Evaluation of Radiation Treatment Planning By Computed Tomography Metal Artifact Reduction Algorithm

The objective of this study was to evaluate the usefulness of Computed Tomography (CT) images acquired through repeated subtraction reconstruction algorithms to reduce metal artifacts in CT Treatment Planning System (TPS).
Origin images of Gammex phantom and Rando phantom and non-orthopedic metal artifact reduction (O-MAR) images were obtained after high density implantation. O-MAR applied images were also obtained. For evaluation of images, regions of interest (ROI) were set at five tissue rods and three points directly affected by artifacts in Gammex phantom. CT number and noise were compared and analyzed. Based on the investigated results using the Gammex phantom, three virtual cylinder target volumes were set on the Rando phantom to dose change of the radiation treatment planning according to the O-MAR. The average dose was then compared and analyzed.
CT number difference according to the application of O-MAR showed significant difference among lung and bone rod and 3 ROI directly affected. Noise difference according to O-MAR application was significantly different in rod except for bone rod. In the treatment plan using Rando phantom, non-O-MAR and O-MAR images showed -4.3 ~ 1.9% and -0.4 ~ 2.3% dose differences, respectively.
Applying an O-MAR can reduce image distortion due to high-density implantation, improve image quality, and correct CT numbers.