Characterization of Using Infused PLA for 3D Printed Radiation Shielding

3D printing has been integrated in various applications in biomedical and medical imaging. A prominent new field is that of radiation protection and shielding, where the introduction of infused filaments makes it possible to manufacture customized 3D printed shielding. In this study we examine the use of a Polylactic Acid (PLA) infused with tungsten to shield a Positron Emission Tomography / Computer Tomography (PET/CT) scanner. The goal is to reduce the effects of the radiation emitted from outside the field-of-view (FOV) on the PET image and to protect the PET electronics against the X-rays from the CT. The shielding properties were examined using the radioactive sources Ba-133, Na-22, and Cs-137, as well as two X-ray sources with energy ranging from 20 to 125 kV. For X-rays below 40 kV, less than 1 cm of the tungsten infused shielding was sufficient to block more than 95% of the X-ray beam intensity. However, only around 30% of the 511-keV rays from Na-22 was attenuated by 3.5 cm of the 3D printed material. Our results support the application of tungsten infused PLA materials to shield the PET electronics. However, further studies are required to determine if shielding the PET crystals with tungsten infused PLA can improve image quality by reducing the contribution of scattered rays from outside the FOV. Additionally, our results show new possibilities for the use of infused filament in the field of X-ray imaging. For example, where lead coverings or skirts are excessively bulky or rigid, it could be employed to optimize shielding for radiation-sensitive organs.