40 years of "Setting new standards" VS. "Following trends"

Second best is not an option

Explore the history of CT


"Röntgen must be crazy"


"Röntgen must be crazy"

Discoveries in Radiant Light

During an experiment back in 1895, Conrad Röntgen notices the outlines of the bones of his hand against a sheet of paper. He immediately grasps the significance of this chance discovery, continues his research, and publishes his findings. This prompts a real “X-ray craze” both among amateurs and experts alike. By 1900, medical care without the use of X-ray technology is already inconceivable. With images that give a complete view of certain parts inside the body, it is now possible to detect changes in the skeleton, and inflammation, gallstones or even tuberculosis in the lungs – without cutting the person open.

Early 20th century

Three dimensions from two images

Stereoscopic X-ray Imaging

By the middle of the 19th century, stereoscopy had already captivated the imaginations of photographers and observers alike. At the start of the 20th century, stereoscopic X-ray was used to combine two images to create a type of 3D picture of inside the body. It was not yet possible to visualize sharp contours and shadows free from superimpositions, yet a trained eye could notice the process of an inflammation, for example.

1930’s onwards

Rotation is the key

X-ray Tomography

The value of tomography in principle is clear at an early stage. At the beginning of the 1930’s, the radiation source and the film are rotated for the first time around a body part. This enabled imaging of a particular layer – a visual slice of the body measuring just a few millimeters. These pictures are free of overlap but are blurred outside the focus area.


Just the beginning

Theory of Computed Tomography

Between 1957 and 1963, Allan M. Cormack researches into the laws of radiation. He develops a method to easure the behavior of radiation inside the human body. Although he considers his findings to be purely theoretical, they indicate that it may be possible to achieve detailed imaging even of soft tissue using the propriate technology.


Ready for practical use

First Tomograph

Finally, at the start of the 1970’s, it becomes technically feasible to implement the theory of computer-based tomography in practice. Godfrey Hounsfield is considered the father of computed tomography since he developed the first working CT scanner with his team. As early as October 1971, it is ready for use in clinical examinations.


Swift start

SIRETOM Prototype Arrives

The new method providing images free of superimpositions causes “CT fever” and many companies join in the development process. From 1972, Siemens is also working intensively to develop the very first CT scanner. The hard graft pays off: With the prototypes installed at University Hospital Frankfurt, it is already possible to scan 1,750 patients and identify bleedings and tumors, for example, inside the human brain on the layered images.


New insights into the brain

Manufacturing Begins

SIRETOM, the first production model, provides images of inside the human brain with a resolution of 128 by 128 pixels – remarkable at the time. Two adjoining detectors move around the patient’s head in 180 single steps taking under five minutes. For the very first time, physicians are able to detect and localize brain injuries without causing the patient pain and long hospital stays for diagnosis alone. The SIRETOM proves a game changer for operation planning as well.

Get a real head start with the SIRETOM: Siemens‘ first CT head scanner


Now we want to see it all

Development of Whole-Body CT

Computed tomography soon becomes the examination method of choice for brain tissue. The contrast-rich images immediately create the desire among clinicians for a related advance: CT images of the whole body free of superimpositions to examine the liver, intestines and joints, for example. After three years of development, Siemens launches SOMATOM – its whole-body CT scanner – in 1977.


From top to toe

First Whole-Body CT

With its special fan-beam geometry and large detector arc, SOMATOM can capture the kidneys, the abdominal artery, and details of muscles, for instance – with a considerably higher contrast compared to all other imaging methods of this time. SOMATOM acquires 4- or 8-millimeter slices in a single 360-degree movement. And this takes just 2.5 to 4 seconds per slice, depending on the scan mode.

360 degrees in one go with SOMATOM: Siemens’ first whole-body CT scanner


At the beat of a heart

Heart CT

With the Cardio CT option for SOMATOM 2 it is already possible to synchronize imaging with the rhythm of the heart, so that the acquisition takes place right in between two heartbeats. For the first time ever, CT images of a patient’s heart are achievable that are largely free of disruptions due to movement of the heart.


In medicine and beyond

Research Drive

CT is not only useful in medicine: Archeologists can now also discover valuable clues to the inner part of mummies and dinosaur skeletons. Did the Archaeopteryx fly 145 million years ago? This is one of many questions that can be answered without making a scratch on the rare fossils.


CT to go: Far away from the nearest hospital

Mobile CT

An innovation from Siemens weighing 25 tons and measuring 15 meters in length takes to the road: A trailer truck carrying a complete CT system, including radiation-protected, air-conditioned examination area, a reporting room, and technician area. This now means that whole-body scans are possible even in remote rural areas without the need for a hospital.


