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Copyright of Journal of Taibah University Medical Sciences is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the advance in radiotherapy delivery, the need for a method allowing for a precise dose calculation increased. Monte Carlo modelling of radiotherapy dosages has become an important methodology for the evaluation of dose and beam performance, especially given recent advances in radiotherapy. In this study, an Elekta equipped with an Agility multileaf collimator will be modelled and validated in order to be used in further studies. A 6 MV photon beam for the Elekta Synergy linear accelerator with an Agility head was simulated, adjusted, and confirmed using the BEAMnrc/EGSnrc algorithm. Tuning involved comparing percentage depth dose with measured data using different incident electron energies, as analyzed using the gamma index. The best energy so calculated was then used with different full half width maximums (FWHMs) and different angular divergences in order to tune the lateral profiles. Output factors for different field sizes were validated with measurements. Then, the validated model was checked for different depths. For PDD comparison, the best electron energy was found to be 6.6 MeV, where the gamma analysis is 100%. A 0.15 cm circle FWHM was found to have the best FWHM. with an angular diverge of 0.03°. The output factors match measured values, proving that the model can achieve a suitably high accuracy. The validated model can be used in advanced radiotherapy dose calculation such as in VMAT, IMRT, and Stereotactic radiotherapy. The model needs to be validated in future studies for smaller field sizes, surface dose, and out-of-field dosimetry. • Elekta linear accelerator equipped with Agility multileafs collimator were modelled, validated, and tuned. • Results: The energy for incident electron is 6.6 MeV with 0.15 cm circular spot size and 0.03 angular divergence. • The model needs to be validated in future studies for smaller field sizes, surface dose, and out-of-field dosimetry. [ABSTRACT FROM AUTHOR]

In this study, a 6 MV Elekta linear accelerator was modelled and validated for in-field dosimetry against measurements by comparing the output factors, percentage depth dose, and lateral profiles. The resultant lateral profiles for the validated model were then compared with measurements for the out-of-field region up to 60 cm off-axis. It was initially found that there were discrepancies between the calculated and the measured profiles in the out-of-field region from 10 to 60 cm off-axis. Hence, two main adjustments were made to the length of jaws and materials of some of the head components in the LINAC model so as to be exactly as described by the manufacturer in order to acquire the best possible agreement with the measured values. Also, small head components such as the ion chamber, mirror, and Mylar sheet are included in the model to improve the results. Only in-line components were included in the model; the surrounding shielding components were excluded. The results after modifications of the head model showed good agreement with measurements up to 40 cm of field; however, from 40 to 60 cm there are still discrepancies of up to 80%, and the model underestimates the measured doses. Background radiation was measured inside the LINAC room and added as an error bar to measurements, which reduce the difference to 15% at distal points. This could possibly be due to the fact room scatter was not included in the model. • A 6 MV Elekta linear accelerator was modelled and validated for in-field and out-of-field dosimetry. • Precise material and dimension need to be considered in modelling. • No need to include outer shielding in modelling for out-of-field dosimetry. [ABSTRACT FROM AUTHOR]

W3+-doped multicomponent B 2 O 3 -SiO 2 -ZnO-Na 2 O glasses in a range of concentrations (0–6 mol %) have been manufactured using the melt quenching method. The result of replacing Na 2 O with WO 3 on the structure of zinc borosilicate glasses was examined using XRD. The density of the glass system has been determined using Archimedes' method. The substitution of Na 2 O with WO 3 in the glass composition would result in increased density and a decrease in molar volume. The incorporated WO 3 longitudinal velocities (V L m/s) increased from 4775 to 5120 and shear velocities (V S) increased from 2735 to 2955. The elastic moduli resulted in a uniform behavior when WO 3 increased, and the values ranged from 72.6 to 121.1 GPa for longitudinal modulus, 23.8–40.3 GPa for shear modulus, 40.8–67.3 GPa for bulk modulus, and 59.8–100.9 GPa for Young's modulus. The Debye temperature (θ D) increases from 431.71 to 506.33 as an increase in WO 3. Higher (θ D) indicates stronger atomic bonds and stiffer glasses. The elastic moduli based on the Makishima-Mackenzie model have been investigated. The trend indicates an increase in (Lth) varied between 137.7 and 219.1 GPa, (Gth) ranged from 38.7 to 50.3 GPa, (K) ranged from 86.16 to 152 GPa, and (Y) varied between 95.6 and 128.8 GPa, with an increase in the concentration of WO 3. The Phy-X program was used to determine the shielding characteristics for the samples, including mean free range (MFP), effective atomic number (Z eff), and neutron. Z eff increases along with WO 3 concentration and MFP decreases. The increase in the (FNRCS) due to the rise in sample density is linked to the concentration of WO 3. FNRCS (cm−1) values are 0.123 for SW 0 , 0.128 for SW 1 , 0.137 for SW 2 , 0.143 for SW 4 , and 0.162 for SW 6. It was determined that SW 6 had the best shielding capacity based on the MFP and Z eff values. This could have promising implications for various applications where radiation shielding or protection is necessary. This suggests that these glasses offer superior features that make them effective for shielding. • 21SiO 2 -13ZnO-(17-x) Na 2 O-xWO 3 (0 ≤ x ≤ 6 mol %), glasses were manufactured. • Density increases along with their WO 3 concentration. • Longitudinal velocities (V L) and shear velocities (V S) are increased. • It was determined that SW 6 had the best shielding capacity. [ABSTRACT FROM AUTHOR]