PMT
Photomultiplier Tube — vacuum-tube photodetector that converts scintillation light from gamma-camera or PET crystals into an electrical signal. Used on conventional gamma cameras, SPECT, and PMT-era PET / CT (Discovery 690, Biograph 64 / mCT, Gemini TF). Replaced by SiPM (silicon photomultiplier) on current digital PET / CT and PET / MR platforms — and with similar shifts underway on selected gamma-camera platforms.
Why it matters to buyers: Dead PMT channels = regional sensitivity loss. Quarterly NEMA / image-quality phantom testing catches it before clinical impact. PMT-era platforms remain the value-tier refurb category in PET / CT and the dominant installed base in nuclear medicine; SiPM-era platforms are current generation.
Why it matters to engineers: Channel gain drift is normal; recalibration fixes most cases. Full PMT replacement is required when drift exceeds correctable range. Fragile to mechanical shock and sensitive to magnetic fields — which is why PET / MR uses APD or SiPM, not PMT, for the PET ring.
Related
- SiPM
- LYSO
- BGO
- Time-of-Flight
- Discovery 690 PMT
- Nuclear Medicine / SPECT
- PET / CT
- PET / MR (uses APD / SiPM, not PMT)
- First Digital PET (2016)
- Discovery 690 Field Guide