The capability to produce customizable 3D printed imaging phantoms out of a growing number of materials has contributed to the increased use of such phantoms in clinical practice and research. Many of these materials have not been characterized at clinically relevant parameters for nuclear medicine imaging. In this work, we measured the attenuation of several 3D printing metal-infused filament materials with the potential for blocking 122 keV gamma photons using a scintillation detector. Understanding the ability of each material to attenuate gamma rays would allow modelling of varying levels of attenuation required for different body tissues at this energy. In addition, it allows for the determination of the thickness of the material needed to attenuate 122 keV photons, in order to build high-contrast spatial resolution phantoms. To achieve this goal, we performed attenuation experiments for three different 3D printing materials in this work (Tungsten infused Acrylonitrile Butadiene Styrene (ABS), Iron infused Polylactic Acid (PLA), and Stainless Steel (SS) infused PLA), by observing gamma transmission through blocks made of each material as a function of thickness. A Cobalt-57 (Co-57; 122 keV) source was chosen because of its relevance to nuclear medicine. Tungsten infused ABS showed the highest measured attenuation coefficient out of the three candidates at this energy (1.452 cm²/g). We further designed and 3D printed an imaging phantom to aid in characterizing the spatial resolution of novel gamma imaging systems at the above energy. The phantom design contains multiple line pairs (lp) located in four quadrants ranging from 1.2 mm – 8 mm. The 3D printed phantom was imaged by a molecular breast tomosynthesis (MBT) gamma camera. Assessment of the intrinsic spatial resolution of the MBT camera showed that our 3D printed phantom might be a viable option for routine spatial resolution quality control (QC) of gamma cameras used in clinical practice.

从越来越多的材料中生产可定制的 3D 打印成像模型的能力有助于增加此类模型在临床实践和研究中的使用。许多这些材料尚未在核医学成像的临床相关参数下进行表征。在这项工作中，我们使用闪烁探测器测量了几种 3D 打印金属注入灯丝材料的衰减，这些材料具有阻挡 122 keV 伽马光子的潜力。了解每种材料衰减伽马射线的能力将允许对不同身体组织在此能量下所需的不同衰减水平进行建模。此外，它还允许确定衰减 122 keV 光子所需的材料厚度，以构建高对比度空间分辨率幻影。为了实现这一目标，我们在这项工作中对三种不同的 3D 打印材料（注入钨的丙烯腈丁二烯苯乙烯 (ABS)、注入铁的聚乳酸 (PLA) 和注入不锈钢 (SS) 的 PLA）进行了衰减实验，通过观察伽马传输通过由每种材料制成的块作为厚度的函数。选择 Cobalt-57（Co-57；122 keV）源是因为它与核医学相关。注入钨的 ABS 在该能量 (1.452 cm 通过观察由每种材料制成的块的伽马透射作为厚度的函数。选择 Cobalt-57（Co-57；122 keV）源是因为它与核医学相关。注入钨的 ABS 在该能量 (1.452 cm 通过观察由每种材料制成的块的伽马透射作为厚度的函数。选择 Cobalt-57（Co-57；122 keV）源是因为它与核医学相关。注入钨的 ABS 在该能量 (1.452 cm² /克）。我们进一步设计并 3D 打印了一个成像模型，以帮助表征上述能量下新型伽马成像系统的空间分辨率。体模设计包含多个线对 (lp)，位于 1.2 mm – 8 mm 的四个象限中。3D 打印的体模由分子乳房断层合成 (MBT) 伽马相机成像。MBT 相机固有空间分辨率的评估表明，我们的 3D 打印体模可能是临床实践中使用的伽玛相机的常规空间分辨率质量控制 (QC) 的可行选择。