Additional file 1: Figure A1. of Point-spread function reconstructed PET images of sub-centimeter lesions are not quantitative

The mold used to produce the twelve spheres [15]. The mold has an upper and lower part that can be split. A thin 0.4 mm diameterfishing line is placed through twelve spheres before assembling the two parts. The 18F-gel mixture is withdrawn into a syringe and injected into the lower part of the mold to avoid air bubbles. The vertical hole in the top and bottom of each sphere has a 0.6 mm inner diameter. Thus, the spheres can only be filled with an 18F mixture that is homogenous. The 18F mixture is held in place by capillary forces until it settles. Then, the two parts of the mold is split, and a string of 12 homogenous spheres are released. Figure A2. Top: A string with twelve 18F spheres (yellow) in air. Bottom: A string with twelve18F spheres (yellow) suspended in 11C silicone (blue). (DOCX 185 kb)