title: Visualization and registration of three-dimensional E-field distributions in annual-phased-array applicators.
abstract: A testing system is presented allowing registration, digitization, and evaluation of three-dimensional power distributions rendered by annular-phased-array applicators in homogeneous liquid media. The system is based on a lamp phantom originally developed to visualize power distributions. Now the brightness distribution is registered via a charge-coupled device camera and transferred to a PC-based evaluation system outside the shielding room. An appropriate mechanical coupling of camera and sensor matrix probing the phantom was built in order to keep optical image conditions constant under movement. For visualization and evaluation commercially customized software was employed. The evaluation of the system shows the linearity between sensor signal and power density magnitude to be sufficient for evaluation and graphical representation of three-dimensional data sets. In a first practical application the testing system was employed to evaluate dependencies of power distributions as a function of frequency and phase settings on temperatures and, subsequently, the relevance of those results for clinical hyperthermia in a SIGMA-60 applicator (BSD-2000 system). Now, the system is ready to evaluate more complex multiantenna array applicators like the SIGMA-Eye applicator. The measuring system is particularly suitable for a fast comparison of APA applicators applied for a homogeneous medium. Implications for heterogeneous structures (like in patients) are then possible via modeling calculations.
authors.affiliation: Clinic for Radiation Medicine, Charité, Medical School of Humboldt University at Berlin, Germany. peter.wust@charite.de
authors.forename: P
authors.initials: P
authors.lastname: Wust
authors.forename: H
authors.initials: H
authors.lastname: Fähling
authors.forename: M
authors.initials: M
authors.lastname: Brünner
authors.forename: J
authors.initials: J
authors.lastname: Nadobny
authors.forename: A
authors.initials: A
authors.lastname: Jordan
authors.forename: R
authors.initials: R
authors.lastname: Felix
mesh_terms: D002138:Calibration; D006801:Humans; D006979:Hyperthermia, Induced; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D008905:Minicomputers; D019047:Phantoms, Imaging; D011846:Radio Waves; D012965:Sodium Chloride; D012996:Solutions
chemical_list: D012996:Solutions; D012965:Sodium Chloride