Evaluation on Usefulness of Applying Body-fix to Liver Cancer Patient in Tomotherapy

In every time radiation therapy set up errors occur because internal anatomical organs move due to breathing and change of patient's position. These errors may affect the change of dose distribution between target area and normal structure. This study investigates the usefulness of body-fix in clinical treatment. Among 55-60 aged male patients who has hepatocellular carcinoma in area of liver's couinaud classification, we chose 10 patients and divided two groups by using body-fix or not. When applying body-fix, we maintained a vacuum of 80 mbar pressure by using vacuum pump (Medical intelligence, Germany). Patients had free breathing with supine position. After working to fuse and consist MV-CT (megavoltage computed tomography) with KV-CT (kilovoltage computed tomography) obtained by 5 times treatments, we compared and analyzed set up errors occurred to (Right to Left, RL) of X axis, (Anterioposterio, AP) of Z axis, (Cranicoudal, CC) of Y axis. Average Set up errors through image fusion showed that group A moved 0.3±1.1 mm (Cranicoudal, CC), -1.1±0.7 mm (Right to Left, RL), -0.2±0.7 mm (Anterioposterio, AP) and group B moved 0.62±1.94 mm (Cranicoudal, CC), -3.62±1.5 mm (Right to Left, RL), -0.22±1.2 mm (Anterioposterio, AP). Deviations of X, Y and Z axis directions by applying body-fix indicated that maximum X axis was 5.5 mm, Y axis was 19.8 mm and Z axis was 3.2 mm. In relation to analysis of error directions, consistency doesn't exist for every patient but by using body-fix showed that the result of stable aspect in spite of changes of everyday's patient position and breathing. Using body-fix for liver cancer patient is considered effectively for tomotherapy. Because deviations between group A and B exist but they were stable and regular.