MPHY3891/M891: Medical Imaging with Non-ionising Radiation

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Course information

Unit value
Year of study
Term
Course organiser
Second examiners
0.5
3 or 4
Term 2
Dr Ben Cox
Prof Paul Beard and Dr Karin Shmueli

Purpose

The course forms part of the Medical Physics undergraduate degrees (B.Sc., B.Sc.(Intercal) and M.Sci.) and Electronic Engineering with Medical Electronics degree (B.Eng.). It is an optional course for the B.Sc. and B.Eng. and compulsory for the B.Sc.(Intercal) and M.Sci. The purpose of this course is to provide an introduction to the two important areas of medical imaging which do not use ionising radiation, namely Ultrasound and Magnetic Resonance Imaging (MRI). This also complements course MPHY3890 which covers Medical Imaging with Ionising Radiation.

Year 3 and M-level variants

This course can be taken in Year 3 as MPHY3891 or in Year 4 as an M-level variant called MPHYM891. The two variants differ in the amount of coursework, and the pass mark for the M-level variant is 50%.

Aims and Objectives

The course aims to provide a foundation for students wishing to either pursue these subjects for research or the development of clinical or industrial applications, or to learn more about Medical Physics and imaging science in general. The latter reason is particularly relevant to our intercalated medical students. The course aims to present the subject with as much physical science content as possible whilst still being of great practical relevance. The development of these expensive and highly technical machines has propelled Medical Physics to the forefront of applied science, and this course is an important part of the Departments teaching effort to provide a full education in this subject. The course is attended most years by several clinicians and new research students from other Departments in UCL that are involved in MRI research (after permission from Prof. Ordidge), since it has been recognised as a good introduction to MRI research.

Objectives

  • To impart knowledge and understanding on the basic physical principles of Magnetic Resonance Imaging and Ultrasound Imaging.
  • To impart knowledge on the clinical applications of these imaging techniques and the processes involved in the generation of useful images.
  • To impart knowledge and understanding on the instrumentation used by these imaging techniques.
  • To impart knowledge and understanding on the biological hazards, safe levels and methods of measurement of ultrasound, radiofrequency and magnetic fields.

Teaching and exams

Teaching, during Term 2, will consist of:

  • Lectures (32 hours).
  • Required written work (essays, problem sheets), 25 hours.
  • Private reading, 32 hours.

The assessment will consist of:

  • Unseen written examination (3 hours) worth 80% of the total course mark.
  • Problem Sheets completed during term-time worth 20% of the total course mark.

Prerequisites

We assume that you have met the minimum entry requirements for our undergraduate degree programmes (i.e. A level Mathematics (grade A preferred), Physics and one other A level at ABB or above, or equivalent). If you feel you meet the prerequisites through a non-standard route, please contact the module organiser. All variants of the modules have the same prerequisites.

Specific knowledge assumed:

Mathematics: Familiarity with simple algebra, trigonometry, basic differential and integral calculus, exponentials, vectors, complex numbers and vector calculus notation would be helpful.

Physics / Engineering: No strict prerequisites but Newton’s laws, conservation laws, some basic classical rotational mechanics, the Boltzmann distribution and a few quantum mechanical concepts will be used during the module.

Biology: No specific background knowledge required.

Other: Nothing specific.

Description

The syllabus is designed to teach students the physical principles of each method followed by the instrumentation, the advantages and disadvantages of these technologies, their applications in medicine, the relevant safety limits and considerations associated with each technique, and concluding with applications in cutting edge research. Mathematics is used appropriately and extra tuition is provided to intercalated medical students as necessary.
The strong physical science content makes the course popular with 3rd year physics students, whilst the applicability to medicine has resulted in the course being popular with 3rd year intercalated medical students. The 3rd year Physics students find the course interesting and challenging.

Brief Syllabus

Part 1a: Acoustics of Ultrasound Imaging

  1. Introduction (1 hour)Brief history of ultrasound imaging, waves, acoustics basics, wavelength, frequency, acoustic pressure.
  2. Acoustic wave equation (1 hour)Equation of state, conservation of mass, conservation of momentum, linear wave equation.
  3. Plane waves (1 hour)Acoustic energy, power, intensity, solutions to the 1D wave equation, single-frequency plane waves, spherical and cylindrical waves.
  4. Scattering and absorption (1 hour) Acoustic impedance, reflection, refraction, Snell's law, scattering, acoustic attenuation, absorption,time-gain compensation.
  5. Nonlinear acoustics (1 hour) Material nonlinearity, convective nonlinearity, nonlinear propagation, wave steepening, harmonic generation, shock parameter, tissue harmonic imaging.
  6. Bubbles and bioeffects (1 hour) Ultrasound contrast agents, cavitation, radiation force, streaming, bioeffects, safety, mechanical and thermal indices.
  7. Therapeutic ultrasound (1 hour) Lithotripsy, high intensity focussed ultrasound, fracture healing, sonophoresis.

