Thesis

Full-treatment proton therapy verification with simulation-optimized orthogonal prompt-gamma imaging systems

• Call:

  ProtoTera Call 2023/1

• Academic Year:

  2023

• Supervisor:

  Paulo Crespo

• Co-Supervisor:

  Hugo Simões

• Host Institution:

  LIP - Laboratório de Instrumentação e Física Experimental de Partículas

• Granting Degree Institution:

  Universidade de Coimbra

• Typology:

  Mixed

• Abroad Institution:

  Universidade de Coimbra

• Abroad Supervisor:

  Katia Parodi

• Abstract:

  Proton therapy (PT) improves dose conformation for complex shaped tumors. However, full clinical exploitation of PT is still challenged by uncertainties in the actual beam range. There are two main physical channels to explore in vivo monitoring of PT: (1) imaging beta+ decays using dedicated or commercial positron emission tomographs (PET); and (2) using prompt gamma imaging (PGI). Both PET and PGI rely on nuclear reactions between the projectile and the nuclei of the patient. Orthogonal PGI (O-PGI) systems consist of collimator slats interleaved with scintillator crystals. Previous simulation results using a full O-PGI system have demonstrated the ability of such a system to detect deviations in the position of the distal edge with an accuracy of 2 mm FWHM during irradiation of a homogeneous acrylic phantom with an energy of 130 MeV. The main objective of this work is to study the irradiation of relevant anatomical regions (e.g. head, thorax, pelvis, and craniospinal irradiation of pediatric patients) using anthropomorphic phantoms, including the entire planned irradiation treatment. Such studies will also include real-time monitoring of moving tumors (e.g., in the thoracic region affected by respiratory or cardiac motion). Other dose-disturbing mechanisms (e.g., patient mispositioning, tumor regression/progression) will also be introduced into the simulations in order to calculate their detectability with optimized O-PGI systems. At the end of this work, we hope to have defined a list of potential applications where the O-PGI system can provide effective feedback on treatment progress, both inter-fractionally (between treatment sessions) and intra-fractionally (in real time during treatment). This should increase the value of the O-PGI system, which will be a fundamental step towards the construction of a complete system and its future implementation in clinical practice.