What material reflects blue light from the event into the PMT in PET imaging?

The material that reflects blue light from the event into the photomultiplier tube (PMT) in PET imaging is aluminum oxide. This material is often utilized in scintillation detectors due to its effective light-reflecting properties, specifically in the blue wavelength range that is commonly produced during scintillation events.

When positrons emit gamma photons and interact with the scintillation material, they produce visible light as a result of the energy transfer. Aluminum oxide has a high reflectivity for this light, directing it effectively towards the PMT, which is essential for the detection and imaging processes in PET. Its properties help enhance the sensitivity and overall efficiency of the PET system in capturing the precise data regarding radiotracer distribution within the body.

The other materials listed, while having their own uses in various imaging applications, do not possess the same reflective qualities for the specific blue light wavelengths necessary for optimal PET imaging performance.