Part 1b: Ultrasound imaging: Instrumentation and Clinical Aspects

  1. Ultrasound transducers: piezoelectric generation and detection of ultrasound, piezoelectric materials, transducer frequency response, quarter-wave matching layers, focused and planar transducer beam patterns, reciprocity principle. [2 hours]
  2. Principles of imaging: image formation, time gain compensation, A, B and M imaging modes. [1 hour]
  3. Imaging instrumentation: B-mode scanners, linear arrays, electronic transmit and receive focusing, phased arrays, contrast, spatial resolution, image artefacts. [2 hours]
  4. Doppler ultrasound: haemodynamics, the Doppler equation, CW and pulsed Doppler, demodulation techniques, colour Doppler, power Doppler [1 hours]
  5. Clinical applications of diagnostic ultrasound: obstetrics, abdomen, cardiovascular, breast, eye [1 hour]
  6. Hybrid optical-ultrasound imaging modalites: photoacoustic imaging, ultrasound modulated optical tomography [1 hour]


Part 2: Magnetic Resonance Imaging (MRI)

  1. Basic NMR Theory (3 hours)Nuclear Magnetic Moments, Bloch Equations, Relaxation
  2. NMR Signal Acquisition (2 hours)Continuous Wave NMR, Pulsed NMR, Fourier Transform NMR
  3. Basic MR Imaging Theory (1.5 hours)Spatial Encoding Using Gradients, Image Formation Using Fourier Transforms, Two Dimensional Fourier Transform Imaging, Slice selection procedure.
  4. NMR Hardware (1.5 hours)NMR Spectrometer Design, Magnets - Design, Shimming, Shielding, Gradients and Radiofrequency Coils.
  5. Tissue Parameters and Contrast in Imaging (3 hours)Relaxation Mechanisms, Proton Density, T1, T2, Sequence Dependence of Contrast, Spin Echo, Multiple Echo, Inversion Recovery.
  6. Advance Imaging Sequences (2 hours)Multi-slice Imaging, Gradient Echo imaging (FLASH), K space Formulation of Imaging Sequences, Echo Planar Imaging.
  7. Advanced Image Contrast Mechanisms (2 hour) Contrast Agents, Flow and Angiography, Diffusion and Perfusion, Blood Oxygenation and MTC, Image processing.
  8. NMR Safety (1 hour)Static Field Hazards, Varying Magnetic Field Hazards, RF Power Deposition Hazards.

Additional Reading

  • T.L. Szabo, Diagnostic Ultrasound Imaging: Inside Out, Elsevier, 2004.
  • L.E. Kinsler, A. R. Frey, A.B. Coppens, and J.V. Sanders,Fundamentals of Acoustics, 4th Edition, Wiley, 2000.
  • W. R. Hedrick, D. L. Hykes, and D. E. Starchman, Ultrasound Physics and Instrumentation, Mosby-Year Book: St. Louis. Third Edition 1995. ISBN 0-8151-4246-3 (JH)
  • Hoskins PR, Thrush A, Martin K, Whittingham TA, Diagnostic Ultrasound: Physics and Equipment, GMM, 2003
  • CR Hill, JC Bamber, G.R ter Haar Physical Principles of Medical Ultrasonics
  • Evans DH, McDicken WN, Doppler Ultrasound: Physics, instrumentation and signal processing, (2nd ed). Chichester, Wiley 2000
  • A short history of ultrasound imaging: http://www.ob-ultrasound.net/history1.html
  • P. Fish, Physics and Instrumentation of Diagnostic Medical Ultrasound, John Wiley & Sons: Chichester, 1992. ISBN 0-471-92651-5.
  • D. W. McRobbie, E. A. Moore, M. J. Graves and Prince, M.R. MRI From Picture to Proton, Cambridge 2003
  • M. Flower (Editor), Webb's Physics of Medical Imaging, CRC Press, 2012.
  • M. A. Brown and R. C. Semelka, MRI Basic Principles and Applications, Wiley-Liss, Inc. Second Edition 1999. ISBN 0-471-33062-0
  • H. Schild, MRI made easy, Schering, 1990.