Cardiac SPECT (Myocardial Perfusion)
Gated myocardial perfusion imaging with Tc-99m sestamibi or tetrofosmin under rest and pharmacologic or exercise stress. Historically the workhorse non-invasive ischemia test; now competing with coronary CTA, stress echo, stress MRI, and Rb-82 PET. Dedicated cardiac CZT cameras (GE Discovery NM 530c, Spectrum Dynamics D-SPECT) cut acquisition time and dose substantially versus general-purpose Anger cameras.
Clinical pathway
- Stress acquisition — exercise treadmill or pharmacologic (regadenoson, dobutamine), inject at peak stress, image 15–60 min later.
- Rest acquisition — separate injection, image after 60-min uptake.
- Gated acquisition — ECG-gated SPECT for wall motion, thickening, ejection fraction.
- Reporting — reversible vs fixed defects, transient ischemic dilation, EF, summed stress / rest / difference scores.
Typical systems
- GE Discovery NM/CT 670 (general purpose)
- GE Discovery NM 530c (dedicated cardiac CZT)
- Spectrum Dynamics D-SPECT (dedicated cardiac CZT)
- Siemens Symbia Intevo
- Siemens Symbia Evo
- GE Infinia Hawkeye (refurb workhorse)
- Philips BrightView XCT
Room + procedure characteristics
- Total visit: 2–4 hours (one-day rest-stress protocol) or split across two days.
- Dose: ~8–12 mSv (Tc-99m); higher with thallium; CZT cameras enable lower-dose protocols at matched image quality.
- Team: nuclear cardiologist + NM tech + stress RN.
Equipment considerations that bite
- CZT vs NaI is a clinical-program decision, not just a spec. CZT cardiac cameras run shorter acquisitions, accept lower injected dose, and support stress-first protocols. A general-purpose Anger camera handles cardiac workably but at older protocol lengths and dose.
- SPECT/CT vs SPECT-only — attenuation correction matters in obese / breast / diaphragm cases. A SPECT-only camera is fine for routine but less competitive with PET in mixed populations. See Quantum / SiPM notes for cross-modality context.
- Hot-lab / dose calibrator — the unsung infrastructure. Daily QC, weekly QC, NRC license posture all live here, not at the camera. A used camera deal that excludes hot-lab readiness is incomplete.
- Gated software — Q.Clear-equivalent quantitation, AICE-style noise reduction, automated polar maps. License tier shapes report consistency.
Operational reality
- Volume is declining in many markets as coronary CTA, Rb-82 PET, and stress MRI pick up share. SPECT remains dominant in community settings due to installed base and cost; refurb economics reflect this.
- Throughput is the stress lab + uptake-room count, not the camera. A camera idle waiting for stress completion is the most common operational pattern.
- Regulatory burden — NRC / Agreement-State license, RSO, dose records. The license is the gating constraint to operate, not the equipment.