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Item Open Access Tuning effective spot size parameter in Acuros XB algorithm for EdgeTM radiosurgery machine(Mahidol University, 2021) Warinthorn Rattanaareeyakorn; Puangpen Tangboonduangjit ; Nualjun Stansookcan affect the dose calculation. One important matter is the effective spot size parameter (ESS). The ESS can affect the calculated beam profile shaping, especially penumbra region and output factor in a small beam. Inappropriate ESS can lead... to improper isodose distribution in treatment planning. So, the aim of this research was to tune the ESS for the Acuros XB algorithm and to perform the small field output factor to evaluate the parameter performance. The ESS was varied separately in X and YItem Open Access Evaluation of the dosimetric leaf gap for VMAT-SBRT in small target volumes(Mahidol University, 2023) Grit Phianpholdeesakun; Puangpen Tangboonduangjit; Suphalak Khachonkhamto be performed effectively. One of the most important steps in the commissioning process, the MLC modeling, depends on the MLC parameters of diametric leaf gap (DLG) and leaf transmission (LT) for Eclipse-based treatment planning. Inappropriate MLC parameters... lead to poor agreement between the measured dose and the planned dose. For clinical application, many studies suggest that DLG adjustment must proceed carefully because it could compensate for the partial leaf transmission effect. This study aimsItem Metadata only Evaluation of dose calculation algorithm accuracy in eclipse treatment planning system for small fields(Mahidol University. Mahidol University Library and Knowledge Center, 2024) Panun Sritubtim; Puangpen Tangboonduangjit; Nualjun Stansookpronounced in small-field conditions. Since Varian recommends using multileaf collimators (MLC) instead of collimator jaws for small field delimitation and claiming the superior accuracy of AXB in the heterogeneity, this study aimed to evaluate the dosimetric... in the test on heterogeneity with a higher percentage difference. Superior agreement of AXB could observe only for field ≥3×3 cm2 which reflects the improper value of the effective spot size. Generally, AAA achieves a better deal with measurements (using TRSItem Open Access Monte carlo simulation of occupational eye lens dose in nuclear medicine procedures(Mahidol University. Mahidol University Library and Knowledge Center, 2022) Pakjira Morhrasi; Krisanat Chuamsaamarkkee; Putthiporn Charoenphun; Chayanit Jumpeeincreased as expected. At 50 cm, the eye lens dose rates were dramatically dropped to 1.16, 0.46 and 0.14 µSv/MBq/hr for 18F, 131I and 99mTc respectively. For impact of shielding, the performance of the shielding effected by the thickness of shielding... analyzed for several commercial syringe and vial shields. The maximum number of procedures for shielding and non-shielding situations was also estimated based on annual occupational eye lens dose limit to evaluate safety procedures. Hence, this study couldItem Metadata only Lesion detectability in tomographic imaging of radioiodine-131(Mahidol University. Mahidol University Library and Knowledge Center, 2016) Supakiet Piasanthia; Putthiporn Charoenphun; Krisanat Chuamsaamarkkee. The goal of this work was to evaluate the lesion detectability and effects of acquisition time as well as scatter correction on tomographic imaging of 131I. This work also aimed to determine the optimised acquisition time for 131I SPECT. The NEMA IEC Body....15 mL, diameter of 13 mm), the qualitative results were enhanced when prolonging acquisition time and performing scatter correction. The effects of acquisition time and scatter correction were clearly seen through a quantitative method. The CNRsItem Open Access Investigation on the efficiency of modified activated carbon for iodine-131 removal from a synthetic urine(Mahidol University., 2023) Sasiprapha Pochun; Putthiporn Charoenphun; Krisanat Chuamsaamarkkee; Pongtanawat Khemthong; Mahidol Universityperformed with (131)I synthetic urine concentrations of 0.5, 1, 2, and 3 μCi/mL at various contact times ranging from 3 minutes to 7 hours. The effect of adsorbent dosage was also investigated by varying the sample weights of 0.25, 0.50, 0.75, and 1.00 gram... was conducted to obtain the adsorption capacity data and study the factors affecting the (131)I removal efficiency. Furthermore, the column experiment evaluated the possibility of (131)I removal from the urine in the dynamic system under different concentrationsItem Metadata only Commissioning and Validation of Compass System for VMAT patient specific quality assurance(Mahidol University. Mahidol University Library and Knowledge Center, 2016) Jeerawat Pimthong; Lalida Tuntipumiamorn; Nuanpen Damrongkijudom.85 ± 0.50, -1.87 ± 0.39, - 1.33 ± 0.98, -0.61 ± 0.65 and -1.55 ± 0.24, respectively. Furthermore, the comparison of DVHs between Eclipse calculated dose and COMPASS reconstructed dose software was also evaluated. The results from the prostate VMAT plans... and COMPASS measured dose was less than 3% which is acceptable. Taken all together, it indicated that using COMPASS QA system along with Matrix Detector (IBA dosimetry) can be an effective tool for 3D dose pre-treatment verification of VMAT plans