Experimental validation of Monte Carlo dose calculations about a high-intensity Ir-192 source for pulsed dose-rate brachytherapy.
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.
Valicenti
R K
RK
Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Kirov
A S
AS
Meigooni
A S
AS
Mishra
V
V
Das
R K
RK
Williamson
J F
JF
D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D008163:Luminescent Measurements; D008433:Mathematics; D008961:Models, Structural; D009010:Monte Carlo Method; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results
D007496:Iridium Radioisotopes