title: Monte Carlo calculated TG-60 dosimetry parameters for the beta- emitter 153Sm brachytherapy source.
abstract: OBJECTIVE
  The formalism recommended by Task Group 60 (TG-60) of the American Association of Physicists in Medicine (AAPM) is applicable for beta sources. Radioactive biocompatible and biodegradable 153Sm glass seed without encapsulation is a beta- emitter radionuclide with a short half-life and delivers a high dose rate to the tumor in the millimeter range. This study presents the results of Monte Carlo calculations of the dosimetric parameters for the 153Sm brachytherapy source.
  
  
  METHODS
  Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate two-dimensional dose distributions around the source. The dosimetric parameters of AAPM TG-60 recommendations including the reference dose rate, the radial dose function, the anisotropy function, and the one-dimensional anisotropy function were obtained.
  
  
  RESULTS
  The dose rate value at the reference point was estimated to be 9.21 +/- 0.6 cGy h(-1) microCi(-1). Due to the low energy beta emitted from 153Sm sources, the dose fall-off profile is sharper than the other beta emitter sources. The calculated dosimetric parameters in this study are compared to several beta and photon emitting seeds.
  
  
  CONCLUSIONS
  The results show the advantage of the 153Sm source in comparison with the other sources because of the rapid dose fall-off of beta ray and high dose rate at the short distances of the seed. The results would be helpful in the development of the radioactive implants using 153Sm seeds for the brachytherapy treatment.
authors.affiliation: Agricultural, Medical and Industrial School, P.O. Box 31485-498, Karaj, Iran. msadeghi@nrcam.org
authors.forename: Mahdi
authors.initials: M
authors.lastname: Sadeghi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Taghdiri
authors.forename: S Hamed
authors.initials: SH
authors.lastname: Hosseini
authors.forename: Claudio
authors.initials: C
authors.lastname: Tenreiro
mesh_terms: D016880:Anisotropy; D001610:Beta Particles / Q000627:therapeutic use*; D001918:Brachytherapy / Q000706:statistics & numerical data*; D006801:Humans; D009010:Monte Carlo Method; D009369:Neoplasms / Q000532:radiotherapy; D011868:Radioisotopes / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000706:statistics & numerical data; D012493:Samarium / Q000627:therapeutic use*
chemical_list: D011868:Radioisotopes; D012493:Samarium