Evaluation of side effects of radiofrequency capacitive hyperthermia with magnetite on the blood vessel walls of tumor metastatic lesion surrounding the abdominal large vessels: an agar phantom study.

Abstract

BACKGROUND:

Magnetite used in an 8-MHz radiofrequency (RF) capacitive heating device can increase the temperature of a specific site up to 45°C. When treating a metastatic lesion around large abdominal vessels via hyperthermia with magnetite, heating-induced adverse effects on these vessels need to be considered. Therefore, this study examined hyperthermia-induced damage to blood vessel walls in vitro.

METHODS:

A large agar phantom with a circulatory system consisting of a swine artery and vein connected to a peristaltic pump was prepared. The blood vessels were placed on the magnetite-containing agar piece. Heating was continued for 30 min at 45°C. After heating, a histological study for injury to the blood vessels was performed.

RESULTS:

The inner membrane temperature did not reach 45°C due to the cooling effect of the blood flow. In the heated vessels, vascular wall collagen degenerated and smooth muscle cells were narrowed; however, no serious changes were noted in the vascular endothelial cells or vascular wall elastic fibers. The heated vessel wall was not severely damaged; this was attributed to cooling by the blood flow.

CONCLUSIONS:

Our findings indicate that RF capacitive heating therapy with magnetite may be used for metastatic lesions without injuring the surrounding large abdominal vessels.

• Authors: Noriyasu Kawai, Daichi Kobayashi, Takahiro Yasui, Yukihiro Umemoto, Kentaro Mizuno, Atsushi Okada, Keiichi Tozawa, Takeshi Kobayashi, Kenjiro Kohri
• Journal: Vascular cell (Vasc Cell) Vol. 6 Pg. 15 ( 2014) ISSN: 2045-824X [Print] England
• PMID: 25114787 (Publication Type: Journal Article)