Principles of Biomedical Imaging (UG)

Module aims

To explain how images of the human body can be obtained using different forms of penetrating radiation

To provide a detailed explanation of how the imaging modalities of CT, X-ray, magnetic resonance imaging (MRI), ultrasound, and optical imaging work

Learning outcomes

 Knowledge and Understanding

  • Be able to explain how medical images are obtained using radiation or waves that penetrate the body.
  • Be able to describe the equipment required for imaging using the key imaging modalities.

Intellectual Skills

  • Be able to analyse the imaging performance of a scanner.
  • Be able to calculate the resolution of a scanner.

Transferable Skills

  • Able to read and summarise from information sources.

Module syllabus

 X-ray imaging: Nature and generation of X-rays: electron interaction with matter, X-ray spectrum, characteristic X-rays. Interaction of X-rays with matter: attenuation and Beer’s law, effect of tissue density and photon energy.  Image formation, theoretical contrast, image mottle and geometric blurring. Beam hardening. Image quality: parameters and measurement.  Dose and Contrast/Noise. Equipment: Tube, Filters, anti-scatter grid, collimator. Computed Radiology, fluoroscopic/fluorographic imaging.  Safety. Standard radiological safety checks.

X-ray CT: Basic principle of CT. The central slice theorem, backprojection algorithm, choice of reconstruction filter. Scanning configurations and implementation: spiral CT. Image Quality parameters and  artefacts.

Ultrasonic Imaging: Ultrasound propagation in tissue, generation, piezo-electric effect, transducer construction. Beam patterns. Fresnel & Fraunhofer diffraction. Pulsed A-Mode systems. Envelope detection. TGC. B-Mode imaging. Scanning geometries: rectilinear, curvilinear., beam steering. B-mode processing. Dynamic range compression, scan conversion. Doppler shift. Continuous Wave Doppler. Pulsed Doppler. Aliasing.

Magnetic resonance Imaging: NMR signals, gyromagnetic ratio, spin populations. Types of magnets, block diagram of MR systems, field strengths, radiofrequency and gradient coils. T1 and T2 time constants, free induction decay, spin dephasing, T2*. Basic pulse sequences: saturation recovery, inversion recovery, spin-echo; contrast mechanisms. Imaging: gradients, slice selection, frequency and phase-encoding, FOV, scan-time, multiple slices, k-space. Image Artefacts,.. MR Safety I: Projectile effect, implants, controlled areas, gradients and acoustic noise, RF Heating, SAR and local heating.

Optical imaging: Interaction of light with tissue, Microscopy, Confocal Microscopy, Fluorescence imaging, , Minimally Invasive Surgery, Endoscopy.


 Students must be able to perform basic algebra. Students must be familiar with Fourier Transforms.

Teaching methods

 Lectures: 18 hours
Study groups: 10 hours


●  Written exam: ; 90% weighting

Rubrics: 4 sections (Ultrasound, X-ray/CT, optical imaging, MRI), 100 points total Section 1: Ultrasound - 25 points (10 points multiple choice questions, 15 points free response questions) Section 2: X-ray/CT - 25 points (10 points multiple choice questions, 15 points free response questions) Section 3: Optical Imaging - 25 points (10 points multiple choice questions, 15 points free response questions) Section 4: Magnetic Resonance Imaging (MRI) - 25 points (10 points multiple choice questions, 15 points free response questions)

Outline answers to past papers will be available

●  Progress test: Progress test; 10% weighting; Multiple Choice Progress Test completed via Blackboard. 10%

Feedback : Full model answers are given for problem sheets the week after setting. Oral feedback is given in the study groups.