06630 - Radiation Physics

Learning outcomes

The student will be familiar with the principles of dosimetry an their parameters, radiation protection (fundamentals and regulations), the production and properties of X-rays, their interaction with matter as well as the qualitative and quantitative analisys of the X-ray beam.

Course contents

The e.m. Radiation and the X-ray discovery
The spectrum of e.m. waves. Ionizing radiation and non-ionizing radiation.
Electromagnetic waves: wave model and corpuscolar model.
Wave-corpuscle Dualism
The X-ray discovery.

Radiation-matter interaction
Interaction of alpha and beta rays with matter.
Interaction of X and gamma rays with matter.
Definitions: Intensity, Fluence, cross Section and linear attenuation Coefficient.
Classical diffusion (Rayleigh scattering).
Photoelectric effect.
Compton scattering.
Pairs production.

X-ray production
X-ray spectrum: Bremsstrahlung continous spectrum.
Characteristic X-ray spectrum.
Filtreation of the beam.
Angular distribution of X-rays, Heel effect.

The X-ray tube
The Coolidge tube, cathode structure, filament, focusing cup, anode structure, fixed and rotating anode.
Thermal, electronic, optical focal spot.
Tubes with the grid.
Anode curves family.
Anode heat capacity and thermal load curves.
The tube box. Inherent filtration, heat capability of the box.

The high voltage generators
Block diagram of an X-ray apparatus.
The transformer principle. Single phase self-righting generator.
The righting.
Half-wave and full-wave single phase generators.
Three-phase, six-phase and twelve-phase generators.
Capacitor discharge generator.
High frequency INVERTER generator.
The Feedback for high voltage and filament current stabilization.

Command Table
kV and mA and ms settings.
kV, ma, ms measurements.
Compensation circuitry.
Safety circuitry.
Automatic Exposure Control.
Techniques of exercise on the command table: free settings technique, two points technique, one point technique, automatic programmer.

Radiologic image formation
Attenuation of the X-rays, law of attenuation.
Linear attenuation coefficient.
Beam Quality and Half Value Layer.
Exposure and ionisation chamber.
Equivalent Energy of the beam.
Kerma and Absorbed Dose. Units of measurement.
Relative frequency of radiation-matter interaction.
Formation of the radiological image.

Quali-Quantitative analysis of the beam and Quality Insurance
Practical measurement of the quality of the beam by the HVL.
Average energy and equivalent energy of the beam and physical and technicians factors influencing her: kVp, filtration, the waveform of the High Voltage.
Intensity of the beam, photon Fluence and anode current.
Measurement of the Output and yeld of an RX-tube to RX. Physical, technical, and geometric  factors that affect the performance of an X-ray tube.
Measurement of the absorbed dose. Relationship between the exposure and absorbed Dose.
Effect of the distance from the focal spot. Geometric penumbra.
Measurements of the focal spot dimensions and geometric effects of distortion.
The Practical Peak Voltage (PPV).

Readings/Bibliography

0) Consumptive of Mathematical Analysis for the freshmen university:
complex numbers (numerical form and exponential)
Derivation and its meaning
Functions and graph of  functions
Riemann Integration and integral theorems

1) Lecture notes of the teacher
very complete, detailed, may be sufficient if the student attends assiduously the
Course and integrates with its personal notes.

2) Italian language, superficial for many aspects
Roberto Passariello - RADIOLOGY Elements of Technology
(third edition) Idelson-Gnocchi

3) English language, truly complete:
Jerrold T. Bushberg, J. Anthony Seibert - The Essential Physics of
Medical Imaging - (Second Edition) Lippincott Williams & Wilkins

Teaching methods

Frontal didactics.
We will stimulate the student to interact with the instructor by participating actively in the lesson
to improve the understanding of the subject.

Assessment methods

Oral examination at the end of the Course.

Teaching tools

Frontal didactics.

We will use a simulation program of the spectrum of the X-rays to facilitate the understanding of the subject.
The program, developed for research, will remain to the student as a working instrument.

Office hours

See the website of Giuseppe Baldazzi