Out-of-field dose studies with an anthropomorphic phantom: comparison of X-rays and particle therapy treatments

Background and purpose: Characterization of the out-of-field dose profile following irradiation of the target with a 3D treatment plan delivered with modern techniques.Methods: An anthropomorphic RANDO phantom was irradiated with a treatment plan designed for a simulated 5x2x5 cm3tumor volume located in the center of the head. The experiment was repeated withall most common radiation treatment types (photons, protons and carbon ions) and delivery techniques(Intensity Modulated Radiation Therapy, passive modulation and spot scanning). The measurementswere performed with active diamond detector and passive thermoluminescence (TLD) detectors to investigate the out-of-field dose both inside and outside the phantom.Results: The highest out-of-field dose values both on the surface and inside the phantom were measuredduring the treatment with 25 MV photons. In the proximity of the Planned Target Volume (PTV), the lowest lateral dose profile was observed for passively modulated protons mainly because of the presence ofthe collimator in combination with the chosen volume shape. In the far out-of-field region (above100 mm from the PTV), passively modulated ions were characterized by a less pronounced dose falloff in comparison with scanned beams. Overall, the treatment with scanned carbon ions delivered thelowest dose outside the target volume.Conclusions: For the selected PTV, the use of the collimator in proton therapy drastically reduced the dosedeposited by ions or photons nearby the tumor. Scanning modulation represents the optimal techniquefor achieving the highest dose reduction far-out-of-field

Test of weak and strong factorization in nucleus-nucleus collisions at several hundred MeV/nucleon

Projectile total and partial charge-changing cross sections have been measured for argon ions at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cross sections; measurements obtained for carbon, neon andsilicon beams at 290 and 400 MeV/nucleon and iron beam at 400 MeV/nucleon, in carbon, aluminum, copper, tin and lead targets have also been used for the test. Two different analysis methods were applied and both indicated that these properties are valid, without any significant difference between weak and strongfactorization. The factorization parameters have then been calculated and analyzed in order to find some systematic behavior useful for modeling purposes

Investigations of Single Event Effects With Heavy Ions of Energies up to 1.5 GeV/n

The ESA SEU-Monitor, a 2 Gbit DDR2 SDRAM and a 100 V n-channel power MOSFET have been irradiated at GSI with ions of energies from 80 to 1500 MeV/n. The measured SEE sensitivities are compared to low energy ( < 50 MeV /n ) data. The ESA SEU-Monitor and the DDR2 SDRAM showed only differences in the cross sections below the ionization threshold. Here the cross sections were lower for the high energy ions compared to the low energy ions. The power MOSFETs on the other hand showed a reduced safe operating area (SOA) for the high energy ions, although some experimental reasons other than the ion energy cannot be ruled out here

Addendum: Measurement of charged particle yields from PMMA irradiated by a 220 MeV/u 12^{12}C beam

In this paper we report the re-analysis of the data published in (Piersanti et al. 2014) documenting the charged secondary particles production induced by the interaction of a 220 MeV/u 12C ion beam impinging on a polymethyl methacrylate (PMMA) target, measured in 2012 at the GSI facility in Darmstadt (Germany). This re-analysis takes into account the inhomogeneous light response of the LYSO crystal in the experimental setup measured in a subsequent experiment (2014) performed in the Heidelberg Ion- Beam Therapy Center. A better description of the detector and re-calculation of the geometrical efficiencies have been implemented as well, based on an improved approach that accounts also for the energy dependence of the emission spectrum. The new analysis has small effect on the total secondary charged flux, but has an impact on the production yield and emission velocity distributions of the different particle species (protons, deuterons and tritons) at different angles with respect to the beam direction (60° and 90°). All these observables indeed depend on the particle identification algorithms and hence on the LYSO detector energy response. The results of the data re-analysis presented here are intended to supersede and replace the results published in (Piersanti et al. 2014)