Introduction to biomedical imaging

This course introduces the fundamental principles of biomedical imaging and provides an overview of the major imaging modalities used in medicine and biological research. The primary focus is on understanding the physical principles underlying each imaging technique, the mechanisms of image formation, and their biomedical and clinical applications.

The course covers Ultrasound (US) Imaging, X-ray Imaging, Computed Tomography (CT), Nuclear Medicine (PET/SPECT), and Magnetic Resonance Imaging (MRI). For each modality, students will learn how signals are generated and detected, how images are reconstructed and interpreted, and how image quality is influenced by factors such as resolution, contrast, and noise.

By comparing the strengths, limitations, and applications of different imaging modalities, students gain a foundation for selecting and evaluating appropriate imaging techniques for specific biomedical and clinical problems.

The course follows the outline below:
1. Introduction to biomedical imaging: its historical development, and parameters for evaluating image quality. Visit of Lausanne University Hospital (CHUV)
2. Ultrasound imaging: basic characteristics of sound wave, US transducer, ultrasound and tissue interaction, doppler effect
3. X-ray imaging I: electromagnetic radiation, X-ray production, interaction of X-ray with matter
4. X-ray imaging II: attenuation, detection and radiation protection
5. Computed tomography:  from projection to image
6. Emission computed tomography:  what are tracers and how to "trace" them in your body, gamma-ray detection
7. Positron emission tomography (PET):  positron annihilation, coincidence detection
8. Introduction to magnetic resonance (MR): scanner components, Boltzmann distribution, from spins to magnetization, motion of magnetization
9. Relaxation of nuclear magnetization: excitation of spins, relaxation, the basis of MR contrast, equation of motion
10. Echo formation and spatial encoding: principles of MR image formation, k-space, echo formation
11. Basic MRI contrast mechanisms: T2* weighted MRI, biophysical basis of fMRI, Spin-echo imaging sequence, T1, T2, proton-density, contrast agents
12. MR spectroscopy: In vivo biochemistry, chemical shift, J-coupling, localization
13. MRI in action: hands-on MRI scanner session at CHUV
14. Overview of imaging modalities: advanced contrasts (phase-contrast, diffusion), hybrid imaging (PET-MRI), comparison of imaging modalities