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

Summary, in English

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.

• Författare: Johan Olsrud; Ronnie Wirestam; Sara Brockstedt; Annika M K Nilsson; Karl-Göran Tranberg; Freddy Ståhlberg; Bertil R Persson
• Avdelning/ar: Diagnostisk radiologi, Lund; Medicinsk strålningsfysik, Lund; Kirurgi, Lund
• Publiceringsår: 1998
• Språk: Engelska
• Sidor: 2597-2613
• Publikation/Tidskrift/Serie: Physics in Medicine and Biology
• Volym: 43
• Issue: 9
• Fulltext: - 509 kB; Download statistics
• Länkar: http://www.iop.org/EJ/article/0031-9155/43/9/012/m80912.pdf
• Dokumenttyp: Artikel i tidskrift
• Förlag: IOP Publishing
• Ämne: Radiology, Nuclear Medicine and Medical Imaging
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 1361-6560