Estimate of the Biological Dose in Hadrontherapy Using GATE

Abstract

For the evaluation of the biological effects, Monte Carlo toolkits were used to provide an RBE-weighted dose using databases of survival fraction coefficients predicted through biophysical models. Biophysics models, such as the mMKM and NanOx models, have previously been developed to estimate a biological dose. Using the mMKM model, we calculated the saturation corrected dose mean specific energy z1D* (Gy) and the dose at 10% D₁₀ for human salivary gland (HSG) cells using Monte Carlo Track Structure codes LPCHEM and Geant4-DNA, and compared these with data from the literature for monoenergetic ions. These two models were used to create databases of survival fraction coefficients for several ion types (hydrogen, carbon, helium and oxygen) and for energies ranging from 0.1 to 400 MeV/n. We calculated α values as a function of LET with the mMKM and the NanOx models, and compared these with the literature. In order to estimate the biological dose for SOBPs, these databases were used with a Monte Carlo toolkit. We considered GATE, an open-source software based on the GEANT4 Monte Carlo toolkit. We implemented a tool, the BioDoseActor, in GATE, using the mMKM and NanOx databases of cell survival predictions as input, to estimate, at a voxel scale, biological outcomes when treating a patient. We modeled the HIBMC 320 MeV/u carbon-ion beam line. We then tested the BioDoseActor for the estimation of biological dose, the relative biological effectiveness (RBE) and the cell survival fraction for the irradiation of the HSG cell line. We then tested the implementation for the prediction of cell survival fraction, RBE and biological dose for the HIBMC 320 MeV/u carbon-ion beamline. For the cell survival fraction, we obtained satisfying results. Concerning the prediction of the biological dose, a 10% relative difference between mMKM and NanOx was reported.

Keywords: GATE; Geant4-DNA; LPCHEM; Monte Carlo; NanOx; biological dose; mMKM.

Figure 4

Predictions of α values as a function of LET for the HSG cell line in response to irradiations with carbon, helium, hydrogen, and oxygen monoenergetic ions, for mMKM and NanOx models, using LPCHEM and Geant4-DNA MCTS codes. For carbon and helium ions, our results were compared to Chen et al. [30], Russo et al. [31] and to the PIDE database [26].

Figure 1

Algorithm of the BioDoseActor.

Figure 2

$z_{1D}^{*}$ values as a function of the kinetic energy of hydrogen, helium and carbon ions for HSG cells. Values from Inaniwa et al. were obtained from the track structure of the Kiefer–Chatterjee model [24].

Figure 3

D₁₀ values under aerobic conditions as a function of LET for helium and carbon beams for HSG cells. Geant4-DNA and LPCHEM were compared with the values from Inaniwa et al. [24] (using the track of the Kiefer–Chatterjee model) and the experimental data from Furusawa et al. [34].

Figure 5

Survival fractions of HSG cells as a function of the dose using the BioDoseActor with the NanOx model (red curve) and the mMKM model (green curve) and experimental data from Kagawa et al. [25] for five positions in the SOBP: 5 mm, 101 mm, 123 mm, 145 mm, and 149 mm of the HIBMC 320 MeV/u carbon-ion beam line.

Figure 6

Physical dose (light grey), biological dose, RBE and survival fractions provided by the BioDoseActor as a function of target depth: NanOx model (red curve), mMKM model (green curve) and experimental data from Kagawa et al. [25] (black curves and dots) for the HIBMC 320 MeV/u carbon-ion beam line.