Figure 9.

A representative image of the metal artefact insert and measurement of the artefact area. (a) A representative image of the metal artefact insert and region of interest; (b) the area where the pixel values are lower than the threshold. The white area is lower than the average polymethyl methacrylate (PMMA) pixel value—three times the PMMA standard deviation; (c) the area where the pixel values are higher than the threshold. The white area is higher than the average PMMA pixel value plus three times the PMMA standard deviation