齊藤 一幸

In recent years, various types of medical applications of microwave energy have widely been investigated and reported. We present a surgical device which employs the thermal effect produced by microwave energy. High power microwave energy can generate a coagulated region at the surface of the biological tissue such as organs. By coagulating organs, bleeding can be stopped. However, a microwave surgical device cannot cut the tissue without any device support, such as a blade. On the other hand, radio frequency (RF) current capable of cutting tissue without any support. This study presents a combination of a forceps type microwave surgical device combined with RF current for biological tissue cutting mechanism. Furthermore, ten sealed porcine blood vessels, sealed by the device, capability to withstand pressure were measured. Sealed blood vessels can withstand up to 200 mmHg of pressure and sufficient to withstand human blood pressure.

Recently, various electromagnetic (EM) applications have become common, and humans are frequently exposed to EM waves. Therefore, the effect of EM waves on the human body should be evaluated. In this study, we focused on the specific absorption rate (SAR) due to the EM waves emitted from a smartphone, developed high-resolution numerical smartphone models, and calculated SARs under various conditions.

Low frequency communication such as MHz band communication is a feasible method to reduce signal attenuation from the human body, although slow data rates limit its range of applications. In this paper, we designed two coil antennas for wireless capsule endoscopic (WCE) medical image transmission, including a small-sized dual-band transmitting antenna that can be placed inside the WCE and a corresponding receiving antenna that can be mounted on the abdomen of the human body. The proposed antennas can be fed by a battery-powered impulse radio transceiver that contains five signal peaks in the MHz band, and two signal peaks (38.5 and 57.6 MHz) are selected for antenna design to realize dual-band communication with higher data rates. Dimensions of the transmitting antenna and the receiving antenna are π × (5.5)2 × 2 mm3 and π × (40)2 × 4.8 mm3 , respectively. The antenna distance that satisfies the WCE medical image transmission requirements is roughly estimated by the received power from the transceiver. With the antenna distance of 50 mm, the attenuation is 33 and 47 dB at 38.5 and 57.6 MHz, respectively. With the antenna distance of 100 mm, the attenuation is 39 and 59 dB at 38.5 and 57.6 MHz, respectively. It can be estimated that proposed antennas can realize a total data rate of 2.5 Mbps within 100 mm antenna distance if two antennas are aligned or within 50 mm antenna distance if two antennas are misaligned to 60 mm.