title: Monte Carlo characterization of a new Yb-169 high dose rate source for brachytherapy application.
abstract: OBJECTIVE
  The objective was to characterize a new Yb-169 high dose rate source for brachytherapy application.
  
  
  METHODS
  Monte Carlo simulations were performed using the MCNP5 F6 energy deposition tallies placed around the Yb-169 source at different radial distances in both air-vacuum and water environments. The calculations were based on a spherical water phantom with a radius of 50 cm. The output from the simulations was converted into radial dose rate distribution in polar coordinates surrounding the brachytherapy source.
  
  
  RESULTS
  The results from Monte Carlo simulations were used to calculate the AAPM Task Group 43 dosimetric parameters: Anisotropy function, radial dose function, air kerma strength, and dose rate constant. The results indicate a dose rate constant of 1.12 +/- 0.04 cGy h(-1) U(-1), anisotropy function ranging from 0.44 to 1.00 for radial distances of 0.5-10 cm and polar angles of 0 degrees-180 degrees.
  
  
  CONCLUSIONS
  The data from the Yb-169 HDR source, Model M42, presented in this study show that this source compares favorably with another source of Yb-169, Model 4140, already approved for brachytherapy treatment.
authors.affiliation: Department of Physics and Applied Physics, University of Massachusetts Lowell, 1 University Avenue, Lowell, Massachusetts 01854, USA. mariocazeca@yahoo.com
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Cazeca
authors.forename: David C
authors.initials: DC
authors.lastname: Medich
authors.forename: John J
authors.initials: JJ
authors.lastname: Munro
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation*; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D011868:Radioisotopes / Q000032:analysis / Q000627:therapeutic use*; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D015018:Ytterbium / Q000032:analysis / Q000627:therapeutic use*
chemical_list: D011868:Radioisotopes; D015018:Ytterbium