Multilayer conformal applicator for microwave heating and brachytherapy treatment of superficial tissue disease

Abstract

CT scans of the applicator confirmed that the applicator conforms well to complex body contours and should maintain good conformity and positional stability even when worn on a mobile patient. Thermometry testing of two different waterbolus geometries demonstrated that uniform circulation and temperature control can be maintained throughout large, complex bolus shapes.

Quality assurance guidelines for superficial hyperthermia clinical trials

“…An optimal contact area of the water bolus with the skin of the target surface requires that the bolus is sufficiently large to smoothly follow the skin contour [37–40] and that the bolus extends beyond the radiating aperture. This provides better coupling of EM/US field to tissue without distorting the radiation pattern; at the same time it puts greater demands on reproducible alignment of the applicator relative to the tumor margin.…”

Magnetic Resonance-Guided Drug Delivery

“…In general, hyperthermia can be divided into mild (~40° −45° C) and ablative (~50° −100° C) regimes in which bioeffects are governed by a time-temperature Arrhenius continuum (thermal dose). Commonly used methods for generating local hyperthermia include the use of radiofrequency, 20 microwaves, 21 laser, 22 or superficial hot water applicators. 23 Temperature-sensitive DDS can be used as an adjuvant to thermal ablation to reduce the potential for tumor regrowth in regions of sublethal thermal damage such as at the ablation margin.…”

Performance evaluation of a conformal thermal monitoring sheet sensor array for measurement of surface temperature distributions during superficial hyperthermia treatments

“…The conformity (and thermal contact) to the realistically shaped human torso model in Figure 3 is excellent with the TMS bending smoothly both around the side, under the arm, and simultaneously twisting in the axial direction to fit the complex surface contour. When integrated into the multilayered CMA applicator [17,27], the conformal TMS array can maintain fixed sensor placement relative to the individual heating elements regardless of patient movements during a typical hour long hyperthermia treatment.…”

“…Another approach that has been used successfully in the clinic involves computer controlled mechanical rotation of one or two scanning spiral microstrip antennas over surface disease [15]. The largest surface applicators used clinically to date are the 25 aperture 915 MHz spiral microstrip array developed at Stanford University [16] and the conformal microwave array (CMA) applicator [1,17,18]. Other multi-element array applicators have been developed that should be available in the hyperthermia clinic soon [19].…”