Buying Guides / Buying guide / PET/CT
For practical purposes, the standalone PET scanner is a legacy device. The clinical world moved to PET/CT — a PET detector ring fused with a CT scanner in one gantry — for reasons that are worth understanding, because they explain why the refurbished market is almost entirely PET/CT and why that is the right place to spend.
MIS sources, installs, and services GE PET/CT from the Discovery ST/STE generation through the digital Discovery MI and Omni Legend. Here is what actually changed and how to think about it when buying used.
Two problems made standalone PET clinically limited. First, attenuation correction: PET needs a map of how tissue absorbs photons to produce quantitatively accurate images, and older PET used slow, noisy transmission sources (like germanium rods) to build it. The CT in a PET/CT generates that attenuation map in seconds with far better quality. Second, localization: a PET image shows metabolic activity but little anatomy, so a hot spot could be hard to place precisely. Fusing PET with CT puts the metabolic signal directly onto detailed anatomy, which is decisive for oncology staging, restaging, and treatment planning.
CT-based attenuation correction also slashed scan times, turning hour-long studies into far shorter exams and lifting throughput substantially. Just as important, it improved the reliability of the standardized uptake value (SUV) — the quantitative measure oncologists track across studies to judge response to therapy. Reproducible SUV is hard to deliver on standalone PET and is a core reason PET/CT became the standard of care.
When buying refurbished PET/CT, the meaningful axis is detector technology and generation. Older BGO-crystal systems (e.g., Discovery ST) are serviceable workhorses for routine oncology. LYSO-crystal and time-of-flight systems (e.g., Discovery STE and later) improve sensitivity and image quality. Digital silicon-photomultiplier systems (Discovery MI, Omni Legend) represent the current high end with the best sensitivity and shortest scan times. Match the generation to your volume and case mix — and pay close attention to the CT side and detector condition, not just the PET ring.
| Factor | Standalone PET | PET/CT |
|---|---|---|
| Attenuation correction | Slow transmission source | Fast, high-quality CT-based |
| Anatomic localization | Limited | Precise PET + CT fusion |
| Scan time / throughput | Long | Much shorter |
| SUV reproducibility | Harder | Reliable — oncology standard |
| Refurbished availability | Effectively legacy | Full range (BGO → LYSO/TOF → digital) |
There is essentially no case for buying a standalone PET today — buy PET/CT. The real decision is which generation. For routine, cost-sensitive oncology programs, a refurbished LYSO-class system is an excellent value. For high-volume centers or programs that need the best sensitivity and shortest scans, digital systems are worth the premium. Because PET/CT is two scanners in one room, siting, shielding, the CT tube, and detector condition all matter — and we quote the full install and service scope so nothing surprises you after delivery.
No. PET/CT replaced standalone PET because the integrated CT provides fast, high-quality attenuation correction and precise anatomic localization. The refurbished market is almost entirely PET/CT for this reason.
CT-based attenuation correction is faster and more accurate, the fused images localize metabolic activity onto detailed anatomy, scan times are much shorter, and SUV measurements are more reproducible — which oncology depends on.
Match generation to case mix: BGO systems for routine oncology, LYSO/time-of-flight for better sensitivity and value, and digital SiPM systems (Discovery MI, Omni Legend) for the highest performance and shortest scans.
Both halves of the system: PET detector condition and the CT side (tube, detectors), plus siting and shielding. MIS evaluates the full system and quotes install and service as one scope.
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