Adaptation of antenna profiles for control of MR guided hyperthermia (HT) in a hybrid MR-HT system
- Clinic for Radiation Oncology, Charite-Universitaetsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany)
A combined numerical-experimental iterative procedure, based on the Gauss-Newton algorithm, has been developed for control of magnetic resonance (MR)-guided hyperthermia (HT) applications in a hybrid MR-HT system BSD 2000 3D-MRI. In this MR-HT system, composed of a 3-D HT applicator Sigma-Eye placed inside a tunnel-type MR tomograph Siemens MAGNETOM Symphony (1.5 T), the temperature rise due to the HT radiation can be measured on-line in three dimensions by use of the proton resonance frequency shift (PRFS) method. The basic idea of our iterative procedure is the improvement of the system's characterization by a step-by-step modification of the theoretical HT antenna profiles (electric fields radiated by single antennas). The adaptation of antenna profiles is efficient if the initial estimates are radiation fields calculated from a good a priori electromagnetic model. Throughout the iterative procedure, the calculated antenna fields (FDTD) are step-by-step modified by comparing the calculated and experimental data, the latter obtained using the PRFS method. The procedure has been experimentally tested on homogeneous and inhomogeneous phantoms. It is shown that only few comparison steps are necessary for obtaining a dramatic improvement of the general predictability and quality of the specific absorption rate (SAR) inside the MR-HT hybrid system.
- OSTI ID:
- 21032879
- Journal Information:
- Medical Physics, Vol. 34, Issue 12; Other Information: DOI: 10.1118/1.2804617; (c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetic Resonance–Guided High-Intensity Focused Ultrasound Hyperthermia for Recurrent Rectal Cancer: MR Thermometry Evaluation and Preclinical Validation
Accuracy of real time noninvasive temperature measurements using magnetic resonance thermal imaging in patients treated for high grade extremity soft tissue sarcomas