Siemens SOMATOM Definition Flash

Family: SOMATOM Definition

The dual-source CT that defined ultra-fast cardiac imaging for a decade. Two X-ray tubes + two detector arrays mounted at 95° on the same gantry — together they produce 2 × 128 simultaneous slices with effective temporal resolution of 75 milliseconds (half the gantry rotation of 0.28 sec). "Flash" mode scans an entire thorax in under a second at pitch 3.4.

Clinical positioning

Flash's defining use cases:

Cardiac CT without beta-blockade. At 75 ms temporal resolution, coronary motion is effectively frozen at any heart rate — patients don't need to be pre-medicated.
Pediatric scans at one-breath speed. The fast pitch lets a chest/abdomen/pelvis finish before a 3-year-old can move.
Dual-energy — two tubes at different kVp enable material decomposition (iodine maps, uric acid, calcium).

Specs

Dual source: 2 × 128 slices
0.28 sec gantry rotation (75 ms effective temporal)
Flash mode: pitch up to 3.4
Dual-energy: TwinBeam dual-energy modes
SAFIRE / ADMIRE iterative reconstruction
Straton tubes (Siemens-proprietary, liquid-metal bearings)

Tube architecture is different

Siemens Straton tubes in Flash are not interchangeable with GE Performix or Canon Aquilion tube lines — they're physically shorter and use liquid-metal bearings. Parts ecosystem is Siemens-specific.

Service reality

Late-model Flash (post-2013 revisions) command premium refurb prices; early Flash are entry-tier dual-source. Dual-tube architecture means two of every wear item — budget for that in service planning.