This phantom is designed according to AAPM TG-111 findings. The phantom comprises three 20 cm thick PMMA cylinders 300 mm in diameter similar to the standard Pro-CT Dose phantom. The total length of the phantom is 600 mm. This allows capturing the majority of the scattered radiation and gives more accurate results than standard PMMA cylinders – 150 mm long, 320 mm in diameter. Due to the large mass of the phantom, it is manufactured in three separate sections. In order to keep these sections aligned, mounting screws are included in the design.