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Title: Technical Note: Experimental carbon ion range verification in inhomogeneous phantoms using prompt gammas

Abstract

Purpose: The purpose of this study was to experimentally assess the possibility to monitor carbon ion range variations—due to tumor shift and/or elongation or shrinking—using prompt-gamma (PG) emission with inhomogeneous phantoms. Such a study is related to the development of PG monitoring techniques to be used in a carbon ion therapy context. Methods: A 95 MeV/u carbon ion beam was used to irradiate phantoms with a variable density along the ion path to mimic the presence of bone and lung in homogeneous humanlike tissue. PG profiles were obtained after a longitudinal scan of the phantoms. A setup comprising a narrow single-slit collimator and two detectors placed at 90° with respect to the beam axis was used. The time of flight technique was applied to allow the selection between PG and background events. Results: Using the positions at 50% entrance and 50% falloff of the PG profiles, a quantity called prompt-gamma profile length (PGPL) is defined. It is possible to observe shifts in the PGPL when there are absolute ion range shifts as small as 1–2 mm. Quantitatively, for an ion range shift of −1.33 ± 0.46 mm (insertion of a Teflon slab), a PGPL difference of −1.93 ± 0.58 mmmore » and −1.84 ± 1.27 mm is obtained using a BaF{sub 2} and a NaI(Tl) detector, respectively. In turn, when an ion range shift of 4.59 ± 0.42 mm (insertion of a lung-equivalent material slab) is considered, the difference is of 4.10 ± 0.54 and 4.39 ± 0.80 mm for the same detectors. Conclusions: Herein, experimental evidence of the usefulness of employing PG to monitor carbon ion range using inhomogeneous phantoms is presented. Considering the homogeneous phantom as reference, the results show that the information provided by the PG emission allows for detecting ion range shifts as small as 1–2 mm. When considering the expected PG emission from an energy slice in a carbon ion therapy scenario, the experimental setup would allow to retrieve the same PGPL as the high statistics of the full experimental dataset in 58% of the times. However, this success rate increases to 93% when using a better optimized setup by means of Monte Carlo simulations.« less

Authors:
; ; ; ; ; ;  [1];  [2];  [2];  [3];  [2];  [2];  [4]; ;  [5];  [2];  [2]
  1. IPNL, Université de Lyon, Lyon F-69003 |(France)
  2. (France)
  3. IPNL, Université de Lyon, Lyon F-69003 (France)
  4. (Belgium)
  5. CREATIS, Université de Lyon, Lyon F-69003 (France)
Publication Date:
OSTI Identifier:
22413550
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 42; Journal Issue: 5; Other Information: (c) 2015 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:
60 APPLIED LIFE SCIENCES; CARBON IONS; COMPUTERIZED SIMULATION; ION BEAMS; LUNGS; MONTE CARLO METHOD; NEOPLASMS; PHANTOMS; RADIOTHERAPY

