Thesis

Adaptive dose reconstruction with online in-vivo range verification in particle therapy

• Call:

  ProtoTera Call 2021/1

• Academic Year:

  2021/2022

• Supervisor:

  Joao Seco

• Co-Supervisor:

  Patrícia Gonçalves

• Host Institution:

  LIP - Laboratório de Instrumentação e Física Experimental de Partículas

• Granting Degree Institution:

  Instituto Superior Técnico (Universidade de Lisboa)

• Typology:

  Mixed

• Abroad Institution:

  Instituto Superior Técnico (Universidade de Lisboa)

• Abroad Supervisor:

• Abstract:

  Particle therapy using protons and ions promises high dose conformity due to its characteristic localized dose deposition. The theoretically achievable conformity is often compromised due to the concurrent sensitivity to uncertainties in patient setup, daily anatomy, and dose calculation. Current approaches to monitor particle ranges during treatment hope to mitigate the influence of these uncertainties, effectively minimizing the robustness requirements for the underlying treatment plans. While range verification methods show promising results and start to find their way into the clinic, it is not fully clear how to maximize the benefit of range information. In addition, it’s also not clear what is the needed precision for range measurements done in patients, using a variety of measuring devices such as dual energy CT, prompt gamma or proton imaging (such as proton tomography etc). The underlying issue is the required explicit decision if a detected range difference is acceptable or not. Some violations might be in-line with previous assumptions when designing the treatment plan, while others might be compensated for in later treatment sessions. Making these quantitative range-information based decisions mainly boils down to inferring the changes to the underlying dose distributions from the range measurements. Yet so far there is no methodology to accurately quantify these changes to the dose.