title: Optimal radiation shielding for beta and bremsstrahlung radiation emitted by (89)Sr and (90)Y: validation by empirical approach and Monte Carlo simulations.
abstract: OBJECTIVE
  High-energy beta emitters such as Strontium-89 ((89)Sr) and Yttrium-90 ((90)Y) are becoming increasingly popular nuclear therapy sources in Japan for treating cancer. Various characteristics of materials must be considered when designing radiation protection device for high-energy beta emitters. We empirically measured and simulated dose equivalents of beta and bremsstrahlung radiation arising from (89)Sr and (90)Y radiation shielded with various materials and determined optimal shielding materials against these sources.
  
  
  METHODS
  The dose equivalents of (89)Sr and (90)Y determined experimentally using an ionization chamber survey meter were compared with those of Monte Carlo simulations. The relative dose equivalents of beta and bremsstrahlung radiation separately transmitted by changing the thickness of acrylic, aluminum, iron, lead and tungsten shielding materials were simulated.
  
  
  RESULTS
  Dose equivalents were consistent between the empirical measurements and the simulation to within ±5%. Shielding ability was more effective in the order of tungsten, lead, iron, aluminum and acrylic against both (89)Sr and (90)Y. The amount of beta and bremsstrahlung radiation transmitted through tungsten and lead was relatively small. Although such high-density material generates much bremsstrahlung radiation, it absorbs the bremsstrahlung radiations.
  
  
  CONCLUSIONS
  Tungsten was the optimal material for efficient shielding against (89)Sr and (90)Y radiation and preferable among operators. The present findings provide useful information about how to define an appropriate shielding strategy for high-energy beta emitters.
authors.affiliation: Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Murata
authors.forename: Kenta
authors.initials: K
authors.lastname: Miwa
authors.forename: Fumiyasu
authors.initials: F
authors.lastname: Matsubayashi
authors.forename: Kei
authors.initials: K
authors.lastname: Wagatsuma
authors.forename: Kenta
authors.initials: K
authors.lastname: Akimoto
authors.forename: Toshioh
authors.initials: T
authors.lastname: Fujibuchi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Miyaji
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takiguchi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Koizumi
mesh_terms: D001610:Beta Particles / Q000009:adverse effects*; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes / Q000009:adverse effects
chemical_list: D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes