Codoped lutetium-based oxyorthosilicate scintillators (e.g., lutetium oxyorthosilicase (LSO) and lutetium-ytrrium oxyorthosilicate (LYSO) scintillators) codoped with transition metal ions (e.g., Cu2+) are described. The codoping can alter one or more optical and/or scintillation property of the scintillator material. For example, the codoping can increase scintillation light yield and/or decrease scintillation decay time. Radiation detectors comprising the scintillators, methods of detecting high energy radiation using the radiation detectors, and methods of altering one or more scintillation and/or optical properties of a lutetium-based oxyorthosilicate scintillator are also described.