ESTRO 2022 - Abstract Book

S1354

Abstract book

ESTRO 2022

With respect to dose degradations, the largest under dosage (12%) was observed for the thick lead (Ø2.2mm) and 7.5 cm SW build-up, while the smallest under dosage (6%) was observed for the Ø1.6mm lead and 2.5 cm SW build up. Under dosage was localised behind the leads in the beam direction and had approximately the same width and shape as the leads themselves. No overdosage due to backscatter radiation could be observed with neither films nor radiochromic dosimeters.

Conclusion Both lead thicknesses caused dose degradations, with the smallest shadowing effect measured for the thin lead (Ø1.6 mm). Since underdosage was localised in the beam direction downstream of the leads, its effect could be minimized in patient plans by using more than one field at different incidence angles.

PO-1572 Development of deformable 3D anthropomorphic dosimetry systems for proton therapy

S. Jensen 1 , T. Erichsen 2 , M. Jensen 1 , P. Balling 3 , J. Petersen 4 , P. Poulsen 1 , L. Muren 1

1 Aarhus University, Department of Clinical Medicine, Aarhus, Denmark; 2 Aarhus University, Deparment of Engineering, Aarhus, Denmark; 3 Aarhus University, Department of Physics and Astronomy, Aarhus, Denmark; 4 Aarhus University Hospital, Department of Medical Physics, Aarhus, Denmark