MRI thermometry in phantoms by use of the proton resonance frequency shift method: application to interstitial laser thermotherapy

Phys Med Biol. 1998 Sep;43(9):2597-613. doi: 10.1088/0031-9155/43/9/012.


In this work the temperature dependence of the proton resonance frequency was assessed in agarose gel with a high melting temperature (95 degrees C) and in porcine liver in vitro at temperatures relevant to thermotherapy (25-80 degrees C). Furthermore, an optically tissue-like agarose gel phantom was developed and evaluated for use in MRI. The phantom was used to visualize temperature distributions from a diffusing laser fibre by means of the proton resonance frequency shift method. An approximately linear relationship (0.0085 ppm degrees C(-1)) between proton resonance frequency shift and temperature change was found for agarose gel, whereas deviations from a linear relationship were observed for porcine liver. The optically tissue-like agarose gel allowed reliable MRI temperature monitoring, and the MR relaxation times (T1 and T2) and the optical properties were found to be independently alterable. Temperature distributions around a diffusing laser fibre, during irradiation and subsequent cooling, were assessed with high spatial resolution (voxel size = 4.3 mm3) and with random uncertainties ranging from 0.3 degrees C to 1.4 degrees C (1 SD) with a 40 s scan time.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Gels
  • Hyperthermia, Induced / methods*
  • In Vitro Techniques
  • Laser Therapy*
  • Liver
  • Magnetic Resonance Imaging / instrumentation
  • Magnetic Resonance Imaging / methods*
  • Magnetic Resonance Imaging / statistics & numerical data
  • Models, Theoretical
  • Optics and Photonics
  • Phantoms, Imaging
  • Sepharose
  • Swine
  • Temperature
  • Thermometers*


  • Gels
  • Sepharose