  In these days, 3D-printer is on the rise in various fields including
radiation therapy. This preliminary study aimed to estimate the dose
characteristics of the 3D-printer materials which could be used as the
compensator or immobilizer in radiation treatment. The cubes which have 5cm
length and different densities as 50%, 75% and 100% were printed by 3D-printer.
A planning CT scans for cubes were performed using a CT simulator (Brilliance
CT, Philips Medical System, Netherlands). Dose distributions behind the cube
were calculated when 6MV photon beam passed through cube. The dose response for
3D-printed cube, air and water were measured by using EBT3 film and 2D array
detector. When results of air case were normalized to 100, dose calculated by
TPS and measured dose of 50% and 75% cube were 96~99. Measured and calculated
doses of water and 100% cube were 82~84. HU values of 50%, 75% and 100% were
-910, -860 and -10, respectively. From these results, 3D-printer in
radiotherapy could be used for medical purpose accurately.
