Numerical Simulation of the Medical Linear Accelerator Electron Beams Absorption by ABS-Plastic doped with Metal

In this paper the numerical simulation results of the dose spatial distribution of the medical electron beams in ABS-plastic doped with different concentrations of lead and zinc are shown. The dependences of the test material density on the lead and zinc mass concentrations are illustrated. The depth dose distributions of the medical electron beams in the modified ABS-plastic for three energies 6 MeV, 12 MeV and 20 MeV are tested. The electron beam shapes in the transverse plane in ABS-plastic doped with different concentrations of lead and zinc are presented

Concurrent Thermochemoradiotherapy in Glioblastoma Treatment: Preliminary Results

Glioblastoma is the most frequent and aggressive primary brain tumor. The patient can be alive with this pathology using the modern standard of intensive combined treatment less than 2 years. Between December 2013 and August 2017, 30 patients with newly diagnosed supratentorial glioblastoma had received concomitant chemoradiotherapy with transcranial radiofrequency hyperthermia. The gross total or the subtotal resection of the tumor was made previously in all cases. The median follow-up time after operation achieved 12 months (95% confidence interval (CI): 8.5–23 months) in this study. The median disease-free survival time was 9.6 months (95% CI: 7.2–19.0 months). The median overall survival time of patients included in the study was 23.4 months. No increase in the systemic side effects of chemotherapy was found compared with the frequency described in the population. Preliminary results had shown that the usage of concomitant thermochemoradiotherapy with transcranial radiofrequency hyperthermia improves progression-free survival rates. Overall survival rates also tended to increase. Given the absence of severe complications, it is necessary to continue research to achieve statistically significant results

ADAPTATION OF LINEAR-QUADRATIC MODEL FOR PLANNING NEUTRON THERAPY REGIMENS

Based on the fact that the parameters of the linear-quadratic model for neutron therapy were found, the comparison of single therapeutic doses in neutron therapy, calculated using the TDF (time-dose-fractionation) and linear-quadratic (LQ) models were carried out. The calculation results were shown to be in good agreement. We also compared the degree of discrepancy in results calculated using the TDF and LQ models between neutron therapy and gamma therapy. It was shown that the use of the linear-quadratic model designed for neutron therapy is capable of providing adequate control for radiation-induced tissue reactions

Electron beam absorption in 3D-printed polymer samples with different infill densities

In this work, we study the efficiency of electron absorption by the plastic samples produced using 3D printing with different infill densities. We investigate the influence of the print layer orientation relative to the electron beam axis on the radiation dose distribution. It is possible to produce plastic samples with different infill by fused deposition modelling. Ten polymer test samples with the infill density ranging from 10% to 100% are printed and studied experimentally using a 6 MeV electron beam of an MIB-6E betatron. GafChromic EBT3 films are used for the dose measurement. When the infill is above 70%, the difference of dose distribution uniformity cannot be distinguished for the two print layer orientations. Therefore, these samples can be used for electron beam formation