Acceptance for clinical use of a treatment planning system with IMRT and VMAT techniques

Abstract

Purpose: In this work the set of measurements and results to test the reliability of the calculated absorbed dose by our treatment planning system (TPS) for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) is reported.

Method: A set of measures was performed, both point and planar absorbed dose, selecting a set of conventional and IMRT and VMAT treatment fields. A gamma criteria 3 mm distance to agreement and 3% dose difference (referred to the maximum dose) was used for the planar distribution analysis, using a 10% of maximum dose as threshold. Based on this set of measures the confidence limits were calculated for the IMRT and VMAT plans, and compared with the reference values given in AAPM TG119 document.

Results: The average percentage deviation of point dose measures was lower than 0.5% for conventional fields and lower than 1% for IMRT and VMAT fields. Calculated confidence limits were 3.6% and 4.6% for point dose and almost zero for planar dose distributions, for IMRT and VMAT respectively.

Conclusions: Our confidence levels improve significantly the AAPM TG119 reference levels both for point and planar doses, thus ensuring the reliability of the TPS performing IMRT and VMAT dose calculations.