This course aims at providing the students with knowledge about radiation therapy and emission tomography and their fundamental technological aspects. The first part of the course deals with the interaction of radiation with the biological tissue for better understanding the mechanisms ruling dose delivering in radiation therapy. Moreover, some outlines about radiobiology are given, for understanding radiation interactions with the DNA and the cellular response against radiation. Microdosimetry is also introduced for focusing on measurement techniques, which are capable of giving deeper information about the quality of radiation fields. Two emission diagnostic techniques (SPECT and PET) are discussed by focusing on the detection systems and the phenomena affecting their response. The operation principles of particle accelerators applied to radiation therapy are given for a better understanding of the engineering aspects linked to the patient treatment. The final part of the course discusses electron and X-ray therapy, both conventional and conformal, and hadrontherapy with protons and carbon ions. Boron Neutron Capture Therapy (BNCT) is also treated, together with the problematics linked to the use of research nuclear reactors and particle accelerators as neutron sources.

The student:

• knows the fundamental interactions of radiation with the biological tissue and the cellular response to radiation, the main emission diagnostic and radiation therapy techniques, the principles of operation of particle accelerators applied for radiation therapy and the detection techniques for dosimetry;
• can apply her/his knowledge for assessing the quality of radiation fields and the radiation dose (laboratory sessions);
• can judge critically the advantages and the problematics of different radiation therapy techniques;
• acquires skills for communicating her/his knowledge in the field of engineering techniques for radiation therapy.

Principles of Radiation Physics. Definition of absorbed dose and dose prescription in radiation therapy. Interactions (ionization, excitation and Coulomb scattering) of charged particles with biological tissues. Production of Bremsstrahlung X-rays. Inelastic interactions of intermediate-energy hadrons with biological tissues. Photonuclear reactions. Interactions of electromagnetic radiation with biological tissues. Interactions of neutrons with biological tissues. 

Outlines on radiation biology. Direct and indirect interactions of radiation with DNA. Survival curves. Relative biological effectiveness (RBE). The oxygen effect. Fractionation of radiation therapy.

Microdosimetry. Principles of microdosimetry. Microdosimetric spectra. The tissue-equivalent proportional counter (TEPC). Outlines on nanodosimetry.

Emission diagnostic techniques. Single Photon Emission Tomography (SPECT): collimation and detection of gamma rays, influence of Compton scattering. Positron Emission Tomography (PET): coincidence detection techniques, spatial resolution, random coincidence, attenuation and scattering, PET scintillators.

Principles of operation of particle accelerators. The Cockroft-Walton and Van de Graaff electrostatic accelerators. The betatron. The cyclotron. Resonant cavities (outlines). Linear accelerators for ions and electrons. The synchrotron (outlines).

Techniques for dose delivering. X-ray and electron radiation therapy: electron scatterers, Bremsstrahlung targets, flattening filters, collimators. Hadron-therapy: dual-scattering systems, modulators, spread-out of Bragg peak, active techniques. The gamma-knife and stereotactic techniques.

Boron Neutron capture Therapy (BNCT). Principles of BNCT. Neutron field tailoring for BNCT. Accelerator-based neutron sources for BNCT.

Course Organization

The course is structured in one semester with lectures of six hours per week. Seven experimental laboratories (duration about four hours per lab session) are offered, aiming at gaining experience with different types of radiation measurement techniques. Visits to radiation therapy, hadron therapy and BNCT facilities are organized in the framework of the course.

To attend the course a knowledge, at least at an elementary level, of electromagnetism is required. The principles of operation of radiation detectors will be outlined to non-nuclear engineering students before each laboratory session.

The evaluation consists in an oral examination. It aims at verifying the knowledge of the course topics, by focusing on the ability in understanding the physical and radiobiological aspects of different radiation therapy and diagnostic techniques. The student’s capability in evaluating the rationale of the engineering solutions to the main problematics of radiation therapy and dosimetry will also be verified. The first part of the exam foresees a critical discussion of one of the laboratory sessions. In particular, the student’s capability of carrying out autonomously a laboratory session will be verified. The student’s communication capabilities will be tested through discussions about the advantages of a given radiation therapy technique, the solutions adopted for dose delivery, the techniques for measuring the dose and for assessing the beam quality.