TY - JOUR
T1 - Antiproton radiotherapy
AU - Bassler, Niels
AU - Alsner, Jan
AU - Beyer, Gerd
AU - DeMarco, John J.
AU - Doser, Michael
AU - Hajdukovic, Dragan
AU - Hartley, Oliver
AU - Iwamoto, Keisuke S.
AU - Jäkel, Oliver
AU - Knudsen, Helge V.
AU - Kovacevic, Sandra
AU - Møller, Søren Pape
AU - Overgaard, Jens
AU - Petersen, Jørgen B.
AU - Solberg, Timothy D.
AU - Sørensen, Brita S.
AU - Vranjes, Sanja
AU - Wouters, Bradly G.
AU - Holzscheiter, Michael H.
N1 - Funding Information:
The Danish Cancer Society and the ICE Center under the Danish Natural Science Research Council partially supported this project with a grant. We very much appreciate the diligent efforts by the AD operations team to deliver the antiproton beam at CERN and to develop the new extraction scheme to provide the 126 MeV beam energy.
PY - 2008/1
Y1 - 2008/1
N2 - Antiprotons are interesting as a possible future modality in radiation therapy for the following reasons: When fast antiprotons penetrate matter, protons and antiprotons have near identical stopping powers and exhibit equal radiobiology well before the Bragg-peak. But when the antiprotons come to rest at the Bragg-peak, they annihilate, releasing almost 2 GeV per antiproton-proton annihilation. Most of this energy is carried away by energetic pions, but the Bragg-peak of the antiprotons is still locally augmented with ∼20-30 MeV per antiproton. Apart from the gain in physical dose, an increased relative biological effect also has been observed, which can be explained by the fact that some of the secondary particles from the antiproton annihilation exhibit high-LET properties. Finally, the weakly interacting energetic pions, which are leaving the target volume, may provide a real time feedback on the exact location of the annihilation peak. We have performed dosimetry experiments and investigated the radiobiological properties using the antiproton beam available at CERN, Geneva. Dosimetry experiments were carried out with ionization chambers, alanine pellets and radiochromic film. Radiobiological experiments were done with V79 WNRE Chinese hamster cells. The radiobiological experiments were repeated with protons and carbon ions at TRIUMF and GSI, respectively, for comparison. Several Monte Carlo particle transport codes were investigated and compared with our experimental data obtained at CERN. The code that matched our data best was used to generate a set of depth dose data at several energies, including secondary particle-energy spectra. This can be used as base data for a treatment planning software such as TRiP. Our findings from the CERN experiments indicate that the biological effect of antiprotons in the plateau region may be reduced by a factor of 4 for the same biological target dose in a spread-out Bragg-peak, when comparing with protons. The extension of TRiP to handle antiproton beams is currently in progress. This will enable us to perform planning studies, where the potential clinical consequences can be examined, and compared to those of other beam modalities such as protons, carbon ions, or IMRT photons.
AB - Antiprotons are interesting as a possible future modality in radiation therapy for the following reasons: When fast antiprotons penetrate matter, protons and antiprotons have near identical stopping powers and exhibit equal radiobiology well before the Bragg-peak. But when the antiprotons come to rest at the Bragg-peak, they annihilate, releasing almost 2 GeV per antiproton-proton annihilation. Most of this energy is carried away by energetic pions, but the Bragg-peak of the antiprotons is still locally augmented with ∼20-30 MeV per antiproton. Apart from the gain in physical dose, an increased relative biological effect also has been observed, which can be explained by the fact that some of the secondary particles from the antiproton annihilation exhibit high-LET properties. Finally, the weakly interacting energetic pions, which are leaving the target volume, may provide a real time feedback on the exact location of the annihilation peak. We have performed dosimetry experiments and investigated the radiobiological properties using the antiproton beam available at CERN, Geneva. Dosimetry experiments were carried out with ionization chambers, alanine pellets and radiochromic film. Radiobiological experiments were done with V79 WNRE Chinese hamster cells. The radiobiological experiments were repeated with protons and carbon ions at TRIUMF and GSI, respectively, for comparison. Several Monte Carlo particle transport codes were investigated and compared with our experimental data obtained at CERN. The code that matched our data best was used to generate a set of depth dose data at several energies, including secondary particle-energy spectra. This can be used as base data for a treatment planning software such as TRiP. Our findings from the CERN experiments indicate that the biological effect of antiprotons in the plateau region may be reduced by a factor of 4 for the same biological target dose in a spread-out Bragg-peak, when comparing with protons. The extension of TRiP to handle antiproton beams is currently in progress. This will enable us to perform planning studies, where the potential clinical consequences can be examined, and compared to those of other beam modalities such as protons, carbon ions, or IMRT photons.
KW - Antiproton
KW - Particle irradiation
KW - RBE
UR - http://www.scopus.com/inward/record.url?scp=38349091677&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=38349091677&partnerID=8YFLogxK
U2 - 10.1016/j.radonc.2007.11.028
DO - 10.1016/j.radonc.2007.11.028
M3 - Article
C2 - 18158194
AN - SCOPUS:38349091677
SN - 0167-8140
VL - 86
SP - 14
EP - 19
JO - Radiotherapy and Oncology
JF - Radiotherapy and Oncology
IS - 1
ER -