ESTRO 2024 - Abstract Book

S3255

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Results:

To stablish a base line for the machine’s deviation in this check, we performed the classic WL test with three validated phantoms from different vendors: Frameless SRS QA Target Pointer (Brainlab AG), Lucy phantom (Standard Imaging Inc) and the Varian Isocentre Cube (Varian), the obtained results for all three phantoms are within the accepted tolerance range, and then we created an average of the three phantoms to set our base line. Plan 2 Exactrac repositioning reduces the inherent machine deviation for off-isocenter targets. However, differences between radiation and mechanical field are greater when the target is at 3cm from the isocenter than those found at the isocenter. In this case, three of the five fields have a difference that exceed the tolerance, but when Exactrac correction is performed, one of these surpassed values becomes within tolerance. Plan 3 at all tables positions, WL results go beyond the accepted tolerance, and although Exactrac repositioning reduces the mechanical/radiation deviation for off-isocenter targets, only two of them become within acceptance values.

Conclusion: