Fabrication, Characterizations And Dosimetric Evaluation Of Tannin-Based Rhizophora Spp. Particleboards As Phantoms For High Energy Photons And Electrons
Loading...
Date
2017-08
Authors
Mohd Yusof, Mohd Fahmi
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The aim of this study was to investigate the suitability of using fabricated Rhizophora spp. particleboards as phantom for high energy photons and electrons. Three types of particleboards made of Rhizophora spp. were fabricated namely the binderless, pretreated and tannin-based particleboards at three wood particle size ranges of 210-500 μm, 104-210 μm and ≤ 104 μm. The pretreated particleboard was fabricated using wood particles treated using steam while the tannin-based particleboard was fabricated by adding tannin adhesive at 10% treatment level to study their potential use as phantom material for high energy photons and electrons. The characterizations including density measurements, mechanical and physical properties, CT number, effective atomic number, relative electron density and attenuation properties were investigated to determine the most suitable particleboard to construct the phantoms. The attenuation properties of the particleboards were measured at low and high energy photons to determine their suitability as phantom at low and high energy photons. The percentage depth dose (PDD) of was measured at 6 and 10 MV (1.5 and 2.5 MeV) photons and 6 and 9 MeV electrons to determine their dosimetric properties at high energy photons and electrons. The addition of tannin as bio-adhesive material for Rhizophora spp. particleboard had improved the physical and mechanical properties of the particleboards. The investigation of attenuation properties found that the fabricated particleboards were close to the calculated value of water using XCOM computer program at low and high energy photons. The particle size ranges and method of fabrication did not give significant difference to the mass attenuation coefficients of Rhizophora spp. particleboards. The Rhizophora spp. particleboard samples with the optimum properties were used to construct the phantom set with 30 cm 30 cm 30 cm (L W H) for dosimetric evaluation at high energy photons and electrons. The output calibration measurement of absorbed dose at dmax at 6 and 10 MV photons showed good agreement between the Rhizophora spp. particleboards and water at percentage difference of 1.8 and 6.1% respectively. The PDD was measured at 6 and 10 MV photons as well as 6 and 9 MeV electrons using ionization chamber and EBT2 film dosimeter. The PDD curves of Rhizophora spp. particleboards showed good agreement to water and solid water phantoms within 4 and 12% percentage of discrepancies at 6 and 10 MV photons respectively. The study on beam profile at dref and dmax for Rhizophora spp. particleboards showed good dose uniformity and consistent to the solid water phantoms. The PDD curves at high energy electrons showed an agreement to water and solid water phantoms within 6 and 8% at 6 and 9 MeV electrons respectively. The dosimetric properties of Rhizophora spp. particleboards showed good consistency between the PDD measurements using ionization chamber and EBT2 films. Based on the results, the Rhizophora spp. particleboards bonded with tannin can be recommended as water equivalent phantom material for quality control and dosimetry works at high energy photons and electrons in radiotherapy. The overall results of the study had fulfilled the objectives of the study.
Description
Keywords
Fabricated Rhizophora spp. particleboards , as phantom for high energy photons and electrons.