20 MeV

Klimanov¹,

Kolyvanova²,

Moiseev³

2022

MEDICAL RADIOLOGY AND RADIATION SAFETY

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“…The coefficients were found by fitting to the Monte Carlo calculation results. The fitting method described by the authors in [5] was a combination of the random search method and the nonlinear regression method.…”

Section: Physbiosymp17mentioning

confidence: 99%

Determination of Small Beam Axial Dose Distribution in Water Based on the Mathematical Model of Pencil Beam Kernels

Колыванова¹,

Климанов²,

Moiseev³

2018

KEn

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An analytical model of the dose kernel of pencil beam for photon with the Bremsstrahlung spectrum with maximum energy 6 MV was created in this work, which makes it possible to determine the primary and scattered components of the absorbed dose in water phantom with an acceptable error for practice. Using this model a simply method of dosimetry of small circular cross section 6 MV photon beam was proposed. It combines the absolute measurement of the absorbed dose in the water at the reference point for reference geometry with the calculation of the deep dose distribution by simple analytical formulas for circular beams with an arbitrary radius of the cross section.

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An Analytical Model for Dosimetry of Nonstandard Photon Beams with Small, Round Cross Sections

Климанов

Колыванова

Moiseev³

et al. 2018

Biomed Eng

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The dose kernels of pencil and differential pencil photon beams with the spectrum of treatment machines with a 60Co source in water and their analytical approximation

Cited by 3 publications

References 17 publications

Spatial Distributions of the Dose Created Phantom Pencil Beam of Mono-Energy and Bremsstrahlung Photons in a Water with Energies from 0.25 to 20 MeV

Spatial Distributions of the Dose Created Phantom Pencil Beam of Mono-Energy and Bremsstrahlung Photons in a Water with Energies from 0.25 to 20 MeV

Determination of Small Beam Axial Dose Distribution in Water Based on the Mathematical Model of Pencil Beam Kernels

An Analytical Model for Dosimetry of Nonstandard Photon Beams with Small, Round Cross Sections

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