Experimental Validation of Monte Carlo Simulation for the Leksell Gamma Knife Perfexion Using Gafchromic EBT3 Dosimetry Film and Diamond Detector T60019 PTW

Medjadj, T.; Ksenofontov, A. I.; Климанов, В. А.; Dalechina, Alexandra; Kirpichev, Yu. S.

doi:10.1134/s0020441221010292

Cited by 1 publication

(2 citation statements)

References 17 publications

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“…For small field dosimetry, it is crucial to determine the field output correction factor

k_{{Q}_{msr},\ {Q}_{clin}\ }^{{f}_{msr},\ {f}_{clin}}

to be able to correct the detector's reading and account for the abovementioned nonequilibrium conditions in machine‐specific reference f msr (msr) and clinical fields f clin (clin) with beam qualities Q msr and Q clin . Together with the field output factor (OF)

{{\Omega}}_{{Q}_{msr},\ {Q}_{clin}}^{{f}_{msr},{f}_{clin}}

determination, these were the focus of investigation performed by different groups 2–11 . OF and field output correction factor determination for different detectors can be performed by measurements or with Monte Carlo (MC) simulations.…”

Section: Introductionmentioning

confidence: 99%

“…Together with the field output factor (OF)

determination, these were the focus of investigation performed by different groups. 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 OF and field output correction factor determination for different detectors can be performed by measurements or with Monte Carlo (MC) simulations. In general, field output correction factors are a product of four different perturbations in the small field; ratios of water‐to‐detector‐medium stopping powers in the clinical and machine‐specific reference field, volume averaging, fluence, and of spectral perturbations in clinical and machine‐specific reference fields.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Determination of volume averaging correction factors using an elliptical absorbed dose model for Gamma Knife Perfexion

Šegedin,

Hršak,

Babić

et al. 2023

J Applied Clin Med Phys

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PurposeThe purpose of this study is to calculate volume averaging correction factors for detectors used in the dosimetry of Gamma Knife's narrow photon beams, and to determine the impact of volume averaging on the field output correction factor.MethodsSimulations of different Gamma Knife fields were done using elliptical dose model formalism with newly introduced fit functions. To determine volume averaging correction factors a calculation of the absorbed dose over the volume of the detector was performed. The elliptical dose model was tested with respect to absorbed dose distribution for different volumes and compared with the calculations of Leksell GammaPlan v.11.3.1.ResultsThe largest differences in absorbed dose calculated by the elliptical model and Leksell GammaPlan are 2.25%, 1.5%, and 0.6% for 16, 8, and 4 mm field sizes, respectively. Volume averaging correction factors were determined for six ionization chambers, five semiconductor detectors, a diamond, and two plastic scintillator detectors. In general, for all examined detectors the impact of volume averaging is more pronounced for smaller field sizes. All studied ionization chambers had a larger volume than other detectors, therefore the volume averaging correction factors for ionization chambers are larger for all investigated field sizes. Besides the fact that plastic scintillator detectors can be considered tissue‐equivalent, volume averaging correction factor should be applied.ConclusionVolume averaging correction factors for different detectors are determined and suitable detectors for dosimetry of Gamma Knife's narrow photon beams are recommended. It is shown that volume averaging has a dominant contribution to a field output correction factor.

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“…For small field dosimetry, it is crucial to determine the field output correction factor