67129 - Health Physics

Learning outcomes

At the end of the course the student has gained the basic knowledge on the most important and interesting topics in the field of Health Physics. In particular the student is able:  - to understand the different types of interactions of ionizing radiations with matter and their biological effects; - to understand the problems related to the radioprotection of workers and population; - to know the most important kinds of radiation detectors; - to use an acquition chain for alpha or gamma spectrometry.

Course contents

Ionizing radiation: interactions of high-energy photons with matter: photoelectric effect, Rayleigh scattering, Compton scattering, pair production, photonuclear interactions. Interactions of charged particles with matter. Bethe-Bloch formula. Bragg peak and particle range. Interactions of neutrons with matter. LET (Linear Energy Transfer).

Biological effects of ionizing radiation: mechanisms of radiation damage: direct and indirect action of ionizing radiation. The free radicals. Effects of radiation on cells: DNA damage and survival curves for viruses, bacteria and mammalian cells. Radiosensitivity of the cell in relation to the cell cycle phase. Relative Biological Effectiveness (RBE). Effects of radiation on humans: deterministic and stochastic damage. Epidemiological studies.

Dosimetry of ionizing radiation: main dosimetric quantities: exposure, absorbed dose, equivalent dose and effective dose. Weight factors for different types of ionizing radiation and for the different tissues of the human body.

Basics of radiation protection: principles of radiation protection. Concept of risk index. Classification of work areas and occupationally exposed workers. Dose limits.

Radiation detectors: gas detectors, scintillation detectors and solide state detectors. TLD dosimeters. Electronics for signal acquisition and processing. Alpha and gamma spectra analysis.

Introduction to alpha spectrometry: Calibration of a Multi-Channel Analyzer. Energy loss produced by an absorbing material. Laboratory practice with a silicon surface barrier detector for alpha spectrometry.

Introduction to gamma spectrometry: Gamma ray sources. Gamma spectra analysis. Laboratory practice with a CdTe detector.

Introduction to X-ray imaging techniques: X-ray tubes and detectors for digital radiography.  Characteristic parameters of an X-ray imaging detector. Outline of X-ray Computed Tomography and its applications in the medical, industrial and Cultural Heritage fields. Laboratory practice with an acquisition system for digital radiography and Computed Tomography.

 

Readings/Bibliography

• J.E. Coggle: “Biological effects of radiation”, Taylor & Francio Ltd, London.
• H.E. Johns and J.R. Cunningham: “The Physics of Radiology”, Charles C. Thomas Publisher.
• G.F. Knoll: "Radiation detection and measurement", John Wiley & Sons, Inc.
• R.F. Laitano: "Fondamenti di dosimetria delle radiazioni ionizzanti", ENEA.
• F. Casali: "Appunti di Fisica dei neutroni con elementi di Fisica dei Reattori".

The slides will be available after each lecture on the course website.

Teaching methods

Classroom lectures. Laboratory practice during which the students will be divided into small groups. Practical activities also aim to make the students acquire processing and synthesis skills, as well as group work skills.

Assessment methods

The final exam aims to assess the achievement of the main learning objectives of the course:

■ understanding of mechanisms of ionizing radiation-matter interaction and the resulting biological effects in living organisms;
■ understanding of the issues related to radiological protection of workers and the population in activities involving the use of ionizing radiation;
■ knowledge of the main types of radiation detectors;
■ laboratory use of an acquisition chain for alpha spectrometry and gamma of a system of X-ray imaging
 
After each laboratory activity the students are required to write a written report that can be prepared either individually or in group.

The final exam consists in a discussion on the topics covered in classroom lessons and on laboratory activities.

Teaching tools

Video-projector and PC.

Dedicated student laboratory for alpha and gamma spectrometry.

Laboratory for X-ray imaging.

The teaching material is available on the website: https://campus.unibo.it/

Office hours

See the website of Maria Pia Morigi