Biologically optimized helium ion plans: calculation approach and its in vitro validation

Treatment planning studies on the biological effect of raster-scanned helium ion beams should be performed, together with their experimental verification, before their clinical application at the Heidelberg Ion Beam Therapy Center (HIT). For this purpose, we introduce a novel calculation approach ba...

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Veröffentlicht in:Physics in medicine & biology 2016-06, Vol.61 (11), p.4283-4299
Hauptverfasser: Mairani, A, Dokic, I, Magro, G, Tessonnier, T, Kamp, F, Carlson, D J, Ciocca, M, Cerutti, F, Sala, P R, Ferrari, A, Böhlen, T T, Jäkel, O, Parodi, K, Debus, J, Abdollahi, A, Haberer, T
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Sprache:eng
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Zusammenfassung:Treatment planning studies on the biological effect of raster-scanned helium ion beams should be performed, together with their experimental verification, before their clinical application at the Heidelberg Ion Beam Therapy Center (HIT). For this purpose, we introduce a novel calculation approach based on integrating data-driven biological models in our Monte Carlo treatment planning (MCTP) tool. Dealing with a mixed radiation field, the biological effect of the primary 4He ion beams, of the secondary 3He and 4He (Z  =  2) fragments and of the produced protons, deuterons and tritons (Z  =  1) has to be taken into account. A spread-out Bragg peak (SOBP) in water, representative of a clinically-relevant scenario, has been biologically optimized with the MCTP and then delivered at HIT. Predictions of cell survival and RBE for a tumor cell line, characterized by (α/β)ph=5.4 Gy, have been successfully compared against measured clonogenic survival data. The mean absolute survival variation (μΔS) between model predictions and experimental data was 5.3%  ±  0.9%. A sensitivity study, i.e. quantifying the variation of the estimations for the studied plan as a function of the applied phenomenological modelling approach, has been performed. The feasibility of a simpler biological modelling based on dose-averaged LET (linear energy transfer) has been tested. Moreover, comparisons with biophysical models such as the local effect model (LEM) and the repair-misrepair-fixation (RMF) model were performed. μΔS values for the LEM and the RMF model were, respectively, 4.5%  ±  0.8% and 5.8%  ±  1.1%. The satisfactorily agreement found in this work for the studied SOBP, representative of clinically-relevant scenario, suggests that the introduced approach could be applied for an accurate estimation of the biological effect for helium ion radiotherapy.
ISSN:0031-9155
1361-6560
DOI:10.1088/0031-9155/61/11/4283