The dominant scintillator in clinical PET, lutetium-yttrium oxyorthosilicate (LYSO), requires expensive and energy-intensive crystal growth. The high instrumentation cost of LYSO-based PET systems limits their global deployment across much of the world. This presentation discusses two scintillator approaches offering realistic paths toward high-performance PET at substantially reduced cost, without compromise on diagnostic capability. The first is a revival of bismuth germanate (BGO). Once considered outdated due to its slow decay time and modest light yield, BGO has regained relevance through SiPM-based detection of Cerenkov photons, which unlocks time-of-flight (TOF) capability long thought unattainable with this material. At roughly one quarter the material cost of LYSO, BGO-based TOF PET offers a compelling cost-to-performance ratio. The higher stopping power of BGO, combined with TOF capability, has the potential to deliver image quality comparable to current LYSO-based TOF PET systems. The second approach involves lutetium oxide (Lu₂O₃)-based ceramic scintillators, specifically Lu₂O₃:Yb and the newly developed (Lu,Y)₂O₃:La. Rather than conventional single-crystal growth, these materials are produced by ceramic processing, a more scalable process with better dopant uniformity and lower fabrication cost. Their high density (8.6–9.4 g/cm³ versus 7.1 g/cm³ for LYSO) means thinner detector elements suffice for equivalent 511 keV stopping power, directly reducing material consumption. The (Lu,Y)₂O₃:La ceramic achieves a coincidence timing resolution of ~238 ps between identical 5-mm thick ceramic pixels, indicating TOF potential, and a light yield of approximately 19,000–21,200 ph/MeV. Simulations indicate that a 3 × 3 × 16 mm³ (Lu,Y)₂O₃:La pixel provides equivalent overall detection efficiency to a 20 mm LYSO pixel, while also offering better 511 keV photopeak absorption efficiency at that thickness, confirming the material efficiency advantage. BGO and Lu₂O₃-based ceramics can address the cost problem from different angles. BGO benefits from considerably cheaper raw materials than LYSO single crystal, while Lu₂O₃-based ceramics take advantage of a manufacturing route that avoids the cost and complexity of Czochralski crystal growth. Both require further development: BGO TOF PET demands careful electronics and detector design to fully exploit Cerenkov timing, while ceramic scintillators are still at an early stage of development, requiring improvements in light yield and decay time to match LYSO at the system level. Both technologies are genuine candidates for the next generation of PET instrumentation, with a cost structure that can support much broader global deployment.

MEDAMI 2026 Valencia

Contact: Patricia Sanjuan, Daniela Alvarado