A Family Jewel- Dual Energy CT with Gemstone

What is it? How does it work?


Dual energy CT scanning is a non-invasive imaging technique utilising dual energy at the same site, thereby distinguishing distinct materials based on their differing attenuation properties. This allows for material based or ‘spectral imaging’ instead of the conventional attenuation based imaging.

There are a number of dual energy CT units on the market, with the GE Discovery 750HD CT unit available at Spectrum Medical Imaging Liverpool. This unit uses a single X-ray tube with fast kV switching between 80 and 140 kVp with 0.4 ms interval[1] focused at the tissues of interest. Then the gemstone detector, with a slice thickness of 0.625mm, utilises gemstone scintillator materials allowing for fast sampling, low afterglow, and high light output. Following acquisition, the data is calibrated with ability to adjust contrast enhancement and create iodine map images.

What are the benefits over conventional CT?

  • Decreased ionising radiation dose
  • Faster scan times
  • Reduced beam hardening effects
    • Useful for metal prosthesis
  • Improved images
    • Multiple imaging planes
    • 3D reconstruction
    • Material differentiation & quantification
  • Multisystem applications




What are the clinical applications?


Dual Energy CT has widespread applications including:

  • Cardiovascular imaging
  • Oncological detection and monitoring[4]
  • Renal stones[1]
  • Pulmonary embolism[5]
  • Abdominal imaging[6]
  • Musculoskeletal imaging[7]


1. Krasnicki, T., et al., Novel clinical applications of dual energy computed tomography. Adv Clin Exp Med, 2012. 21(6): p. 831-41.

2. Halliburton, S., et al., State-of-the-art in CT hardware and scan modes for cardiovascular CT. J Cardiovasc Comput Tomogr, 2012. 6(3): p. 154-63.

3. Vliegenthart, R., et al., Dual-energy CT of the heart. AJR Am J Roentgenol, 2012. 199(5 Suppl): p. S54-63.

4. De Cecco, C.N., et al., Dual-energy CT: oncologic applications. AJR Am J Roentgenol, 2012. 199(5 Suppl): p. S98-S105.

5. Zhang, L.J., et al., Dual-energy CT lung ventilation/perfusion imaging for diagnosing pulmonary embolism. Eur Radiol, 2013. 23(10): p. 2666-75.

6. Morgan, D.E., Dual-energy CT of the abdomen. Abdom Imaging, 2013.

7. Nicolaou, S., et al., Dual-energy CT: a promising new technique for assessment of the musculoskeletal system. AJR Am J Roentgenol, 2012. 199(5 Suppl): p. S78-86.