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. Author manuscript; available in PMC: 2020 Dec 1.
Published in final edited form as: Med Phys. 2019 Oct 31;46(12):5514–5527. doi: 10.1002/mp.13862

Figure 1:

Figure 1:

(A) The 3D printed hole phantom. The phantom is a cylinder of photopolymer resin with 24 cylindrical holes whose programmed diameters range from 0.8mm to 4.0mm. The correct printed diameter was measured to be slightly smaller than programmed. The HU of the resin was ~100 as the background of CT images, and the holes were filled with 10% iodixanol mixed with water giving a Hounsfield Unit value of approximately 1000 in the 3~4mm holes for 100kVp images. (B) A high-resolution cone-beam CT image of. the machine drilled hole phantom. This phantom has CNC drilled holes from 0.3mm to 3mm with a precision of ±0.01mm. (C) The measured accuracy of FWHM in high-resolution cone-beam CT images as tested by the machine drilled hole phantom. We compared the ground truth diameter in the phantom and the FWHM estimate of diameters. The curve lifts off the line of identity around 0.8mm, showing that FWHM estimate can accurately measure diameter larger than ~0.8mm using images from the benchtop system.