Monte Carlo calculation of beam quality correction factors in proton beams using FLUKA | Semantic Scholar (2024)

There is a need for updating the current recommendations, which assume a constant P of unity in carbon-ion beams, to recommendations that consider chamber-induced differences, as shown in the results.

Analysis of currently available data on beam quality correction factors, kQ, for ionization chambers in clinical proton beams and derive their current best estimates for the updated recommendations of the IAEA TRS-398 Code of Practice showed that except for the beam quality dependence of the water-to-air mass stopping power ratio and of the displacement correction factor, there is no remaining beam quality Dependency pQ.

The precise measurement of beam quality correction factors for mono-energy proton beams using the Monte Carlo technique is required in future studies.

The results indicate that PHITS can calculate the [Formula: see text] and [Formula: see text] with high precision and compare with that of a previous study, which was calculated using other Monte Carlo codes under similar conditions.

The k Q values determined in the present work have been compared with the values tabulated in TRS-398 and its forthcoming update and also with those obtained in previous water calorimetric measurements and Monte Carlo calculations and all results were found to agree within the combined uncertainties of the different data.

The detector showed a reduced dose-response for all measured energies and MF strengths, resulting in experimentally determined k B ⃗ , M , Q $k_{\vec{B},M,Q}$ values larger than unity.

The establishment of a primary standard calorimeter for the determination of absorbed dose in proton beams combined with the introduction of the associated calibration service following the IPEM recommendations will reduce the uncertainty and improve consistency in the dose delivered to patients.

KQ factors calculated in this work were found to agree within 1% or better with experimentally determined kQ factors provided in the literature, with only two exceptions with deviations of 1.4% and 2.4%.

The results of this work seem to indicate that the simulation of proton nuclear interactions should be included in the MC calculation of factors in proton beams, perturbation factors in Proton beams should not be neglected, and the detailed MC simulation of ionization chambers allows for an accurate and precise calculation of Factors in clinical protonbeam beams.

It is concluded that perturbation correction factors in proton beams—currently assumed to be equal to unity—are in fact significantly different from unity for some of the ionization chambers studied.

The perturbation factors p Q were shown to deviate from unity for the investigated chambers, contradicting the assumptions made in dosimetry protocols and the approximation of ionization chamber perturbations in proton beams by the respective water-to-air mass stopping power ratio shall be revised.

Whether the Monte Carlo codes penh, fluka, and geant4/topas are capable of calculating beam quality correction factors in proton beams is analyzed.

The results support the suggestion that the IAEA TRS-398 reference conditions for monoenergetic proton beams should be revised so that the effective point of measurement of cylindrical ionization chambers is taken into account when positioning the reference point of the chamber at the reference depth.

Ionization chamber perturbation factors are shown to be energy dependent and nuclear interactions must be taken into account for accurate calculation of the ionization chamber's response and need to be considered in dosimetry procedures.

The objectives of this study are to design a new Fano cavity test for proton MC and to implement the methodology in two MC codes: Geant4 and PENELOPE extended to protons (PENH).

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