ESTRO 2024 - Abstract Book

S4628

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTR0 2024

Results:

In the context of the 20-week conceptional pregnancy, the fetus dose originating from the photon plan ranged from 5.01 ±0.003mSv/Gy to 0.88 ±0.0005mSv/Gy from insert 1-7, respectively. Without including imaging dose, it was shown that for a breast treatment plan with a target dose of 40.05Gy in 15 fractions, the threshold of 100mSv will be greatly exceeded (see figure 2). The total neutron dose (20% uncertainty) ranged from 0.75 ±0.15mSv/Gy to 0.20 ±0.04mSv/Gy, respectively. BDTs are also sensitive to fast neutrons and the BD manufacturer's specification suggests a 1:10,i.e., thermal:fast ratio. However, existing research indicates a much lower response, approximately 1:19 times more sensitive to thermal neutrons. [18] On the other hand, BDs are also sensitive to protons, though this impact is expected to be low. [19] The MC simulations of the proton plan showed that the primary protons could contribute to the BDs readings up to inserts 4-5. It is important to note that the data presented here has not been adjusted yet for both contributions, meaning that BD readings may be slightly overestimated.