ESTRO 2025 - Abstract Book

S3667

Physics - Quality assurance and auditing

ESTRO 2025

effective tissue phantom ratio (TPR) data, which was compared to reference 'golden beam' data.

Results: A mean error of -0.2 ± 0.3 mm was found for all printed dimensions and detail diameters across all blocks, with limited variation seen according to detail type, size and orientation. Measured radiodensities for each infill varied by up to 198 HU between centres, with estimated water equivalent infills varying by up to 17.6%. Calculated water equivalent depths formed using combinations of the blocks varied by up to 3.2 mm between centres, with measured TPR data varying by up to 1.2%. Effective TPR data, plotted against water-equivalent depth for all centres, lay within 2 SD of both the mean values and the reference TPR curve.