ESTRO 2024 - Abstract Book

S3727

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

ESTRO 2024

Results:

The average value of V 100% to PTV_Prescribe was 97.22% ranging from 82.09% for case 3 with collimator at 90° to 99.83% for case 5 with collimator at 60° (Figure 1).

Figure 1: V

to PTV_Prescribe according to collimator angle.

100%

In terms of monitor units (MU), a noteworthy trend emerged where the number of MU decreased as the collimator angle increased. This ranged from 1746.2 MU for case 10 with a collimator angle of 90° to 4000.5 MU for case 7 with a collimator angle of 0° (see Figure 2).

Figure 3: Variation of number of MU with collimator rotation

Conclusion:

Our findings indicate that for less complex target volumes, such as those focusing solely on the vertebral body, the coverage of PTV_Prescribe appears to be minimally affected by the collimator rotation. However, even within these simpler volumes, the collimator angle can significantly impact the number of MU required for treatment delivery.