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- Ambrozova, I., et al.
(author)
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Microdosimetry for a carbon ion beam using track-etched detectors
- 2015
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In: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 166:1-4, s. 247-252
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Journal article (peer-reviewed)abstract
- Track-etched detectors (TED) have been used as linear energy transfer (LET) spectrometers in heavy ion beams for many years. LET spectra and depth-dose distribution of a carbon ion beam were measured behind polymethylmethacrylate degraders at Heavy Ion Medical Accelerator in Chiba, Japan. The measurements were performed along monoenergetic beam with energy 290 MeV u-1 in different positions: (1) at beam extraction area, (2) at beginning, (3) maximum and (4) behind the Bragg peak region (0, 117, 147 and 151 mm of water-equivalent depth, respectively). The LET spectra inside and outside of the primary ion beam have been evaluated. TED record only heavy charged particles with LET above 8-10 keV μm-1, while electrons and ions with lower LET are not detected. The Geant4 simulation toolkit version 4.9.6.P01 has been used to estimate the contribution of non-detected particles to absorbed dose. Presented results demonstrate the applicability of TED for microdosimetry measurements in therapeutic carbon ion beams.
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| 2. |
- Pachnerova Brabcová, Katerina, 1978, et al.
(author)
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CONTRIBUTION OF INDIRECT EFFECTS TO CLUSTERED DAMAGE IN DNA IRRADIATED WITH PROTONS
- 2015
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In: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 166:1-4, s. 44-48
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Journal article (peer-reviewed)abstract
- Protons are the dominant particles both in galactic cosmic rays and in solar particle events and, furthermore, proton irradiation becomes increasingly used in tumour treatment. It is believed that complex DNA damage is the determining factor for the consequent cellular response to radiation. DNA plasmid pBR322 was irradiated at U120-M cyclotron with 30 MeV protons and treated with two Escherichia coli base excision repair enzymes. The yields of SSBs and DSBs were analysed using agarose gel electrophoresis. DNA has been irradiated in the presence of hydroxyl radical scavenger (coumarin-3-carboxylic acid) in order to distinguish between direct and indirect damage of the biological target. Pure scavenger solution was used as a probe for measurement of induced OH center dot radical yields. Experimental OH center dot radical yield kinetics was compared with predictions computed by two theoretical models-RADAMOL and Geant4-DNA. Both approaches use Geant4-DNA for description of physical stages of radiation action, and then each of them applies a distinct model for description of the pre-chemical and chemical stage.
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