A new applicator of RF capacitive heating for head and neck cancer

Research Project

Project/Area Number	07671021
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Radiation science
Research Institution	Kagoshima University
Principal Investigator	HIRAKI Yoshiyuki University Hospital, Kagoshima University Research Associate, 医学部・附属病院, 助手 (90264423)
Co-Investigator(Kenkyū-buntansha)	KAWANO Kazunori Faculty of Dentistry, Kagoshima University Research Associate, 歯学部, 助手 (50108750) TAKESHITA Tuyoshi Faculty of Medicine, Kagoshima University Research Associate, 医学部, 助手 (30274830)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Head and neck cancer / Deep heating / RF capacitive heating / U-shape applicator / Edge effect / 頭頸部腫瘍 / SAR分布 / 遮蔽板 / Overlay Bolus
Research Abstract	We devised a new type of applicator (U-shape applicator), with bending the flat electrode of 15 cm in diameter into U-shape. Japan hyperthermia society QA phantoms were heated with the U-shape applicator and with the flat applicator. The temperature in the phantom was measured with the Teflon coated thermocouples and the vertical sectional thermal distributions after heating were taken with a thermography unit. The untoward edge effect was reduced and favorable thermal distribution was obtained with the U-shape applicator. On the thermal profile after heating, the highest temperature zone was shifted to the shallower sides of the phantom with the flat applicator, and was near the core with the U-shape applicator. The change of the thermal distribution may be not only due to the decrease of the edge effects but the changes of the distance between both electrodes. In the clinical application to one of our co-workers who was suffering hypopharyngeal cancer, pain and other complication were reduced and the maximum temperature of the oral floor and at esophageal inlet was nearly 2ﾟC higher with the U-shape applicator than with the flat applicator. The change of the temperatures may be due to the decrease of the edge effects, the shortening of the distance between both electrodes, and improvement of non-uniform distance from electrodes to skin. U-shape applicator can be expected to play an important role in clinical hyperthermic oncology.