These 3D printable tools are intended to facilitate assembly of polyacrylamide hydrogel phantoms suitable for evaluating performance of photoacoustic imaging devices. These specific phantom designs are used to evaluate object detectability and boundary buildup artifacts.

These tools were fabricated using an LCD 3D printer (Mars 2 Pro, Elegoo) based on UV-cured photopolymer resins. The phantom housing was constructed with overall dimensions of 127 x 80 x 53.5 mm, with the phantom region limited to a volume of 120 (L) x 72 (W) x 50 (H) mm (part #: 022). Connectors (part #: 009) were inserted into the openings on each side of the phantom housing, and a small amount of uncured photopolymer resin was added to the connection points. The housing assembly was then fully cured using a UV-curing machine (Mercury Plus, Elegoo). Two-face injection molds (parts #: 015-016) were used to fabricate imaging targets from custom tissue-mimicking polyacrylamide hydrogel formulations. The ends of a stainless steel wire running through the core of molded imaging targets were inserted into the connectors on each side of the housing and held in place using the 3D-printed stoppers (part #: 010). The phantom incorporated a total of 16 stepped-cylinder targets with three 5 mm-long sections of 1, 2 and 3 mm diameters. Rows of four targets horizontally spaced 8 mm apart were positioned at depths of 10, 20, 30 and 40 mm from the phantom’s top surface. Each target is molded from different hydrogel materials with different optical absorption coefficients. Each row of targets was spaced 5 mm apart in the phantom’s long axis (L) to minimize artifacts such as reflections or optical shadowing, and all targets were at least 20 mm away from the mold walls. After suspension of imaging targets, background hydrogel material was poured into the housing and allowed to solidify for 20 minutes.

Technical drawings, slicer files (Lychee) and Elegoo 3D-printer files (CTB) are included in the supplemental documentation.