A phantom system for microwave treatment of intraocular tumors

A gel-block system was developed to illustrate heating patterns induced by ophthalmic microwave applicators. A heat-sensitive liquid crystal card was affixed as to bisect a Lucite box. The box was then filled with a clear tissue equivalent polyacrylamide gel. It was found that semicircular heating patterns were generated within the gel. These patterns were visualized by placing one of the dish-shaped ophthalmic microwave applicators on top of the polyacrylamide gel and the heat-sensitive liquid crystal card. An antenna was then placed in the gel and behind the card. Microwave energy was sent through the card and into the gel. This demonstrated the relatively homogeneous and roughly circular heating pattern produced at the applicator's surface. A combination of these profiles led to construction of a three-dimensional, domeshaped model of heating, as provided by this microwave antenna design.