2014 Volume 64 Issue 2-4 Pages 170-175
We have measured set-up errors and calculated the planning target volume (PTV) for fixing human body on radiotherapy. The data of 61 patients was analyzed, who were treated with image-guided radiation therapy (IGRT) using On-Board Imaging (OBI) system in Hirosaki University Hospital. All averages of setup errors were less than 3 mm and it seemed not to be clinical problems. The maximum values of the PTV margin were 5.9 mm in the breast, and 5.5 mm in the prostate was 6.5 mm in the pelvic cavity. The results showed that set up margin should set within 7 mm for the planning target volume. We compared among three averages of set up errors on three kinds of upper limb fixture. The difference was 0.3 mm among three set-up errors. However, it was suggested to be almost equivalent because the value was very small clinically. This study suggests that we should use patient immobilization devices than thermoplastic shell, considering the cost and convenience when breast cancer. On this study, set-up margin were calculated precisely in Hirosaki University Hospital. These results seem to be helpful in planning of radiotherapy.
