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Title: Geant4 simulation for a study of a possible use of carbon ions pencil beam for the treatment of ocular melanomas with the active scanning system at CNAO Centre

Conference ·
OSTI ID:22531249
 [1];  [2]; ; ;  [1];  [3]
  1. University of Pavia-Department of Physics, via Bassi 6, 27100 Pavia (Italy)
  2. Division of Radiation Research, Loma Linda University, Loma Linda, CA 92354 (United States)
  3. Medical Physics Unit, Centro Nazionale di Adroterapia Oncologica - CNAO Foundation, Strada Campeggi 53, 27100 Pavia (Italy)

The aim of this work is to validate the Geant4 application reproducing the CNAO (National Centre for Oncological Hadrontherapy) beamline and to study of a possible use of carbon ion pencil beams for the treatment of ocular melanomas at the CNAO Centre. The promising aspect of carbon ions radiotherapy for the treatment of this disease lies in its superior relative radiobiological effectiveness (RBE). The Monte Carlo Geant4 toolkit is used to simulate the complete CNAO extraction beamline, with the active and passive components along it. A human eye modeled detector, including a realistic target tumor volume, is used as target. Cross check with previous studies at CNAO using protons allows comparisons on possible benefits on using such a technique with respect to proton beams. Before the eye-detector irradiation a validation of the Geant4 simulation with CNAO experimental data is carried out with both carbon ions and protons. Important beam parameters such as the transverse FWHM and scanned radiation field 's uniformity are tested within the simulation and compared with experimental measurements at CNAO Centre. The physical processes involved in secondary particles generation by carbon ions and protons in the eye-detector are reproduced to take into account the additional dose to the primary beam given to irradiated eye's tissues. A study of beam shaping is carried out to produce a uniform 3D dose distribution (shaped on the tumor) by the use of a spread out Bragg peak. The eye-detector is then irradiated through a two dimensional transverse beam scan at different depths. In the use case the eye-detector is rotated of an angle of 40 deg. in the vertical direction, in order to mis-align the tumor from healthy tissues in front of it. The treatment uniformity on the tumor in the eye-detector is tested. For a more quantitative description of the deposited dose in the eye-detector and for the evaluation of the ratio between the dose deposited in the tumor and the other eye components, proton and carbon DVHs (Dose Volume Histograms) are compared. A high statistics simulated sample is used to minimize statistical errors. In the simulation a new particle generation method is developed in order to reproduce the experimental treatment plan by importing the DICOM RT-PLAN file, which contains all the information on the irradiation geometries and sequences (treatment plan parameters). Conclusions Even further validations must be done, the good results so far obtained by this work point out and confirm the possibility of using carbon ions delivered with active scanning beams to treat the ocular melanoma.

Research Organization:
Institute of Electrical and Electronics Engineers - IEEE, 3 Park Avenue, 17th Floor, New York, N.Y. 10016-5997 (United States)
OSTI ID:
22531249
Report Number(s):
ANIMMA-2015-IO-195; TRN: US16V0460102190
Resource Relation:
Conference: ANIMMA 2015: 4. International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, Lisboa (Portugal), 20-24 Apr 2015; Other Information: Country of input: France
Country of Publication:
United States
Language:
English