Dose Distribution of 192Ir HDR Brachytherapy Source Measurement using Gafchromic® EBT3 Film Dosimeter and TLD-100H Nor Shazleen Ab Shukor, Marianie Musarudin, Reduan Abdullah, Mohd Zahri Abdul Aziz Pertanika Journal of Science and Technology, 2022 This study aims to measure the radial dose function and anisotropy function F(r, θ) of high Dose Rate (HDR) 192Ir source in a fabricated water-equivalent phantom using Gafchromic® EBT3 film and TLD-100H and to compare the results obtained with the MCNP5 calculated values. The phantom was fabricated using Perspex PMMA material. For, the EBT3 films with a required dimension and TLD-100H chips were placed at r=1, 2, 3, 5, and 10 cm from the source. The F(r, θ) measurements were carried out at r=1, 2, 3, 5, and 10 cm with the angle range from 10° to 170°. The result of from EBT3 film and TLD-100H was in good agreement (2.10%±1.99). Compared to MCNP5, the differences are within 0.31% to 11.47% for EBT3 film and 0.08% to 10.58% for TLD-100H. For the F(r, θ), an average deviation with the MCNP5 calculation is 4.94%±2.7. For both and F(r, θ), the effects are prominent at r=10 cm. At this distance, the response of both Gafchromic® EBT3 film and TLD-100H shows less sensitivity as the dose followed the inverse square law. This work demonstrates that Gafchromic® EBT3 film dosimeter and TLD-100H are suitable dosimeters in 192Ir dosimetric measurements at a radial distance of ˂5 cm
Scoping review on gonadal effects in patients with pelvic irradiation Malaysian Journal of Medicine and Health Sciences, 2021
Effects of different volumes of inhomogeneous medium to the radial dose and anisotropy functions in HDR brachytherapy N S Ab Shukor, M Musarudin, R Abdullah, M Z Abd Aziz Journal of Physics Conference Series, 2020 The aim of this study is to study the effects of non –homogenous region closer to the HDR Brachytherapy source. Radial widths of 1, 3 and 5 cm of an inhomogeneous cylindrical area filled with bone and lung tissue in a water phantom are modelled in this study. The effects of this inhomogeneity to the g(r) and F(r,θ) of Nucletron 192Ir microSelectron HDR source are assessed. The results show that the assumption of homogeneous water leads to underestimation of the bone dose by the treatment planning system. Meanwhile, overestimation of the dose is observed in the surrounding area. A relative difference of up to 19% is calculated for the largest bone volume. Contrast results are observed for the lung inhomogeneity model. A relative difference of up to 12% is observed in the lung dose. The presence of inhomogeneous region in the water phantom affects the anisotropy function; at a radial distance greater than 5 cm. Our results indicate that the presence of bone and lung inside the water phantom affect the g(r) and F(r,θ) in HDR brachytherapy. The degree of the effects depends on the material, position and volume of the inhomogeneity area.
Measurement of backscatter factor for kilovoltage x-ray beam using ionization chamber and Gafchromic XR-QA2 film N S Ab Shukor, N H Mohd Asri, S M F Syed Jaafar, M S Rosnan, S A Abdul Aziz Iop Conference Series Materials Science and Engineering, 2018 Backscatter factor (BSF) is an important parameter in the determination of surface dose for kilovoltage X-ray beam. The purpose of this study was to measure the BSF for kilovoltage diagnostic X-ray beam, and compare the measured BSF between Gafchromic XR-QA2 film and shadow free (SFD) ionization chamber (IC). The parameters that may affect the BSF, such as tube voltage (kVp) and field size, were also studied. The results were in good agreement with the TRS 457, with deviation of less than 12 %. Based on the film study, the BSF obtained from the film measurement were found to be lower than that of the IC, with average difference of 26 %. It was also found that smaller field size resulted in lower effective energy, and the amount of photons which scattered back onto the surface were also smaller. This study demonstrated that the Gafchromic XR-QA2 film was not suitable for the application of small field size.
Dosimetry of Al2O3 optically stimulated luminescent dosimeter at high energy photons and electrons M F Mohd Yusof, N A Joohari, R Abdullah, N S Abd Shukor, A B Abd Kadir, N Mohd Isa Iop Conference Series Materials Science and Engineering, 2018 The linearity of Al2O3 OSL dosimeters (OSLD) were evaluated for dosimetry works in clinical photons and electrons. The measurements were made at a reference depth of Zref according to IAEA TRS 398:2000 codes of practice at 6 and 10 MV photons and 6 and 9 MeV electrons. The measured dose was compared to the thermoluminescence dosimeters (TLD) and ionization chamber commonly used for dosimetry works for higher energy photons and electrons. The results showed that the measured dose in OSL dosimeters were in good agreement with the reported by the ionization chamber in both high energy photons and electrons. A reproducibility test also reported excellent consistency of readings with the OSL at similar energy levels. The overall results confirmed the suitability of OSL dosimeters for dosimetry works involving high energy photons and electrons in radiotherapy.
Verification of relative output factor measurement using Gafchromic films for small-field radiosurgery photon beams. R Abdullah, M S Sapeei, N S A Shukor, M F M Yusof, M Mohamed, N R N Idris, A L Yusoff, A Zakaria, M Z A Aziz Iop Conference Series Materials Science and Engineering, 2018 Accurate dosimetry of small-field photon beams has always been difficult to achieve, due to the steep dose gradient and absence of lateral electronic equilibrium. The purpose of this study was to verify the measurement of relative output factor (ROF), which is one of the dosimetric parameter required for stereotactic radiosurgery (SRS) treatment planning. The ROFs for Radionics circular cone collimators with diameter in the range of 10.0 to 45.0 mm were measured using Gafchromic EBT2 and EBT3 films. The measurements were then compared with the ROFs obtained using a PinPoint ionisation chamber and Monte Carlo (MC) simulation. From the results, the ROFs measured by the ionisation chamber, EBT2, and EBT3 films were good agreement with the MC simulation, with deviations of less than 1.5, 2.6, and 5.0 % respectively. Based on the film dosimetry, the EBT2 film showed in a more reliable measurement for field size ranging from 15.0 to 45.0 mm, compared with EBT3. As a conclusion, based on the special characteristic of the small-field photon beams, ROF measurement using PinPoint ionisation chamber are being favoured, due to its accuracy. However, the EBT2 film can be used as an alternative, when high spatial resolution is required.
