Lateral variations of radiobiological properties of therapeutic fields of H, He, C and O ions studied with Geant4 and microdosimetric kinetic model.

As known, in cancer therapy with ion beams the relative biological effectiveness (RBE) of ions changes in the course of their propagation in tissues. Such changes are caused not only by increasing the linear energy transfer (LET) of beam particles with the penetration depth towards the Bragg peak, but also by nuclear reactions induced by beam nuclei leading to the production of various secondary particles. Although the changes of RBE along the beam axis have been studied quite well, much less attention has been paid to the evolution of RBE in the transverse direction, perpendicular to the beam axis.

Distributions of deposited energy and ionization clusters around ion tracks studied with Geant4 toolkit.

The Geant4-based Monte Carlo model for Heavy-Ion Therapy (MCHIT) was extended to study the patterns of energy deposition at sub-micrometer distance from individual ion tracks. Dose distributions for low-energy (1)H, (4)He, (12)C and (16)O ions measured in several experiments are well described by the model in a broad range of radial distances, from 0.5 to 3000 nm.

Comparative study of dose distributions and cell survival fractions for 1H, 4He, 12C and 16O beams using Geant4 and Microdosimetric Kinetic model.

Depth and radial dose profiles for therapeutic (1)H, (4)He, (12)C and (16)O beams are calculated using the Geant4-based Monte Carlo model for Heavy-Ion Therapy (MCHIT). (4)He and (16)O ions are presented as alternative options to (1)H and (12)C broadly used for ion-beam cancer therapy. Biological dose profiles and survival fractions of cells are estimated using the modified Microdosimetric Kinetic model.

Nanolesions induced by heavy ions in human tissues: Experimental and theoretical studies.

The biological effects of energetic heavy ions are attracting increasing interest for their applications in cancer therapy and protection against space radiation. The cascade of events leading to cell death or late effects starts from stochastic energy deposition on the nanometer scale and the corresponding lesions in biological molecules, primarily DNA. We have developed experimental techniques to visualize DNA nanolesions induced by heavy ions.

PET monitoring of cancer therapy with 3He and 12C beams: a study with the GEANT4 toolkit.

We study the spatial distributions of beta(+)-activity produced by therapeutic beams of (3)He and (12)C ions in various tissue-like materials. The calculations were performed within a Monte Carlo model for heavy-ion therapy (MCHIT) based on the GEANT4 toolkit. The contributions from positron-emitting nuclei with T(1/2) > 10 s, namely (10,11)C, (13)N, (14,15)O, (17,18)F and (30)P, were calculated and compared with experimental data obtained during and after irradiation, where available.

Distributions of positron-emitting nuclei in proton and carbon-ion therapy studied with GEANT4.

Depth distributions of positron-emitting nuclei in PMMA phantoms are calculated within a Monte Carlo model for heavy-ion therapy (MCHIT) based on the GEANT4 toolkit (version 8.0). The calculated total production rates of (11)C, (10)C and (15)O nuclei are compared with experimental data and with corresponding results of the FLUKA and POSGEN codes.

Neutrons from fragmentation of light nuclei in tissue-like media: a study with the GEANT4 toolkit.

We study energy deposition by light nuclei in tissue-like media taking into account nuclear fragmentation reactions, in particular, production of secondary neutrons. The calculations are carried out within a Monte Carlo model for heavy-ion therapy (MCHIT) based on the GEANT4 toolkit. Experimental data on depth-dose distributions for 135-400 A MeV (12)C and (18)O beams are described very well without any adjustment of the model parameters.