ESTRO 2024 - Abstract Book

S3223

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

within the three regions in the anthropomorphic phantom change depending on the range of the dose bins. When using a binning representative for the RT fraction (dose range from 0 to 1.8 Gy with a bin size of 0.1 Gy), CT and CBCT dose distributions fall within the low-dose region, precisely within the first bin. This result was found independently of the organ’s location, that is, for organs in any of the three regions. In the case of the DVHs from CBCT simulation (dose range from 0 to 2.3 Gy with a bin size of 0.1 Gy), results were similar, with the dose distribution skewed towards the first bin. Therefore, in comparison to DVHs from one RT fraction, imaging doses can be considered homogenously distributed and added to the mean RT dose if the linear non-threshold risk model is used for SC risk assessment. If a different risk model based on dose distribution is used, the mean dose from imaging could be added to the RT dose for each voxel of the organ.

Conclusion:

Considering the dose range and the DVH, absorbed doses from imaging procedures could be assumed to be homogeneous in comparison to doses from RT. Given that mean imaging organ doses can be calculated using commercial software applications [1], they could be easily integrated into risk assessment.

Keywords: second cancer risk, total dose, imaging doses

References:

1. De Mattia C, Campanaro F, Rottoli F et al 2020 Eur. Radiol. Exp. 4:14.