Development of high-Z doped plastic scintillators for SPECT imaging and radiometabolic dosimetry

A crucial role in fighting cancer is played by diagnostic imaging, thus any improvement in detectors performances can potentially lead to an enhancement in diagnostic images quality with consequent improved accuracy of the diagnosis and monitoring of treatment progress. Up to now most of the clinical SPECT systems exploit NaI(Tl) crystals, inorganic scintillators that, despite high radiation yield, low cost and ease of manipulation and shaping, suffer from limited count-rate capability because of their long scintillation decay times. The reSPECT project aims to improve the state of the art developing an innovative family of diagnostic imaging detectors based on a new class of organic scintillators doped with high-Z impurities. In this way the detection system can take advantage of enhanced count-rate performance driven by fast scintillation signals and an increased probability of the photoelectric effect, while ensuring the system can effectively handle high rates thanks to CMOS sensors performing the readout. The scintillators are polymerized inside the holes of a 3D-printed tungsten frame, which also serves as a collimator. We obtained promising performance in terms of clarity and dopant homogeneity. The light yield and timing performances of these innovative samples turned out to be comparable to the commercial ones. Ultimately, we were able to detect the 122 keV photopeak photons emitted by Co-57. The results obtained with this novel scintillator make it a promising detection system for theragnostic applications. The first goal is represented by the TRONDHEIM project, which aims to develop a portable dosimeter for mCRPC (metastatic Castration-Resistant Prostate Cancer) patients treated with Lu-177-PSMA-617 radiopharmaceutical therapy. This device should enable the measurement of the radiopharmaceutical washout curve – critical for optimizing dosage based on patient-specific metabolism – without requiring multiple SPECT scans, thus reducing discomfort for patients with pain and mobility issues.