Search

Background: Independent external audits play an important role in quality assurance programme in radiation oncology. The audit supported by the IAEA in Serbia was designed to review the whole chain of activities in 3D conformal radiotherapy (3D-CRT) workflow, from patient data acquisition to treatment planning and dose delivery. The audit was based on the IAEA recommendations and focused on dosimetry part of the treatment planning and delivery processes. Methods: The audit was conducted in three radiotherapy departments of Serbia. An anthropomorphic phantom was scanned with a computed tomography unit (CT) and treatment plans for eight different test cases involving various beam configurations suggested by the IAEA were prepared on local treatment planning systems (TPSs). The phantom was irradiated following the treatment plans for these test cases and doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. Results: The measurements were conducted for different photon beam energies and TPS calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms were within the agreement criteria, while the larger deviations were observed for simpler algorithms. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected. Conclusions: The audit helped the users to better understand the operational features and limitations of their TPSs and resulted in increased confidence in dose calculation accuracy using TPSs. The audit results indicated the shortcomings of simpler algorithms for the test cases performed and, therefore the transition to more advanced algorithms is highly desirable [ABSTRACT FROM AUTHOR]

Background: Clinical implementation of enhanced dynamic wedges (EDW) requires, as any other dynamic treatment, very serious quality assurance (QA) program. In this work, we presented the results of six-month evaluation of Varian enhanced dynamic wedges and detailed QA program for those wedges. Methods: The Sun Nuclear Daily QA Check 2 was used for QA purpose. The QA program included daily and monthly checks. The daily QA program included central axis dose and wedge angle measurements. Within the monthly QA program wedge factors and delivered STTs from the Dynalog files were checked. Results: Our daily QA measurements of dose and wedge angle showed the reproducibility error less than ±1.5%. On the other hand, monthly QA measurements of wedge factor the reproducibility error was less than ±0.5%. The monthly QA check of delivered STTs showed excellent agreement. Conclusion: During the six-month quality control we observed a good reproducibility in the delivery of EDW treatment. Also, the Sun Nuclear Daily QA Check 2 showed to be very satisfying in QA of the EDW treatment. [ABSTRACT FROM AUTHOR]