The bolus is also known a tissue compensation that has material similar to body tissue and placed directly onto the skin surface for radiation therapy. This study aims to characterize and evaluate the synthesized homemade bolus using Natural Rubber, Paraffin Candle, Play-Doh, and Paraffin Wax Pure for radiation therapy using a photon beam. Several dosimetry properties of the synthesized of the bolus, including relative electron density (RED), transmission factor, attenuation coefficient, and percentage of surface dose (PSD), were investigated. All the synthesized bolus made with the same dimension of 11×11 cm2 with the thickness is 1 cm. CT-Scan was used to measure relative electron density (RED) where as LINAC 2300iX with energies 6 and 10 MV were used to evaluate percentage of surface dose. The RED value of all bolus material is in accordance with the provisions of bolus as a tissue compensation of the human body, which is almost the same as the value of HU in breast organs, skin, fat and adult bones. Large transmission factors and attenuation coefficients of each bolus correspond to bolus from paraffin candles as the default bolus of the hospital. The maximum bolus dose value increases when compared to measurements without bolus.

Background: The commissioning accuracy of Volumetric Modulated Arc Therapy (VMAT) need to be evaluated.Objective: To test and evaluate commissioning accuracy of VMAT based on the TG 119 protocols at local institution.Material and Methods: The phantom, structure sets, VMAT and IMRT beam parameter setup, dose prescriptions and planning objectives were following TG 119 guidelines to create local treatment plans of VMAT and IMRT. The local planning results were compared with the results of TG 119. Point measurement at high and low dose regions were measured using three ionization chambers with different active volumes (CC01, CC13, FC65G). The composite dose was measured by a 2D detector array and analyzed for the percentage of points passing the gamma criteria of 3 % dose difference (DD) and 3 mm distance-to-agreement (DTA) and 2 % DD and 2 mm DTA. Results: The local treatment plans of VMAT and IMRT capable to meet the dose goals criteria set by TG 119 except for C-shape hard. Three ionization chambers with various active volumes for point measurement showed an increase in the confidence limit (CL), the larger the active volume was found proportional to increase the value of CL. The results obtained from ion chambers CC01 and CC13 could met the dose criteria set by TG 119, but results obtained from ion chamber FC65G fail the criteria. All gamma evaluation results show more than 95% data points pass the criteria of 3% DD and 3 mm DTA and the gamma index CL results fall within the TG 119 criteria, which is below 12.4.Conclusion: TG 119 methodology and recommendations have successfully been used to evaluate commissioning accuracy of VMAT. The CL value of the study could be used as a reference and recommendation to evaluate the accuracy and integrity of treatment planning and treatment delivery systems of VMAT and IMRT.

In radiation therapy, bolus material is often used for increased surface dose, compensate for surface irregularities and internal heterogeneities. Bolus has properties equivalent to water and soft tissue. In this study, the mixture of Silicone Rubber (SR) and Bismuth was used for bolus fabrication and then compared to commercial boluses such as Paraffin, Play-Doh, and Paraffin Wax. The study aims to evaluate the comparison of relative electron density (RED), effective mass attenuation coefficient, transmission factor, percentage of surface dose (PSD), and Percentage Depth Dose (PDD) for all boluses. The bolus was made with the size 11 × 11 × 0.5 cm3. Physical density of the synthesized bolus was assessed by computerized tomography (CT) Scanning. The results of the RED analysis for the mixture of Silicone Rubber (SR) and Bismuth, Paraffin, Play-Doh, and Paraffin Wax were 0.954; 0.743; 0.933; and 0.878, respectively. The values of RED for all boluses has a similar to water and soft tissue. These results prove that the bolus is equivalent to soft tissue density such as fat, breast, lungs, and liver. Furthermore, for other dosimetry tests such as transmission factors and attenuation coefficients using Linear Accelerator (LINAC) with photon energy sources 6 and 10 MV. In general, Percentage of surface dose at 6 MV is higher than 10 MV. The highest percentage of the surface dose was achieved by paraffin wax at 6 MV energy by 85%. For effective mass attenuation coefficient result, the highest is the mixture of silicone rubber and bismuth at -0.0030 cm2/g for 6 MV and Play-Doh at -0.0114 cm2/g for 10 MV.

Several previous studies described that radiation neutrons are produced by 10 MV X-ray beams operated linac. This study was performed to exercise the characteristic of profile and neutron depth dose for 15 MV X-ray beams and also to evaluate the contribution of neutron dose to the patient. The experiment used Linac iX with 15 MV X-ray beam, TLD-100, TLD-600, and phantom. The phantom was designed to evaluate the dose profile at cross-plane and diagonal axis. TLDs were calibrated separately by gamma and neutron sources. Gamma calibration was carried out using 137Cs source whereas neutron calibration was done using 252Cf source at BATAN Facility. Neutron dose equivalents were calculated on cross-plane and diagonal axis in 10 cm × 10 cm fields at 15 positions from the central axis, on the phantom surface and depths of 2 cm, 3 cm, and 15 cm. The percentage maximum neutron dose equivalent distributions were obtained around of 3 cm depth for cross-plane and diagonal axis. Furthermore, the dose profile of neutron at different depths and off-axis position are not symmetrical. Neutron dose in out-of-field had no significant response compared to the in-field. The relative neutron dose in out-of-field is 27% and 24% normalized to the maximum neutron dose at each depth on cross-plane and diagonal axis respectively.

Lung cancer has decreased mortality rates each year that can treat with radiotherapy. The radiotherapy module is own by 3D Slicer that is open-source software. The purpose is to determine the distribution of doses on the dose-volume histogram (DVH) and the percentage of the suitability of the 3D Slicer simulation results with the Treatment Planning System (TPS) at MRCCC Siloam Hospital. The data used were three Computed Tomographic images of lung cancer patients obtained from the MRCCC Siloam Hospital. The parameters analyzed included volume, the dose of the target volume, and organ at risk (OAR). Analytical studies were carried out by comparing the target volume with The International Commission on Radiation Unit (ICRU) Report 83 and comparing the OAR regarding dose tolerance. The dose distribution of all patients from the simulated 3D slicer for OAR met the tolerance limit reference recommendations. The Planning Target Volume (PTV) of all patients also matched the evaluation recommended by the ICRU Report 83. The percentage value of the suitability between the 3D Slicer and TPS results for all patients was above 95%. It shows that 3D Slicer can use as a recommendation software for initial radiotherapy planning studies.