Aims and objectives:
Metal artifact reduction (MAR) reconstruction is used in presence of metallic artifacts in modern CT, where subsequent treatment dose calculation can be affected. Previous study  focused on the effect of MAR in CT numbers instead of relative electron density (RED) which is directly used in dose[...]
Methods and materials:
Two metal rods were attached to Gammex RMI467 phantom laterally. Various tissue equivalent rods with known RED were sequentially inserted into a hole where the artifacts were the most severe as shown in Figure 1. Phantom images were acquired using SOMATOM Definition Edge CT simulator with 120 kVp [...]
Figure 2 shows the CT numbers of the materials in metal-free, uncorrected and iMAR images. Differences between metal-free and uncorrected images increase with CT numbers. Larger differences between metal-free and uncorrected images are observed for bony materials. Figure 3 shows the CT numbers of [...]
The results indicate that metal artifact reduction improves the estimation of RED in presence of metallic artifacts in terms of not only the accuracy, but also smaller variations in homogeneous materials.
Chi-Wai Cheung MPhil MMedSc, Medical Physics and Research Department, Hong Kong Sanatorium & Hospital; Victor.CW.Cheung@hksh.com
 Ziemann, Christian, et al. "The effects of metal artifact reduction on the retrieval of attenuation values." Journal of applied clinical medical physics 18.1 (2017): 243-250.  Giantsoudi, Drosoula, et al. "Metal artifacts in computed tomography for radiation therapy planning: dosimetric eff[...]