Experimental validation of Monte Carlo dose calculations about a high-intensity Ir-192 source for pulsed dose-rate brachytherapy

Med Phys. 1995 Jun;22(6):821-9. doi: 10.1118/1.597484.

Abstract

Despite widespread use of high-intensity Ir-192 remotely afterloaded sources, no published measured or calculated dose-rate tables for currently used source designs are available. For a pulsed dose-rate Ir-192 source, both transverse axis (0.5-10 cm) and two-dimensional polar dose-rate profiles (1.5, 3, and 5 cm) were measured with thermoluminescent dosimetry in a solid water phantom. Dose rates were normalized to measured air-kerma strength, and the source geometry was verified by pinhole autoradiography and transmission radiography. At each measurement point, dose rates were calculated by a Monte Carlo photon transport (MCPT) code, which realistically modeled the experimental phantom, source, and detector geometry. Agreement between MCPT absolute dose-rate calculations and measurements averaged 3% and was less than 5%, demonstrating that Monte Carlo simulation is an accurate and powerful tool for two-dimensional dosimetric characterization of high activity Ir-192 sources.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Brachytherapy / instrumentation
  • Brachytherapy / methods*
  • Humans
  • Iridium Radioisotopes / therapeutic use*
  • Luminescent Measurements
  • Mathematics
  • Models, Structural*
  • Monte Carlo Method*
  • Radiotherapy Dosage*
  • Reproducibility of Results

Substances

  • Iridium Radioisotopes