Assessment of computational tools for MRI RF dosimetry by comparison with measurements on a laboratory phantom
| Autor: | M. Borsero, Oriano Bottauscio, Domenico Giordano, Antonino M. Cassarà, Mario Chiampi, Luca Zilberti, Jeffrey Hand, Gerd Weidemann |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Electromagnetic field
Radio Waves computational modelling dosimetry MRI near field measurements Acoustics Imaging phantom Electromagnetic Fields Nuclear magnetic resonance Humans Dosimetry Radiology Nuclear Medicine and imaging Radiometry Boundary element method Physics Radiological and Ultrasound Technology Phantoms Imaging Finite-difference time-domain method Reproducibility of Results Magnetic Resonance Imaging Finite element method Magnetic field Amplitude Software |
| Zdroj: | Physics in Medicine and Biology. 60:5655-5680 |
| ISSN: | 1361-6560 0031-9155 |
| Popis: | This paper presents an extended comparison between numerical simulations using the different computational tools employed nowadays in electromagnetic dosimetry and measurements of radiofrequency (RF) electromagnetic field distributions in phantoms with tissue-simulating liquids at 64 MHz, 128 MHz and 300 MHz, adopting a customized experimental setup. The aim is to quantify the overall reliability and accuracy of RF dosimetry approaches at frequencies in use in magnetic resonance imaging transmit coils. Measurements are compared against four common techniques used for electromagnetic simulations, i.e. the finite difference time domain (FDTD), the finite integration technique (FIT), the boundary element method (BEM) and the hybrid finite element method-boundary element method (FEM-BEM) approaches. It is shown that FDTD and FIT produce similar results, which generally are also in good agreement with those of FEM-BEM. On the contrary, BEM seems to perform less well than the other methods and shows numerical convergence problems in presence of metallic objects. Maximum uncertainties of about 30% (coverage factor k = 2) can be attributed to measurements regarding electric and magnetic field amplitudes. Discrepancies between simulations and experiments are found to be in the range from 10% to 30%. These values confirm other previously published results of experimental validations performed on a limited set of data and define the accuracy of our measurement setup. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|