The development and characterization of a novel yet simple 3D printed tool to facilitate phantom imaging of photoacoustic contrast agents

- A 3D printed phantom was designed and fabricated to validate photoacoustic contrast agents.
- Methylene blue was used as a contrast agent to validate the performance metrics of the phantom under the PA imaging system.
- The signal inherent to different types of tubing was quantified.
- India Ink and lipids were added to the media to simulate tissue absorption.
- The signal at multiple distances from the laser focal point was measured.

We report a new approach to preparing phantoms using 3D printing. This device supports plastic tubing containing the contrast agent and is immersed in a solution with absorption or scattering properties that mimic tissue. Up to 12 tubing samples could be placed in the device with sample-to-sample spacing as low as 0.3 mm and at a constant distance from the transducer (±0.16 mm), which is critical in validating photoacoustic contrast agents. We also studied different types of tubing and found that tubing with a larger outside diameter has more inherent signal. Both 40% India Ink and lipids in the immersion media modulated the signal. Finally, we created a depth phantom and found that signal decayed following a linear relationship (R2 = 0.997) with respect to distance from the focal point. We include computer-assisted drafting code the community can use to print this phantom or customized versions of this phantom.

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