TY - JOUR
T1 - Design and development of a new micro-beam treatment planning system
T2 - Effectiveness of algorithms of optimization and dose calculations and potential of micro-beam treatment
AU - Tachibana, Hidenobu
AU - Kojima, Hiroyuki
AU - Yusa, Noritaka
AU - Miyajima, Satoshi
AU - Tsuda, Akihisa
AU - Yamashita, Takashi
N1 - Funding Information:
A new X-ray treatment system commissioned by the New Energy and Industrial Technology Development Organization (NEDO) was developed by The Cancer Institute of The Japanese Foundation of Cancer Research, Hokkaido University, and The University of Tokyo in collaboration with Accuthera Inc. The treatment system consisted of an x-band linac with a robotic arm (Fig. 1), a real-time tracking system using X-ray fluoroscopy, and a treatment planning system. The system generates an array of 4pi X-ray micro-beams of approximate diameter 1 mm. The treatment concept was based on multiple micro-beam irradiations of a small tumor of less than 1 cm3. Thus, the treatment system was designed to deliver an array of micro-beams that generated multiple tiny high-dose irradiation fields that were concentrated specifically in the tumor, with sparing of the surrounding tissues at risk. In the planning system, optimal algorithms required for automatically determining the direction and intensity of each of
Funding Information:
Acknowledgments This study was supported by New Energy and Industrial Development Organization, Japan (NEDO).
PY - 2012/7
Y1 - 2012/7
N2 - A new treatment planning system (TPS) was designed and developed for a new treatment system, which consisted of a micro-beam-enabled linac with robotics and a real-time tracking system. We also evaluated the effectiveness of the implemented algorithms of optimization and dose calculations in the TPS for the new treatment system. In the TPS, the optimization procedure consisted of the pseudo Beam's-Eye-View method for finding the optimized beam directions and the steepest-descent method for determination of beam intensities. We used the superposition-/ convolution-based (SC-based) algorithm and Monte Carlo-based (MC-based) algorithm to calculate dose distributions using CT image data sets. In the SC-based algorithm, dose density scaling was applied for the calculation of inhomogeneous corrections. The MC-based algorithm was implemented with Geant4 toolkit and a phase-based approach using a network-parallel computing. From the evaluation of the TPS, the system can optimize the direction and intensity of individual beams. The accuracy of the dose calculated by the SC-based algorithm was less than 1 % on average with the calculation time of 15 s for one beam. However, the MC-based algorithm needed 72 min for one beam using the phase-based approach, even though the MC-based algorithm with the parallel computing could decrease multiple beam calculations and had 18.4 times faster calculation speed using the parallel computing. The SC-based algorithm could be practically acceptable for the dose calculation in terms of the accuracy and computation time. Additionally, we have found a dosimetric advantage of proton Bragg peak-like dose distribution in micro-beam treatment.
AB - A new treatment planning system (TPS) was designed and developed for a new treatment system, which consisted of a micro-beam-enabled linac with robotics and a real-time tracking system. We also evaluated the effectiveness of the implemented algorithms of optimization and dose calculations in the TPS for the new treatment system. In the TPS, the optimization procedure consisted of the pseudo Beam's-Eye-View method for finding the optimized beam directions and the steepest-descent method for determination of beam intensities. We used the superposition-/ convolution-based (SC-based) algorithm and Monte Carlo-based (MC-based) algorithm to calculate dose distributions using CT image data sets. In the SC-based algorithm, dose density scaling was applied for the calculation of inhomogeneous corrections. The MC-based algorithm was implemented with Geant4 toolkit and a phase-based approach using a network-parallel computing. From the evaluation of the TPS, the system can optimize the direction and intensity of individual beams. The accuracy of the dose calculated by the SC-based algorithm was less than 1 % on average with the calculation time of 15 s for one beam. However, the MC-based algorithm needed 72 min for one beam using the phase-based approach, even though the MC-based algorithm with the parallel computing could decrease multiple beam calculations and had 18.4 times faster calculation speed using the parallel computing. The SC-based algorithm could be practically acceptable for the dose calculation in terms of the accuracy and computation time. Additionally, we have found a dosimetric advantage of proton Bragg peak-like dose distribution in micro-beam treatment.
KW - Micro-beam
KW - Monte Carlo
KW - Pseudo Beam's Eye View
KW - Steepest descent
KW - Superposition/convolution
KW - Treatment planning system
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U2 - 10.1007/s12194-012-0153-6
DO - 10.1007/s12194-012-0153-6
M3 - Article
C2 - 22544809
AN - SCOPUS:84866427472
SN - 1865-0333
VL - 5
SP - 186
EP - 198
JO - Radiological Physics and Technology
JF - Radiological Physics and Technology
IS - 2
ER -