ESTRO 2024 - Abstract Book

S3577

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Results:

Figure 2a shows an example spline fit for the pair of films with a shield height of 114cm. All the spline fits were of a similar quality. Figure 2b shows the plot of the optimal shield height versus the treatment length of the patient (from foot to upper most target). For the 90% isodose level, the distance from the field was 15cm ± 1cm. The shield height followed a strong linear trend with respect to the total treatment length within each isodose level (R2 > 0.996). During our measurements, we observed an uncertainty of approximately 1cm. This included the film alignment and marking, profile stitching, and shield position errors. On average, a change by 1cm of the shield leads to a 1.5% and 2.6% change in isodose near the 90% and 80% isodose lines, respectively.