TY - JOUR
T1 - Hyperthermia MRI temperature measurement
T2 - Evaluation of measurement stabilisation strategies for extremity and breast tumours
AU - Wyatt, Cory
AU - Soher, Brian
AU - MacCarini, Paolo
AU - Charles, H. Cecil
AU - Stauffer, Paul
AU - MacFall, James
N1 - Funding Information:
The authors wish to thank Kevin Kelley, Jerry Dahlke, Daniel Martins, Sneha Rangarao, and Kavitha Arunachalam for help with performing the experiments. We would also like to thank Omar Arabe and Vadim Stakhursky for helping build the applicators used in the experiments. Additionally, we acknowledge NCI grant PO1-CA042745 and NIH grant T32-EB001040 for supporting this research.
PY - 2009
Y1 - 2009
N2 - Purpose: MR thermometry using the proton resonance frequency shift (PRFS) method has been used to measure temperature changes during clinical hyperthermia treatment. However, frequency drift of the MRI system can add large errors to the measured temperature change. These drifts can be measured and corrected using oil references placed around the treatment region. In this study, the number and position of four or more oil references were investigated to obtain a practical approach to correct frequency drift during PRFS thermometry in phantoms and in vivo. Materials and methods: Experiments were performed in a 140 MHz four antenna mini-annular phased array (MAPA) heat applicator (for treatment of extremity tumours) and an applicator for heating of the breast, with symmetric and asymmetric positioning of the oil references, respectively. Temperature change PRFS images were obtained during an hour or more of measurement with no application of heat. Afterwards, errors in calculating temperature change due to system drift were quantified with and without various oil reference correction arrangements. Results: Results showed good temperature correction in phantoms and in a human leg, with average errors of 0.28°C and 0.94°C respectively. There was further improvement in the leg when using eight or more oil references, reducing the average error to 0.44°C, while the phantoms showed no significant improvement. Conclusions: These results indicate that oil reference correction performs well in vivo, and that eight references can improve the correction by up to 0.5°C compared to four references.
AB - Purpose: MR thermometry using the proton resonance frequency shift (PRFS) method has been used to measure temperature changes during clinical hyperthermia treatment. However, frequency drift of the MRI system can add large errors to the measured temperature change. These drifts can be measured and corrected using oil references placed around the treatment region. In this study, the number and position of four or more oil references were investigated to obtain a practical approach to correct frequency drift during PRFS thermometry in phantoms and in vivo. Materials and methods: Experiments were performed in a 140 MHz four antenna mini-annular phased array (MAPA) heat applicator (for treatment of extremity tumours) and an applicator for heating of the breast, with symmetric and asymmetric positioning of the oil references, respectively. Temperature change PRFS images were obtained during an hour or more of measurement with no application of heat. Afterwards, errors in calculating temperature change due to system drift were quantified with and without various oil reference correction arrangements. Results: Results showed good temperature correction in phantoms and in a human leg, with average errors of 0.28°C and 0.94°C respectively. There was further improvement in the leg when using eight or more oil references, reducing the average error to 0.44°C, while the phantoms showed no significant improvement. Conclusions: These results indicate that oil reference correction performs well in vivo, and that eight references can improve the correction by up to 0.5°C compared to four references.
KW - MR frequency drift
KW - Magnetic resonance temperature imaging (MRTI)
KW - Non-invasive thermometry
KW - Oil reference correction
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U2 - 10.1080/02656730903133762
DO - 10.1080/02656730903133762
M3 - Article
C2 - 19925322
AN - SCOPUS:70350709363
SN - 0265-6736
VL - 25
SP - 422
EP - 433
JO - International Journal of Hyperthermia
JF - International Journal of Hyperthermia
IS - 6
ER -