93913 - Bioelectromagnetism

Learning outcomes

The students, will first learn the main phenomena related to the propagation of RF electromagnetic waves in free space, in real channels and in guided structures and will learn how they interact with materials. The budget in terms of exchanged electromagnetic energy is deeply analyzed and related with different fields of interest for biomedical applications such as energy and data transmission, for telemetry purposes and heat conversion for therapy applications. These competences will allow the students to be instructed on: - the main phenomena of the propagation electromagnetic fields. - mechanisms of interaction of electromagnetic fields with different material means for different working frequencies. - mechanisms of interaction between electromagnetic fields and biological systems: dispersive behavior. - design and characterization of simple antenna elements. - elementary principles of the dosimetry of electromagnetic fields.

Course contents

The course aims to provide students with the knowledge to understand the interaction between electromagnetic fields and material means, in particular biological tissues, and how these are the basic mechanisms for different applications of bioengineering.

The first part will introduce the fundamental laws of electromagnetism, the concept of uniform plane waves and the laws of propagation in homogeneous and non-homogeneous materials and their characterization through EM propagation.

The dispersive materials will then be introduced and the mechanisms of material polarization  and the related frequencies at which these phenomena occur will be explained.

In the second part of the course, the study of Nuclear Magnetic Resonance techniques and apparatuses will be deepened. Students will thus be able to see applications of different concepts of electromagnetism, starting from static fields up to VHF band frequencies.

Subsequently, the notions of far-field, antenna and characteristic quantities of radiation will be dealt with to provide students with the fundamental concepts of radiofrequency and microwave dosimetry and telemetry techniques.

Finally, the concepts of circuit with lumped and distributed  elements will be compared, as a basis for the modeling of the phenomena of bioelectricity and the transmission of electrical signals in the human body.

There are some software laboratory activities in which students will practice electromagnetic simulation and build simple models to characterize the interaction between electromagnetic fields and biological tissues. The topics covered in groups and the expected times for each group are described in detail below.

INTRODUCTION (2)
Bioelectromagnetism, bioelectricity, bioelectromagnetics.
Classification of EM fields and mechanisms of interaction with different media.
BASIC ELECTROMAGNETISM (24)
Electromagnetic fields in the time domain:
- Maxwell's equations.
- Material means and constitutive relationships.
- Discontinuity.
- Conservation laws.

Sinusoidal electromagnetic fields:
- Maxwell's equations.
- Poynting's theorem and other fundamental theorems.
- Polarization of the electromagnetic field.
- Dielectric means.
- Means conductors.

Uniform plane waves:
- Equations and general characteristics.
- Propagation in the media.
- Reflection and transmission.
- Propagation of plane waves through one layer and several layers.


NUCLEAR MAGNETIC RESONANCE (16)

Operating principles
Fundamental equations of the MRI
Structure of an MRI system.
Static field B0 and main magnet.
Gradient field and design methods for low frequency fields.
Radio-frequency field B1: circuit analysis.

ANTENNAS and DOSIMETRY (12)
Elementary sources.
Extensive sources.
Characteristic quantities of radiation.
Antenna arrays.
Dosimetry .

CIRCUITS and SIGNAL TRANSMISSION (6)
Circuits with concentrated constants.
Circuits with distributed constants.
Transmission lines and modeling of biological phenomena.

Readings/Bibliography

1) Perregrini, Conciauro Fondamenti di onde elettromagnetiche – Mc Graw Ill

2) Electromagnetic analysis and design in magnetic resonance imaging / Jianming Jin

Teaching methods

power point presentations; sessions to verify the understanding of the topics through group work; lessons given by the students with teach back methods.

Assessment methods

Learning verification takes place through an oral test preceded by a written one in which the student is invited to prepare an answers schematic for three questions related to the courseprogram. During this test, the use of books, notes, calculators, electronic media is not allowed.

The written test aims to verify the skills acquired in highlighting the fundamental aspects of the topics dealt with and to solve problems in the context of the topics addressed. The oral test follows the written one and aims to deepen the verification of the acquisition of knowledge required by the course program. The final mark is expressed in thirtieths and takes into account the results obtained in both tests.

Teaching tools

Personal computer, Cadence AWR, CST Microwave studio

Office hours

See the website of Alessandra Costanzo