GE Infinia Hawkeye (SPECT/CT)

Family: GE Infinia · Modality: Nuclear Medicine / SPECT

Hybrid SPECT/CT variant of the Infinia — the first-generation Infinia Hawkeye shipped with a 1-slice low-dose CT; the later Infinia Hawkeye 4 added a purpose-built 4-slice low-dose CT with ~2× the coverage and resolution of the predecessor. The Hawkeye CT is explicitly designed for attenuation correction and anatomical localization, not diagnostic-quality CT imaging — the tube operates at approximately one-third of diagnostic-CT dose, and slow-rotation acquisition modes favor dose reduction over temporal resolution. Substantial global install base; the reference hybrid SPECT/CT platform across community nuclear-medicine for nearly a decade.

Hawkeye CT architecture

4-slice low-dose CT (Hawkeye 4) — GE's purpose-built CT subsystem mounted to the same gantry as the SPECT detector heads. Predecessor Hawkeye 1 shipped with 1-slice CT.
5 mm slice width.
Rotation modes — half-rotation (~14 s) or full-rotation (~23 s). Slow rotation trades temporal resolution for dose reduction.
Dose level — approximately one-third of diagnostic CT for equivalent anatomy. CT is not diagnostic-quality — it is explicitly designed for SPECT attenuation-correction and anatomical-localization purposes.
Helical mode on Hawkeye 4 — faster body acquisitions (~5 min total), effective dose typically <2 mSv.
Integrated gantry footprint — Hawkeye adds CT capability without enlarging the room footprint beyond what a traditional gamma camera requires.

SPECT side (shared with Infinia)

Dual-head variable-angle detectors: 180° / 90° / 76°.
NaI(Tl) crystals — 3/8" (9.5 mm) or 1" (25.4 mm) options.
59 PMTs per detector with digital per-PMT ADCs.
Energy range 40–511 keV — full clinical isotope range.
Collimator portfolio — LEHR, LEGP, MEGP, HEGP, Pinhole.

What Hawkeye adds over base Infinia

Attenuation correction via CT — materially improves quantitative SPECT accuracy vs transmission-source (Gd-153) attenuation correction on the non-CT Infinia.
Anatomical localization — fused SPECT + CT in a single exam; resolves the "hot spot on SPECT but where is it?" problem without a separate diagnostic CT.
Workflow integration — single-session hybrid imaging in the nuclear-medicine department.
Dose — CT adds patient dose on top of the radiopharmaceutical dose; Hawkeye's slow-rotation low-dose CT design minimizes the CT contribution.

Specs (Hawkeye 4)

4-slice low-dose CT · 5 mm slice width
Half / full rotation (14 s / 23 s)
~1/3 of diagnostic-CT dose
<2 mSv helical body scan
Dual-head variable-angle SPECT (shared with Infinia)
NaI(Tl) crystal 3/8" or 1" (SPECT side)
180° / 90° / 76° detector geometry
LEHR / LEGP / MEGP / HEGP / Pinhole collimators

Clinical applications

Cardiac SPECT/CT — myocardial perfusion with CT attenuation correction.
Bone SPECT/CT — localizing metastases, stress fractures with anatomical fusion.
I-131 post-therapy imaging — thyroid cancer with CT localization.
Parathyroid localization — Tc-99m sestamibi with neck CT fusion.
Oncology SPECT — tumor localization with CT anatomical reference.
Therapy-planning imaging — Y-90 SIR-sphere planning, theranostic pre-therapy localization.

Market position (secondary / refurb)

Large global install base. Infinia Hawkeye is a common legacy SPECT/CT platform in the secondary market.
Service ecosystem — GE OEM service; multi-vendor service coverage on both the SPECT side (NaI detectors, PMTs) and the CT side (purpose-built Hawkeye CT, distinct from stand-alone GE CT service patterns).
Successor pathway — Discovery NM/CT 670 (diagnostic-quality CT integrated with dual-head SPECT) → Discovery NM/CT 870 DR → current Discovery NM generation.
State radiation registration + NRC license required (NRC licensing).

Relationship to siblings and successors

GE Infinia — non-CT base platform.
Discovery NM/CT 670 / 870 DR — diagnostic-CT SPECT/CT successor class.
Discovery NM 530c — CZT cardiac-specific sibling in the Discovery NM family.