Characterization of the SAR-distribution of the Sigma-60 applicator for regional hyperthermia using a Schottky diode sheet

Abstract

The SAR distributions of the Sigma-60 applicator are in good agreement with theoretically expected values. The flexible Schottky diode sheet proves to be an excellent tool to make accurate, quantitative measurements of E-field distributions at low (25 W) and medium (400 W) power levels. An important feature of the SDS is that it enables one to significantly improve quantitative quality assurance procedures and to start quantitative comparisons of the performance of the different deep hyperthermia systems used by the various hyperthermia groups.

Electromagnetic Head-And-Neck Hyperthermia Applicator: Experimental Phantom Verification and FDTD Model

“…This difference might be due to thermal conduction, which result in an overestimation of the EFS by IR thermography. In radial direction this size is normally λ/3 [27] [13], which means ∼31mm in a muscle phantom, and correlates well with the values in this study. In axial direction this focus is determined by a combined effect of the distance between the antenna rings, the radius of the antenna rings, and the operating frequency [14], i.e.…”

“…Hereto, two sheets were positioned between both halves of the prototype ( Figure 3). To avoid a decrease in sensitivity caused by overlapping sheets at the location of the diodes [27], we used a distance between both sheets such that one row of measurement points was absent. SAR values can be calculated from the amplitude of the measured E-field values, using the effective conductivity (σ ef f ) and mass-density (ρ), according to:…”

Clinical implementation of hyperthermia treatment planning guided steering: A cross over trial to assess its current contribution to treatment quality

“…For all hyperthermia treatments in this study, the BSD2000-3D system (BSD Medical systems, Salt Lake City, UT) was used with the Sigma-60 applicator [21][22][23]. In Rotterdam, the standard operating frequency of the Sigma-60 is 77 MHz.…”

3D versus 2D steering in patient anatomies: A comparison using hyperthermia treatment planning

“…In most institutes, deep-seated tumours such as cervix uteri carcinoma are heated with loco-regional phased-array systems operating at frequencies in the range of 70-150 MHz [6,7]. The distribution of the absorbed power can be steered by varying the amplitude and the phase of the electric fields imposed by the individual antennas.…”