Abstract
AIM: In this study, we clarified changes of the surface dose to a low-density material on a carbon couch and verified whether a novel rigid couch (HM couch) could reduce the surface dose. MATERIALS AND METHODS: We measured the surface dose using only a carbon couch (iBeam Couchtop STANDARD; BrainLab), a low-density material (Styrofoam board) on the carbon couch, and an HM couch for 6 and 10 MV photon beams. RESULTS: A 5-cm styrofoam board placed on the carbon couch reduced the surface dose by approximately 7-9%, while it had no impact on the depth dose profile; however, in use, such a thickness may cause collision of the patient with the gantry head. The HM couch reduced the surface dose by approximately 7-9% and shifted the depth dose profile by approximately 0.4 cm in the depth direction compared to the carbon couch. CONCLUSION: The HM couch has the potential to reduce skin toxicity and is expected to be useful in clinical practice instead of carbon couches.