Spatial uniformity and resolution in inkjet-printed ²⁴¹Am phantoms imaged by digital autoradiography

Quantitative imaging of alpha-emitting radionuclides is essential for accurate dosimetry in radiopharmaceutical therapy (RPT). This study evaluates the performance of inkjet-deposited ²⁴¹Am sources imaged with the ionizing-radiation Quantum Imaging Detector (iQID), focusing on spatial resolution, substrate effects, and activity recovery. Line and areal phantom patterns were printed onto stainless steel, nickel, and gold-coated nickel substrates. Imaging was performed at 10 μm² and 20 μm² pixel resolutions, with normalization and alignment enabling direct comparisons. The iQID system successfully resolved printed features at 10 μm², and gold-coated nickel consistently exhibited the most confined and uniform deposition. Bitmap-based areal sources showed greater variability due to fluctuations in droplet frequency and inconsistent mass delivery. While iQID input settings influenced count rate, resolution remained largely stable across configurations. This study demonstrates the utility of combining precision inkjet printing with digital autoradiography for fabricating and characterizing high-resolution alpha-emitting sources, laying the groundwork for improved phantom development and dosimetric validation in RPT applications.