Vacuuming and Pouring of the Phantom Material Samples into the Mold

To begin, place the hot beaker filled with the uniformly mixed, smooth, and homogenous phantom material solution into the vacuum chamber. Vacuum the samples on the lowest vacuum setting for two to three minutes. Remove any air bubbles accumulated on the surface using a metal spatula.

If air bubbles persist, reheat the mixture and repeat the vacuuming step until complete removal of the air bubbles. In the case of complex shaped molds, coat the mold with a thin layer of oil before pouring. Wear heat resistant gloves, use adequate protective equipment, and carefully pour the solution into a suitable mold without introducing any air bubbles.

Once poured, quickly remove any air bubbles from the top of the samples using a metal spatula. Allow the solution to be set overnight at room temperature. Three representative phantom material designs were created for photoacoustic imaging targeted for different system designs with different optical illumination and acoustic detection geometries.

The successful procedure resulted in smooth and homogenous phantom material preparation without trapped air bubbles, impurities, or artifacts. Insufficient removal of air bubbles and inhomogenous mixing of base components resulted in inhomogeneities in the resulting photoacoustic image.