ESTRO 2024 - Abstract Book

S5550

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

Results:

A total of 540 and 554 images were evaluated for the TPS and DSPS system, respectively. Overall, the set-up errors were very small for both systems. The percentage number of translation set-up errors within +/- 1mm was 99.82% in all directions for the TPS system. For the DSPS system, the percentage number of translation set-up errors within +/- 1mm was 99.82%, 99.64%, and 100% in the X, Y, and Z directions, respectively. The percentage number of rotational set-up errors within +/- 1° for the Rx, Ry, and Rz directions were 53.97%, 60.44%, and 70.79% for the TPS system and 66.85%, 68.36%, and 70.81% for the DSPS system, respectively. Figure 1 illustrates the translation and rotational set up errors for both systems.

Figure 1: Boxplot illustrating the translational (TOP) and rotational (bottom) set-up errors of the TPS and DSPS systems.

Compared to the DSPS system, the median RMS set-up errors for the TPS were larger in the X (0.11mm versus 0.09mm p=0.013), Rx (0.90° versus 0.80° p<0.001), Ry (0.80° versus 0.60° p=0.003) and Rz (0.60° versus 0.70° p=0.946) and smaller for the Y (0.12mm versus 0.16mm p<0.001) and Z (0.09mm versus 0.10mm p=0.029).

The response rate of the questionnaire was 66% (n=19). Table 2 summarizes the results of the questionnaire. The radiographers assigned similar ratings to both systems overall. Nonetheless, the DSPS had a significantly better rating