Thesis

Evaluating the Effectiveness of Mini-Beam Radiation in Cancer Therapy

• Call:

  PT-CERN Call 2020/2

• Academic Year:

  2020/2021

• Domain:

  Astrophysics

• Supervisor:

  Patricia Goncalves

• Co-Supervisor:

  Joao Seco

• Institution:

  Instituto Superior Técnico (Universidade de Lisboa)

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  Technological developments play an important role in the improvement of cancer therapy. Radiation-therapy is, in particular, a rapidly evolving field and it is used as a form of treatment for as many as half of the cancer patients [1]. The refinement of the treatment techniques improved patient care and led to an increase in the survival rate. Long term survivors are the ones who potentially benefit the most from the developments aiming to reduce the side effects of radiation-therapy. The most commonly chosen approach to affect the lesions without inducing side effects is improving the conformality of the dose delivery. In general, the approaches adopted in clinical practice aim to achieve tumor control by delivering a uniform dose to the target volume. In pre-clinical studies several other options have been investigated, which not always base their rationale on uniform dose distributions and conformality [2]. A prominent case is the micro- and mini-beam radiation therapy (MBRT), where a spatial pattern of high-dose beamlets alternates with low-dose valleys. This has been investigated in animal experiments with photon beams (MRT) at synchrotron facilities with photons and at cyclotron facilities with protons. MBRT has been investigated at two different spatial scales in the literature at the micrometer and millimeter scale. In both cases, the setup utilizes arrays of parallel thin radiation planes separated by short distances. In first approximation, along the transverse profile, the radiation can be modeled by a series of m equidistant rectangular peaks separated by valleys without direct delivery of the beam. The Goals of this thesis are to investigate how spatially fractionated mini-beams produce effectively tumor control; to perform Monte Carlo inter-comparison for chemical reactions present in codes such as TOPAS-nBIO, GEANT-DNA and gMicroMC and to establish which Monte Carlo is best suited for the description of spatially fractionated mini-beams.