guest ::
| Home > Publications database > Monte Carlo simulation for proton dosimetry in magnetic fields: Fano test and magnetic field correction factors kBfor Farmer-type ionization chambers. |
| Home > Publications database > Monte Carlo simulation for proton dosimetry in magnetic fields: Fano test and magnetic field correction factors kBfor Farmer-type ionization chambers. |
| Journal Article | DKFZ-2023-01641 |
; ; ; ; ;
2023
IOP Publ.
Bristol
This record in other databases: 
Please use a persistent id in citations: doi:10.1088/1361-6560/acefa1
Abstract: In this contribution we present a special Fano test for charged particles in presence of magnetic fields in the MC code TOPAS, as well as the determination of magnetic field correction factors kBfor Farmer-type ionization chambers using proton beams.

Approach: Customized C++ extensions for TOPAS were implemented to model the special Fano tests in presence of magnetic fields for electrons and protons. The Geant4-specific transport parameters,DRoverRandfinalRange, were investigated to optimize passing rate and computation time. The kBwas determined for the Farmer-type PTW 30013 ionization chamber, and 5 custom built ionization chambers with same geometry but varying inner radius, testing magnetic flux density ranging from 0 to 1.0 T and two proton beam energies of 157.43 and 221.05 MeV.

Main results: Using the investigated parameters, TOPAS passed the Fano test within 0.39±0.15% and 0.82±0.42%, respectively for electrons and protons. The chamber response (kBMQ) gives a maximum at different magnetic flux densities depending of the chamber size, 1.0043 at 1.0 T for the smallest chamber and 1.0051 at 0.2 T for the largest chamber. The local dose difference cBremained ≤ 0.1% for both tested energies. The magnetic field correction factor kB, for the chamber PTW 30013, varied from 0.9946 to 1.0036 for both tested energy.

Significance: The developed extension for the special Fano test in TOPAS MC code with the adjusted transport parameters, can accurately transport electron and proton particles in magnetic field. This makes TOPAS a valuable tool for the determination of kB. The ionization chambers we tested showed that kBremains small (<0.7%). To the best of our knowledge, this is the first calculations of kBfor proton beams. This work represents a significant step forward in the development of MRgPT and protocols for proton dosimetry in presence of magnetic field.
.
Keyword(s): MR-guided proton therapy ; TOPAS ; dosimetry ; magnetic field ; magnetic field correction factor
; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection
|
The record appears in these collections: |
