PT Journal
AU Rivard, MJ
   Granero, D
   Perez-Calatayud, J
   Ballester, F
TI Influence of photon energy spectra from brachytherapy sources on Monte Carlo simulations of kerma and dose rates in water and air
SO Medical Physics
JI Med. Phys.
PY 2010
BP 869
EP 876
VL 37
IS 2
DI 10.1118/1.3298008
LA English
DE biomedical materials; brachytherapy; dosimetry; iodine; iridium; Monte Carlo methods; palladium; radioisotopes
AB Methods: For Ir-192, I-125, and Pd-103, the authors considered from two to five published spectra. Spherical sources approximating common brachytherapy sources were assessed. Kerma and dose results from GEANT4, MCNP5, and PENELOPE-2008 were compared for water and air. The dosimetric influence of Ir-192, I-125, and Pd-103 spectral choice was determined. Results: For the spectra considered, there were no statistically significant differences between kerma or dose results based on Monte Carlo code choice when using the same spectrum. Water-kerma differences of about 2%, 2%, and 0.7% were observed due to spectrum choice for Ir-192, I-125, and Pd-103, respectively (independent of radial distance), when accounting for photon yield per Bq. Similar differences were observed for air-kerma rate. However, their ratio (as used in the dose-rate constant) did not significantly change when the various photon spectra were selected because the differences compensated each other when dividing dose rate by air-kerma strength. Conclusions: Given the standardization of radionuclide data available from the National Nuclear Data Center (NNDC) and the rigorous infrastructure for performing and maintaining the data set evaluations, NNDC spectra are suggested for brachytherapy simulations in medical physics applications.
ER