Table 1.

Description of the design of inserts used to assess image quality parameters

Image quality parameter	Insert design
Mean pixel value	Pixel value insert comprising five discs, 25 mm in diameter and 3-mm thick, of aluminium, PTFE, Delrin®, LDPE and air, stacked vertically and encased in PMMA
Contrast-to-noise ratio	Five inserts of aluminium, PTFE, delrin, LDPE and air. Each comprise five rods of the relevant material, 17 mm in length, of increasing diameter from 1 to 5 mm, positioned at regular intervals at a distance of 8.5 mm from the centre, encased in PMMA
Noise and uniformity	Phantom section filled with PMMA inserts
Titanium artefacts	Three equally spaced titanium rods of 5.2-mm diameter and 17-mm length

LDPE, low-density polyethylene; PMMA, polymethylmethacrylate; PTFE, polytetrafluoroethylene.