Nowadays, the irradiation methodology in proton therapy is switching from the use of passively scattered beams to active pencil beams due to the possibility of more conformal dose distributions. The dose rates of active pencil beams are much higher than those of passive beams. The purpose of this study was to investigate whether there is any difference in the biological effectiveness of these passive and active irradiation modes. The beam qualities of double scattering and pencil beam scanning were measured dosimetrically and simulated using the Monte Carlo code. Using the medulloblastoma cell line DAOY, we performed an in vitro comparison of the two modes in two positions along the dose-deposition curve plateau and inside the Bragg peak. We followed the clonogenic cell survival, apoptosis, micronuclei, and γH2AX assays as biological endpoints. The Monte Carlo simulations did not reveal any difference between the beam qualities of the two modes. Furthermore, we did not observe any statistically significant difference between the two modes in the in vitro comparison of any of the examined biological endpoints. Our results do not show any biologically relevant differences related to the different dose rates of passive and active proton beams.
- MeSH
- apoptóza účinky záření MeSH
- histony metabolismus MeSH
- lidé MeSH
- lineární přenos energie MeSH
- metoda Monte Carlo MeSH
- mikrojaderné testy MeSH
- nádorové buněčné linie MeSH
- neutrony MeSH
- počítačová simulace MeSH
- protonová terapie * MeSH
- viabilita buněk účinky záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Neutron detection using nuclear emulsions can offer an alternative in personal dosimetry. The production of emulsions and their quality have to be well controlled with respect to their application in dosimetry. Nuclear emulsions consist mainly of gelatin and silver halide. Gelatin contains a significant amount of hydrogen, which can be used for fast neutron detection. The addition of B-10 in the emulsion is convenient for thermal neutron detection. In this paper, standard nuclear emulsions BR-2 and nuclear emulsions BR-2 enriched with boron produced at the Slavich Company, Russia, were applied for evaluation of fast and thermal neutron fluences. The results were obtained by calculation from the presumed emulsion composition without prior calibration. Evidence that nuclear emulsions used in the experiment are suitable for neutron dosimetry is provided.
- MeSH
- bor chemie MeSH
- bromidy chemie MeSH
- emulze * MeSH
- fantomy radiodiagnostické MeSH
- helium analýza MeSH
- kalibrace MeSH
- lithium analýza MeSH
- neutrony * MeSH
- počítačové zpracování obrazu MeSH
- radiometrie přístrojové vybavení metody MeSH
- rychlé neutrony * MeSH
- sloučeniny stříbra chemie MeSH
- vodík chemie MeSH
- želatina chemie MeSH
- Publikační typ
- časopisecké články MeSH
A comparison between breast cancer cell line MCF7 and human adipose-derived stem cells (ADSC) after irradiation by the same doses of megavoltage X-rays was performed. The cell growth, the induction of apoptosis and the expression of selected genes were analyzed. Irradiated MCF7 related to its control sample grows slower than ADSC and it undergoes apoptosis in much higher levels than ADSC. This was confirmed by real-time polymerase chain reaction as well, where the expression of apoptotic genes was found to be considerably higher for MCF7 than for ADSC. From the results of this project, it could be stated that MCF7 is more radiosensitive than ADSC.
In recent years, there is an increased interest in using scanning modes in proton therapy, due to the more conformal dose distributions, thanks to the spot-weighted dose delivery. The dose rate in each spot is however much higher than the dose rate when using passive irradiation modes, which could affect the cell response. The purpose of this work was to investigate how the relative biological effectiveness changes along the spread-out Bragg peak created by protons delivered by the pencil beam scanning mode. Cell survival and micronuclei formation were investigated in four positions along the spread-out Bragg peak for various doses. Monte Carlo simulations were used to estimate the dose-averaged linear energy transfer values in the irradiation positions. The cell survival was found to decrease the deeper the sample was placed in the spread-out Bragg peak, which corresponds to the higher linear energy transfer values found using Monte Carlo simulations. The micronuclei frequencies indicate more complex cell injuries at that distal position compared to the proximal part of the spread-out Bragg peak. The relative biological effectiveness determined in this study varies significantly and systematically from 1.1, which is recommended value by the International Commission on Radiation Units, in all the studied positions. In the distal position of spread-out Bragg peak the relative biological effectiveness values were found to be 2.05 ± 0.44, 1.85 ± 0.42, 1.53 ± 0.38 for survival levels 90, 50 and 10%, respectively.
- MeSH
- lidé MeSH
- lineární přenos energie MeSH
- mikrojaderné testy MeSH
- novorozenec MeSH
- počítačová simulace MeSH
- protony * MeSH
- radiometrie MeSH
- relativní biologická účinnost * MeSH
- viabilita buněk účinky záření MeSH
- vztah dávky záření a odpovědi MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
