RT Journal Article SR Electronic T1 A Visual Demonstration of Crystal Scintillation JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 3002 OP 3002 VO 61 IS supplement 1 A1 Frye, Ross A1 Frye, Sarah A1 Warhoover, Ryan A1 Hooper, Eric YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/3002.abstract AB 3002Objectives: The purpose of this study is to give a practical demonstration and explanation of a NaI crystal scintillation in a nuclear medicine department. In pursuit of this goal, the authors of this study tested the properties of a decommissioned tube (PMT) and NaI crystal from a well counter. Methods: After obtaining a decommissioned photomultiplier tube (PMT) and NaI crystal from a well counter, the metal over was removed to expose the crystal. To ensure that the crystal remained undamaged, the tube was x-rayed prior to the metal removal to determine the thickness of the stainless-steel cover (Image 1). After determining the thickness, a rotary tool and hand file were used to remove the outer cover. Once the outer cover was removed, our institution’s windowless hot lab was used as a darkroom. Different isotopes including Xe133, F18, and Cs137 were inserted into the crystal to test the scintillation ability. A digital photography camera was used to photograph the results which were in the blue/violet visible spectrum (Image 2). Different energies from 81 keV to 662 keV were tested and 1 mCi to 15 mCi amounts were tested with these isotopes. Results: A health physicist was contacted to learn why the scintillation event was in the blue/violet spectrum. It was determined that PMTs are most effective at near Ultraviolet(UV) light since the PMT is converting photons to an electronic signal, which is why blue/violet light works best. The maximum wavelength for NaI is 410 nm which is within the blue violet range of 400 nm to 500 nm. Furthermore, the crystal is doped with an impurity which determines the location of the holes/traps where the luminescence occurs by providing the energy levels within the forbidden gap. The Thallium used as the doping agent causes the location of the traps to be in a place that makes the primary emission occur at around 410 nm. Different energies did not change the visual light output; however, increasing the mCi amount increased the visual light seen. Conclusions: After researching several textbooks and surveying multiple technologists, it was determined that visual demonstrations of this nature are very rare. Although the blue/violet scintillation event is a common event, technologists rarely get the opportunity to see this occur. It was fascinating for the authors to learn that the scintillation event is in the blue visible spectrum. Further research is needed to obtain quantifiable data through the use of a photometer. A photometer could be utilized to measure light output to determine how variables such as temperature affect the crystal.