systemSiemensCTfamily: naeotom-alpha

Siemens NAEOTOM Alpha

Family: Siemens Healthineers NAEOTOM Alpha class · Modality: CT

First FDA-cleared photon-counting CT (2021). Replaces conventional energy-integrating detectors with the QuantaMax direct-conversion cadmium-telluride (CdTe) detector: each incoming X-ray photon is registered individually, its energy measured, and its signal captured without the scintillator blur step that defines every prior clinical CT. Every scan is spectral by default; every scan is high-resolution by default.

QuantaMax detector — what changes

  • Direct conversion — CdTe crystal converts X-ray photons directly to electrical charge. No scintillator, no light-conversion loss.
  • Photon counting with energy binning — each photon is registered and sorted into energy bins. Spectral information is available on every acquisition.
  • Quantum HD resolution — 0.2 mm slice thickness and effective in-plane resolution down to ~0.11 mm using the UHR reconstruction mode.
  • Electronic noise rejection — a counting threshold discards events below diagnostic energy; low-signal image regions look markedly cleaner than on energy-integrating CT.
  • No detector septa — finer pixel pitch than conventional multislice CT at a comparable or improved dose profile.

Dual-source architecture (Alpha / Alpha.Peak)

  • 2 × QuantaMax detectors (6 cm axial each) paired with 2 × Vectron tubes.
  • 2 × 120 kW generator (240 kW combined).
  • 66 ms native temporal resolution in dual-source acquisition.
  • Up to 737 mm/s scan speed and pitch 3.2 in flash acquisition.
  • Tin filter options (Sn100, Sn140, Sn150 kV) for low-dose / iodine-contrast-reduction protocols.
  • kV range 70 / 90 / 120 / 140 (plus Sn); tube current to 1300 mA.

Class members

  • NAEOTOM Alpha / Alpha.Peak — dual-source flagship.
  • NAEOTOM Alpha.Pro — dual-source mid-tier within the class.
  • NAEOTOM Alpha.Prime — first single-source photon-counting CT; lower capital and siting vs the dual-source Alpha.

Clinical positioning

  • Cardiac — beta-blocker-free coronary CTA at any heart rate; stent lumen evaluation at small pixel pitch; calcium blooming reduced by spectral monoenergetic reconstructions.
  • Oncology — spectral material decomposition and virtual non-contrast on every exam reduce multi-phase protocol redundancy.
  • Pulmonary / small-airway — UHR mode resolves sub-millimeter airway and vascular detail.
  • Pediatric — dose reduction from counting threshold + spectral virtual monoenergetic imaging.
  • Theranostics prep — spectral quantification of iodine distribution supports response assessment workflows alongside PET/CT.

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