Background: Treatment planning systems (TPSs) are used for dose calculations
in dose delivery by after loading brachytherapy machines. Such planning
systems usually use simplified algorithms in their dose calculations.
Verification of dose distributions produced by TPS is of clinical importance
and is part of a quality assurance program. In this study, the dose
distributions generated by GZP6 TPS for two GZP6 sources were verified.
Methods: The evaluation was based on the inter comparisons between the
isodose curves obtained through Monte Carlo simulations, radiochromic film
measurements, and GZP6 treatment planning system. MCNPX Monte Carlo code was
used to simulate the sources. Dose measurements were performed in a perspex
phantom using Gafchromic? EBT radiochromic films. Comparisons between the
results obtained from MC, RCF, and TPS were performed by gamma function
calculations with 5% dose/2 mm distance criterion. Results: Based on gamma
calculations our results showed that there was good agreement between the
dose distributions obtained by the three aforementioned methods in both
transverse and longitudinal planes for the GZP6 source No.2. However, for
source No. 5, the agreement was good in the transverse plane but it was low
in the longitudinal plane. Conclusion: The results showed that dose
distributions certified by the GZP6 TPS for the GZP6 source No. 2 were
validated. However, for source No. 5 some discrepancies were observed.
Accurate knowledge of the activity of each active pellet in the source No. 5
can clarify the cause of the discrepancies.