title: Dosimetric shield evaluation with tungsten sheet in 4, 6, and 9MeV electron beams.
abstract: In electron radiotherapy, shielding material is required to attenuate beam and scatter. A newly introduced shielding material, tungsten functional paper (TFP), has been anticipated to become a very useful device that is lead-free, light, flexible, and easily processed, containing very fine tungsten powder at as much as 80% by weight. The purpose of this study was to investigate the dosimetric changes due to TFP shielding for electron beams. TFP (thickness 0-15mm) was placed on water or a water-equivalent phantom. Percentage depth ionization and transmission were measured for 4, 6, and 9MeV electron beams. Off-center ratio was also measured using film dosimetry at depth of dose maximum under similar conditions. Then, beam profiles and transmission with two shielding materials, TFP and lead, were evaluated. Reductions of 95% by using TFP at 0.5cm depth occurred at 4, 9, and 15mm with 4, 6, and 9MeV electron beams, respectively. It is found that the dose tend to increase at the field edge shaped with TFP, which might be influenced by the thickness. TFP has several unique features and is very promising as a useful tool for radiation protection for electron beams, among others.
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Takahiro
authors: T
authors: Fujimoto
authors: Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, 54 Kawara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: hmon@kuhp.kyoto-u.ac.jp.
authors: Hajime
authors: H
authors: Monzen
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Manabu
authors: M
authors: Nakata
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Takashi
authors: T
authors: Okada
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Shinsuke
authors: S
authors: Yano
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Toru
authors: T
authors: Takakura
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Junichi
authors: J
authors: Kuwahara
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Makoto
authors: M
authors: Sasaki
authors: Clinical Radiology Service Division, Kyoto University Hospital, Kyoto 606-8397, Japan.
authors: Kyoji
authors: K
authors: Higashimura
authors: Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, 54 Kawara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
authors: Masahiro
authors: M
authors: Hiraoka
mesh_terms: D004583:Electrons / Q000627:therapeutic use*; D010209:Paper; D011835:Radiation Protection / Q000295:instrumentation*; D011874:Radiometry; D013499:Surface Properties; D014414:Tungsten
chemical_list: D014414:Tungsten
keywords: Electron beam; Radiation shield; Transmission; Tungsten paper