Mapping of RBE-Weighted Doses Between HIMAC- and LEM-Based Treatment Planning Systems for Carbon Ion Therapy

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2012.01.038· OSTI ID:22149612

Steinstraeter, Olaf ^[1]; Gruen, Rebecca ^[1]; Scholz, Uwe ^[1]; Friedrich, Thomas ^[1]; Durante, Marco ^[1]; Scholz, Michael ^[1]

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1. Abteilung Biophysik, GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

Purpose: A method was developed to convert clinically prescribed RBE (Relative Biological Effectiveness)-weighted doses from the approach used at the Heavy-Ion Medical Accelerator (HIMAC) at the National Institute of Radiological Science, Chiba, Japan, to the LEM (Local Effect Model)-based TReatment planning for Particles (TRiP98) approach used in the pilot project at the GSI Helmholtzzentrum, Darmstadt, and the Heidelberg Ion-Beam Therapy Center (HIT). Methods and Materials: The proposed conversion method is based on a simulation of the fixed spread-out Bragg peak (SOBP) depth dose profiles as used for the irradiation at HIMAC by LEM/TRiP98 and a recalculation of the resulting RBE-weighted dose distribution. We present data according to the clinical studies conducted at GSI in the past decade (LEM I), as well as data used in current studies (refined LEM version: LEM IV). Results: We found conversion factors (RBE-weighted dose LEM/RBE-weighted dose HIMAC) reaching from 0.4 to 2.0 for prescribed carbon ion doses from 1 to 60 Gy (RBE) for SOBP extensions ranging from 20 to 120 mm according to the HIMAC approach. A conversion factor of 1.0 was found for approximately 5 Gy (RBE). The conversion factor decreases with increasing prescribed dose. Slightly smaller values for the LEM IV-based data set compared with LEM I were found. A significant dependence of the conversion factor from the SOBP width could be observed in particular for LEM IV, whereas the depth dependence was found to be small. Conclusions: For the interpretation and comparison of clinical trials performed at HIMAC and GSI/HIT, it is of extreme importance to consider these conversion factors because according to the various methods to determine the RBE-weighted dose, similar dose values might not necessarily be related to similar clinical outcomes.

• OSTI ID: 22149612
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 84; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BRAGG CURVE
CARBON IONS
CLINICAL TRIALS
DEPTH DOSE DISTRIBUTIONS
HEAVY IONS
ION BEAMS
IRRADIATION
PLANNING
RADIATION DOSES
RADIOTHERAPY
SIMULATION