Dosimetric assessment of the effective wedge angle of the internal wedge of the Elekta synergy linac using Elekta formula and analytical formula and comparison the results with Monaco treatment planning system computations

Abstract

In radiotherapy, the accuracy of dose calculation systems plays a key role in the treatment of cancer patients.

Objective: The current research aimed to evaluate the dose calculation accuracy of Monaco Treatment Planning System (TPS) in estimating the Effective Wedge Angle (EWA) using two different mathematical methods: Elekta formula and ICRU-24 formula.

Material and Methods: In this experimental study, EWAs for different field sizes (5 × 5, 10 × 10, 15 × 15, 20 × 20, 25 × 25, and 30 × 30 cm2) at standard angles (15°, 30°, 45°, and 60°) were computed by the Monaco TPS using two different analytical methods. The practical EWAs were measured according to the conditions outlined in the Elekta formula and the ICRU-24 formula, and these measurements were compared with the results derived from the TPS.

Results: The planned and measured EWAs are consistent with the Elekta formula, and the error value was less than ± 0.5 in all radiation fields and EWAs. In the ICRU-24 formula, the maximum deviation was ± 2.6° between the computational and practical EWAs.