2D range modulator for high-precision water calorimetry in scanned carbon-ion beams.

Ionization chamber-based dosimetry for carbon-ion beams still shows a significantly higher standard uncertainty than high-energy photon dosimetry. This is mainly caused by the high standard uncertainty of the correction factor for beam quality [Formula: see text]. Due to a lack of experimental data, the given values for [Formula: see text] are based on theoretical calculations.

Experimental verification of a non-invasive method to monitor the lateral pencil beam position in an anthropomorphic phantom for carbon-ion radiotherapy.

The dose conformation and the sparing of neighboring critical healthy structures are improved in carbon-ion beam radiotherapy in comparison to conventional photon radiotherapy. Inter and intrafractional plan adaptation strategies may preclude the quality assurance (QA) of the actually applied treatment plan before the treatment starts. Therefore, independent measurements of the positions of scanned pencil C ion beams are of interest in order to monitor the beam application during the treatment and the beam in the isocenter.

Investigation of single carbon ion fragmentation in water and PMMA for hadron therapy.

Carbon ion radiotherapy is an attractive alternative to conventional radiotherapy, especially in case of deep-seated and radio-resistant tumors. As a consequence of inelastic nuclear reactions between primary particles and patient's tissues, the primary carbon ions may undergo nuclear fragmentation. The resulting decrease of primary ions and production of secondary fragments have to be carefully considered for accurate dose calculations in the treatment planning systems.

Theoretical and experimental comparison of proton and helium-beam radiography using silicon pixel detectors.

Ion-beam radiography (iRad) could potentially improve the quality control of ion-beam therapy. The main advantage of iRad is the possibility to directly measure the integrated stopping power. Until now there is no clinical implementation of iRad.

Analytical probabilistic modeling of RBE-weighted dose for ion therapy.

Particle therapy is especially prone to uncertainties. This issue is usually addressed with uncertainty quantification and minimization techniques based on scenario sampling. For proton therapy, however, it was recently shown that it is also possible to use closed-form computations based on analytical probabilistic modeling (APM) for this purpose.

Investigation of mixed ion fields in the forward direction for 220.5 MeV/u helium ion beams: comparison between water and PMMA targets.

Currently there is a rising interest in helium ion beams for radiotherapy. For benchmarking of the physical beam models used in treatment planning, there is a need for experimental data on the composition and spatial distribution of mixed ion fields. Of particular interest are the attenuation of the primary helium ion fluence and the build-up of secondary hydrogen ions due to nuclear interactions.

Coverage-based constraints for IMRT optimization.

Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning.

Radiation dosimetry in magnetic fields with Farmer-type ionization chambers: determination of magnetic field correction factors for different magnetic field strengths and field orientations.

The aim of this work was to determine magnetic field correction factors that are needed for dosimetry in hybrid devices for MR-guided radiotherapy for Farmer-type ionization chambers for different magnetic field strengths and field orientations. The response of six custom-built Farmer-type chambers irradiated at a 6 MV linac was measured in a water tank positioned in a magnet with magnetic field strengths between 0.0 T and 1.

Dedicated high dose rate Ir brachytherapy radiation fields for in vitro cell exposures at variable source-target cell distances: killing of mammalian cells depends on temporal dose rate fluctuation.

Afterloading brachytherapy is conducted by the stepwise movement of a radioactive source through surgically implanted applicator tubes where at predefined dwell positions calculated dwell times optimize spatial dose delivery with respect to a planned dose level. The temporal exposure pattern exhibits drastic fluctuations in dose rate at a given coordinate and within a single treatment session because of the discontinuous and repeated source movement into the target volume. This could potentially affect biological response.