Related Links
  • Diagnostic Radiology Physics: A Handbook for Teachers and Students, 2014 (IAEA)
  • Bushberg, J.T., Seibert J.A., Leidholdt E.M. and Boone, J.M., The Essential Physics of Medical Imaging. Third Edition, Lippincott, Williams and Wilkins, Baltimore, MD (2012)ISBN 9780781780575
  • Ter Haar, G., Duck, F.A., The Safe Use of Ultrasound in Medical Diagnosis.  British Institute of Radiology, London (2000) ISBN 9780905749785
  • Hedrick, W.R., Hykes, D.L., Starchman, D.E., Ultrasound Physics and Instrumentation, Mosby, St. Louis, Mo (2004) ISBN 9780323032124
  • Kremkau, F.W., Diagnostic Ultrasound: Principles and Instruments, Saunders, Philadelphia, Pennsylvania (2005). ISBN 9780721631929

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Ultrasound has become an almost ubiquitous imaging tool. It is used for anatomical imaging, quantitation of flow (especially in cardiology), imaging in the emergency room with small handheld units, in surgery, and in many areas of the clinic and hospital, without and with contrast media. It is capable of two-, three-, and even four-dimensional imaging using sophisticated transducer arrays. It is also widely used in veterinary medicine.  However, it receives minimal attention in terms of medical physics support and quality control since it uses non-ionizing radiation.

Important Principles

The medical physicist must be familiar with ultrasound imaging and all of the factors affecting image quality, including the myriad adjustments possible by the ultrasound technologist during the examination and how these impact the final image. The bioeffects and safety aspects of ultrasound must also be understood.

Artefacts are much more prevalent in ultrasound imaging than in other areas of medical imaging. The medical physicist must be able to investigate and identify causes of artefacts and to undertake routine quality control tests of ultrasound imaging systems, including systems used for recording of the images.

The primary sophistication in ultrasound imaging is associated with the transducers and imaging techniques. These range from single element transducers with continuous or pulsed operation, one-dimensional arrays, multi-frequency operation, apodization and dynamic aperture techniques, harmonic imaging, Doppler measurements, spectral analysis, and contrast agents.

It is important to be able to measure acoustic output, slice thickness, resolution, system sensitivity, image uniformity, depth penetration, distance accuracy, low contrast detectability, ring-down, and flow accuracy.

Introduction to References

There are several books available on the basics of ultrasound physics including Kremkau and Hedrick.  The text by Bushberg, et al., is a good resource for the physics and imaging.  The NCRP (1983, 1991, 2002) and AAPM reports (rpt 65, rpt 128) in the Supplemental References provide excellent details on specific topics and are highly recommended.