|Budget Amount *help
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 2002: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
In order to reduce invasiveness of thermotherapy for malignant brain tumors, we have been investigating heating techniques using a re-entrant type applicator, which is a noninvasive heating apparatus.
In 2001, we conducted experiments to control the extent of heating. By making some improvements to the trial apparatus and changing the diameter of the re-entrant area, we were able to confirm that the extent of heating can be controlled to a maximum of about 80% of the heated tissue.
In 2002, while aiming for clinical use, a round window for inserting patients was placed on the lateral side of the re-entrant type applicator with a diameter of 120 cm and height of 120 cm that had been developed for research use. Initially, using three-dimensional computer simulation, we confirmed that electric field leakage to the outside area was below the allowance. We then measured electric field leakage using a phantom. We were able to confirm that the electric field was within the allowance at least 50
cm away from the window. This finding was presented at The 19th Annual Meeting of the Japanese Society of Hyperthermic Oncology.
Furthermore, a phantom in the shape of a human body was heated, and the distribution of temperature was measured by infrared thermography. When thermotherapy was conducted at 30 W for 15 minutes, the temperature at the core of the phantom increased by 4.5 degrees, while that at the surrounding area was less than 2 degrees, and no problematic hot spot was seen. This finding was presented at The Annual Meeting of Denshi-johotsushin at Shinetsushibu.
In an animal study, a beagle was inserted through the round window on the side of the re-entrant type applicator. Electric field leakage was also below the allowance at least 50 cm away from the window.
If re-entrant type thermotherapy is applied clinically, thermotherapy can be repeatedly performed in a noninvasive manner, thus increasing the efficacy of thermotherapy. Noninvasive thermotherapy in the head region using a re-entrant type applicator appears to be promising, and it should be clinically useful. Less