Understanding the components of our CT imaging chain

Empowering low-dose precision medicine for everyone, everywhere

Low kV imaging and high-power technology allows you to produce high quality images with enhanced low-contrast resolution – helping you reduce radiation and contrast media dose. The basis for low kV imaging is the mass attenuation coefficient, which depends on the chemical composition and density of a material. In the past, it was not possible to keep image quality constant at all kV levels, as the X-ray tubes were not powerful enough to produce sufficient tube current (mA) at low kV levels.

Today, however, all our CT scanners from the SOMATOM® and NAEOTOM® lines are equipped with X-ray tubes that are powerful enough to produce high mA at low kV, so you can: 

• Use low kV imaging for patients of all sizes, including those with high BMI
• Reduce the cost per examination without exluding kidney-impaired patients, so you can minimize the need for contrast media
• Automatically select the tube voltage for multiple clinical applications across a wide range of kV settings, thanks to technology like CARE kV and CARE keV
• Achieve contrast enhancement at any kV level through the use of monoenergetic keV levels on the NAEOTOM Alpha

These benefits are the reason that low kV imaging and high-power technology make up an essential part of our CT imaging chain. In combination with intelligent technology – like CARE kV – low-dose CT imaging has become easier for patients of all sizes, providing invaluable diagnostic information. 

Thin-slice technology gives our CT imaging chain an extra edge by providing thin rows over the entire detector without collimating the selection. Acquiring these sub-mm slices does not compromise the detector coverage, scan speed, or time – providing you with optimal CT scan image processing. This process can be found in both of our CT imaging families: in scanners which use traditional energy integrating detectors like SOMATOM and NAEOTOM Alpha®, the world’s first photon-counting CT.

The Stellar detector in our SOMATOM CT scanners combines photodiodes and ADCs in one ASIC, offering a number of benefits in traditional CT imaging: 

• The Stellar detector uses approximately 70% less power and dissipates less heat than conventional detectors.
• It enables TrueSignal technology for a substantial reduction in electronic noise.
• It provides up to 3x more range than a conventional detector (up to 102 dB) thanks to HiDynamics for differentiating grey and white matter as well as lesion detection.
• It has an increased channel density of 17% for a finer sampling of small details – which is especially important for those bony structures thanks to thin-slice technology.

Photon-counting CT images from the NAEOTOM Alpha are processed differently than conventional, energy-integrating detectors. 

By converting photons directly into electrical impulses — and bypassing the intermediate step of scintillation light — the septa used to avoid optical cross talk between neighboring pixels become redundant and are therefore removed. This optimizes the dose efficiency of the detector, especially in ultra-high resolution CT imaging.

As photon-counting detectors measure electrical impulses instead of the light impulses created through scintillation, these detectors are able to clearly distinguish between signals created by X-ray photons-, and electronic noise — and subsequently eliminate the latter.

Compared to a high-end conventional CT scanner, the QuantaMax detector produces roughly ten times as much raw data with the same detector area. The result is highly detailed clinical images — with a slice thickness of as low as 0.2 mm, containing spectral results for every exam, free of electronic noise, and with higher contrast-to-noise ratio. This enables unprecedented clinical insights.