SAR analysis of the improved resonant cavity applicator by a 3-D FEM

Abstract

This paper discusses the improvement of the reentrant resonant cavity applicator, such as an electromagnetic shield and water bolus for concentrating heating energy on deep tumors in an abdominal region of a human body.

In our previous study, it was found that undesirable areas such as a neck, arm, hip and breast were heated when heating the abdomen with the developed applicator.

Therefore, we have improved the resonant cavity applicator to overcome this problem. First, a cylindrical shield made of an aluminum alloy was installed inside the cavity. It was designed to protect non-tumorous areas from concentrated electromagnetic fields. Second, in order to concentrate heating energy on deep tumors inside the human body, a water bolus was installed around the human body surface.

In this study, to evaluate the effectiveness of the proposed methods, specific absorption rate (SAR) distributions were calculated by FEM with the 3-D anatomical human body model reconstructed from MRI images.

From these results, it was confirmed that the improved heating system was effective to non-invasively heat abdominal deep tumors.