Fig. 1.

Quasar Phantom (a), Cedary lung tumor insert (b), CT scan of cedar lung tumor insert (c). The insert is composed of cedar wood and contains an offset, 3 cm diameter, plastic sphere to be used as lung and tumor surrogates respectively. The CT number and density of cedar ranges 290–400 and 0.25–0.32 g/cm³, which compares favorably with lung (140–300 and 0.15–0.33 g/cm³ respectively). The CT number and density of the plastic sphere was 950 and 0.98 g/cm³.