Citation Formats

Pinto, M., Dauvergne, D., Dedes, G., Krimmer, J., Ray, C., Testa, E., E-mail: e.testa@ipnl.in2p3.fr, Testa, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, De Rydt, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, Leuven B-3001, Freud, N., Létang, J. M., Université Lyon 1, Villeurbanne F-69622, and CNRS UMR 5220, INSERM U1044, INSA-Lyon, Centre Léon Bérard, 69008 Lyon. Technical Note: Experimental carbon ion range verification in inhomogeneous phantoms using prompt gammas. United States: N. p., 2015. Web. doi:10.1118/1.4917225.
Pinto, M., Dauvergne, D., Dedes, G., Krimmer, J., Ray, C., Testa, E., E-mail: e.testa@ipnl.in2p3.fr, Testa, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, De Rydt, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, Leuven B-3001, Freud, N., Létang, J. M., Université Lyon 1, Villeurbanne F-69622, & CNRS UMR 5220, INSERM U1044, INSA-Lyon, Centre Léon Bérard, 69008 Lyon. Technical Note: Experimental carbon ion range verification in inhomogeneous phantoms using prompt gammas. United States. doi:10.1118/1.4917225.
Pinto, M., Dauvergne, D., Dedes, G., Krimmer, J., Ray, C., Testa, E., E-mail: e.testa@ipnl.in2p3.fr, Testa, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, De Rydt, M., Université Lyon 1, Villeurbanne F-69622, CNRS/IN2P3, UMR 5822, Villeurbanne F-69622, Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, Leuven B-3001, Freud, N., Létang, J. M., Université Lyon 1, Villeurbanne F-69622, and CNRS UMR 5220, INSERM U1044, INSA-Lyon, Centre Léon Bérard, 69008 Lyon. Fri . "Technical Note: Experimental carbon ion range verification in inhomogeneous phantoms using prompt gammas". United States. doi:10.1118/1.4917225.
@article{osti_22413550,
title = {Technical Note: Experimental carbon ion range verification in inhomogeneous phantoms using prompt gammas},
author = {Pinto, M. and Dauvergne, D. and Dedes, G. and Krimmer, J. and Ray, C. and Testa, E., E-mail: e.testa@ipnl.in2p3.fr and Testa, M. and Université Lyon 1, Villeurbanne F-69622 and CNRS/IN2P3, UMR 5822, Villeurbanne F-69622 and De Rydt, M. and Université Lyon 1, Villeurbanne F-69622 and CNRS/IN2P3, UMR 5822, Villeurbanne F-69622 and Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, Leuven B-3001 and Freud, N. and Létang, J. M. and Université Lyon 1, Villeurbanne F-69622 and CNRS UMR 5220, INSERM U1044, INSA-Lyon, Centre Léon Bérard, 69008 Lyon},
abstractNote = {Purpose: The purpose of this study was to experimentally assess the possibility to monitor carbon ion range variations—due to tumor shift and/or elongation or shrinking—using prompt-gamma (PG) emission with inhomogeneous phantoms. Such a study is related to the development of PG monitoring techniques to be used in a carbon ion therapy context. Methods: A 95 MeV/u carbon ion beam was used to irradiate phantoms with a variable density along the ion path to mimic the presence of bone and lung in homogeneous humanlike tissue. PG profiles were obtained after a longitudinal scan of the phantoms. A setup comprising a narrow single-slit collimator and two detectors placed at 90° with respect to the beam axis was used. The time of flight technique was applied to allow the selection between PG and background events. Results: Using the positions at 50% entrance and 50% falloff of the PG profiles, a quantity called prompt-gamma profile length (PGPL) is defined. It is possible to observe shifts in the PGPL when there are absolute ion range shifts as small as 1–2 mm. Quantitatively, for an ion range shift of −1.33 ± 0.46 mm (insertion of a Teflon slab), a PGPL difference of −1.93 ± 0.58 mm and −1.84 ± 1.27 mm is obtained using a BaF{sub 2} and a NaI(Tl) detector, respectively. In turn, when an ion range shift of 4.59 ± 0.42 mm (insertion of a lung-equivalent material slab) is considered, the difference is of 4.10 ± 0.54 and 4.39 ± 0.80 mm for the same detectors. Conclusions: Herein, experimental evidence of the usefulness of employing PG to monitor carbon ion range using inhomogeneous phantoms is presented. Considering the homogeneous phantom as reference, the results show that the information provided by the PG emission allows for detecting ion range shifts as small as 1–2 mm. When considering the expected PG emission from an energy slice in a carbon ion therapy scenario, the experimental setup would allow to retrieve the same PGPL as the high statistics of the full experimental dataset in 58% of the times. However, this success rate increases to 93% when using a better optimized setup by means of Monte Carlo simulations.},
doi = {10.1118/1.4917225},
journal = {Medical Physics},
issn = {0094-2405},
number = 5,
volume = 42,
place = {United States},
year = {2015},
month = {5}
}