2Department of Biomedical Engineering, Akdeniz University Faculty of Engineering, Antalya-Turkey
3Department of Medical Physics, Istanbul University Institute of Oncology, İstanbul-Turkey DOI : 10.5505/tjo.2019.1876 OBJECTIVE
The purpose of the present study was to verify calculated dose rate profiles of Ir-192 for four different irradiation lengths and various numbers of dwell positions by using treatment planning system (TPS) calculations and Monte Carlo (MC) simulations.
METHODS
Dose rate profiles per air-kerma strength in µGy m2/h (abbreviated as U) were calculated on transverse
axis for irradiation lengths of 2, 3, 4, and 5 cm by Nucletron Oncentra TPS. The same irradiation scenarios
were simulated with Monte Carlo N-Particle (MCNP) Transport Code. The MC and TPS calculated
dose rate profiles were compared for all settings.
RESULTS
The difference between the calculated dose rate profiles by MC and TPS was found within 2% at an
interval of 2 mm?8 cm away from the source for all irradiation lengths. The largest discrepancy of 5.2%
was computed at a distance of 10 cm from the source for 5 cm irradiation length.
CONCLUSION
There is a good consistency between the calculated dose rate profiles by MCNP and Oncentra TPS. The
deviation between the calculated dose rate values slightly increases as the distance from the source center
increases >5 cm from the source, and its quantity depends on the number of dwell positions.