skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A pencil beam algorithm for helium ion beam therapy

Abstract

Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developedmore » calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient for clinical practice. Although only data for helium beams was presented, the performance of the pencil beam algorithm for proton beams was comparable. Conclusions: The pencil beam algorithm developed for helium ions presents a suitable tool for dose calculations. Its calculation speed was evaluated to be similar to other published pencil beam algorithms. The flexible design allows easy customization of measured depth-dose distributions and use of varying beam profiles, thus making it a promising candidate for integration into future treatment planning systems. Current work in progress deals with RBE effects of helium ions to complete the model.« less

Authors:
; ; ; ;  [1];  [2];  [2];  [3];  [3];  [3];  [2]
  1. Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna (Austria)
  2. (Austria) and Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, 1090 Vienna (Austria)
  3. (Austria)
Publication Date:
OSTI Identifier:
22099078
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 39; Journal Issue: 11; Other Information: (c) 2012 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; ALGORITHMS; BEAM PROFILES; BRAGG CURVE; COMPUTER CODES; COMPUTERIZED SIMULATION; DEPTH DOSE DISTRIBUTIONS; HELIUM IONS; ION BEAMS; MEV RANGE 100-1000; MONTE CARLO METHOD; PHANTOMS; PROTON BEAMS; RADIATION DOSES; RADIOTHERAPY; SKELETON

Citation Formats

Fuchs, Hermann, Stroebele, Julia, Schreiner, Thomas, Hirtl, Albert, Georg, Dietmar, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, PEG MedAustron, 2700 Wiener Neustadt, Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna, and Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna. A pencil beam algorithm for helium ion beam therapy. United States: N. p., 2012. Web. doi:10.1118/1.4757578.
Fuchs, Hermann, Stroebele, Julia, Schreiner, Thomas, Hirtl, Albert, Georg, Dietmar, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, PEG MedAustron, 2700 Wiener Neustadt, Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna, & Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna. A pencil beam algorithm for helium ion beam therapy. United States. doi:10.1118/1.4757578.
Fuchs, Hermann, Stroebele, Julia, Schreiner, Thomas, Hirtl, Albert, Georg, Dietmar, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna, Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, PEG MedAustron, 2700 Wiener Neustadt, Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna, Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna, and Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna. Thu . "A pencil beam algorithm for helium ion beam therapy". United States. doi:10.1118/1.4757578.
@article{osti_22099078,
title = {A pencil beam algorithm for helium ion beam therapy},
author = {Fuchs, Hermann and Stroebele, Julia and Schreiner, Thomas and Hirtl, Albert and Georg, Dietmar and Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna and Department of Radiation Oncology, Medical University of Vienna/AKH Vienna and PEG MedAustron, 2700 Wiener Neustadt and Department of Nuclear Medicine, Medical University of Vienna, 1090 Vienna and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, 1090 Vienna and Department of Radiation Oncology, Medical University of Vienna/AKH Vienna, 1090 Vienna},
abstractNote = {Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient for clinical practice. Although only data for helium beams was presented, the performance of the pencil beam algorithm for proton beams was comparable. Conclusions: The pencil beam algorithm developed for helium ions presents a suitable tool for dose calculations. Its calculation speed was evaluated to be similar to other published pencil beam algorithms. The flexible design allows easy customization of measured depth-dose distributions and use of varying beam profiles, thus making it a promising candidate for integration into future treatment planning systems. Current work in progress deals with RBE effects of helium ions to complete the model.},
doi = {10.1118/1.4757578},
journal = {Medical Physics},
issn = {0094-2405},
number = 11,
volume = 39,
place = {United States},
year = {2012},
month = {11}
}