Computed tomography unplugged


The high-performance DURA X-ray tube rotates around the patient in a single continuous movement at a record-breaking speed. In just 12 seconds, it captures more than 100 individual images with an astonishing level of detail – thanks to MULTIFAN technology. In the fastest CT scanner of its era, the power supply becomes wireless for the first time thanks to slip-ring technology. Without the need to stop the tube during the examination, the next major CT revolution was here: Spiral CT.

No wires – no delays with the SOMATOM Plus: the precursor of spiral CT technology


An idea with momentum

Spiral CT

Experts initially ridiculed the idea of a spiral CT, but Siemens continues to develop the concept. This method involves a detector rotating continuously around the patient table as the table slides smoothly through the gantry. The SOMATOM Plus-S is the only spiral-volume scanner at this time, and is capable of displaying entire body regions, such as organs, precisely in one run. Developments and changes in the disease pattern are noticed more easily.


More intelligent and efficient scans – at a click of the mouse

“Project 47”

Siemens’ development team “Project 47” designs the SOMATOM AR, which needs half the space, costs a third of the amount, and requires far less energy than the previous model. The compact unit is made possible by a “quite ingenious tilting base design,” according to developer Andres Sommer. This new version also has a user interface that can now be operated using a mouse; this simplifies the settings for medical staff by eliminating the need for manually typed commands such as “TOMO/2/20/120/50”.


Less is more


Siemens reduces the amount of radiation by 30% with the newly developed ceramic compound, “Ultra Fast Ceramic” (UFC). UFC is significantly more efficient than xenon detectors, and the afterglow time is shorter. Unlike before, almost all of the radiation is now transformed into useful information. Moreover, the automatic dosage software, “combined applications to reduce exposure” (CARE), can reduce the dose by up to 56%.


Vascular imaging becomes routine

Multislice CT

With the multislice adaptive array detector, making the difficult choice between volume size and higher resolution of details becomes a thing of the past. Non-invasive vascular imaging using CT is no longer a problem – and it is even possible to clearly visualize the heart in high resolution! Multislice technology and a slice thickness between 0.5 and 5 millimeters make it possible to capture the vascular system non-invasively and routinely with CT.

On the path to heart CT thanks to the SOMATOM Volume Zoom with multislice technology


Shorter gantry, relaxed patients

CT Combined with PET/SPECT

A short gantry (only 56 centimeters long) means more relaxed patients – and therefore enables better capturing conditions and higher image quality. These benefits, together with the low maintenance required, continue to make the SOMATOM Emotion a top seller – and a popular basis for various hybrid systems such as the Biograph PET-CT and the TruePoint SPECT-CT. From 2004 on, these hybrids enable the display of metabolic processes using PET or SPECT alongside the precise visualization of anatomical structures using CT.


Standardized user interface with syngo

syngo & syngo Evolve

With the syngo user interface, Siemens standardizes the operating system for all of its products. The new intuitive design facilitates and fastens learning the software as well as the workflow between different clinical departments. This development earns Siemens the “iF Interaction Design Award” in 2000. Thanks to the syngo Evolve service, Siemens systems can now remain state-of-the-art through hardware updates.


Sensational insights into even the finest vessels

16-Slice Multislice

With SOMATOM Sensation, multislice imaging with 16 – and later 64 – slices give physicians an insight into even the finest coronary side branches with a previously unseen level of clarity. Multislice technology establishes CT as an early detection method for coronary diseases.


Keeping cool: The Straton X-ray tube

Straton X-ray Tube

Siemens began conducting research on the rotary envelope tube as early as 1993. The task is not a simple one: Both the anode and the entire vacuum tube must rotate. Better cooling results in smaller anodes and a higher rotational speed, which finally leads to dual source technology. Waiting times between multiple scans become a thing of the past.


Twice the scanning power

Dual Source Technology

Dual source makes it possible to capture a beating heart within a fraction of a second and with minimal dose. Heart CT becomes routine, and other clinical fields are also able to benefit from this gentle, high-quality imaging modality. Bucking the trend of increasing the number of rows in the detector, Siemens successfully makes an important leap towards a second X-ray source with SOMATOM Definition. Dual Source CT also facilitates the breakthrough of a new imaging technology: Dual Energy CT. It is now possible to differentiate between different materials in the body.

With the power of two sources, Dual Source CT technology sets new standards in image quality and scan speed


More speed, less radiation

Second Generation Dual Source

Until this point, the radiation dose required for a heart scan was between 8 and 30 millisievert (mSv). SOMATOM Definition Flash lowers the dose to under one mSv, a fraction of a person’s natural radiation exposure per year, (around 2.4 mSv). This is made possible through overlap-free data recording and numerous other improvements to the Dual Source concept. A quarter of a second is now all it takes for an artifact-free heart scan and 5 seconds are all that are needed to scan from head to toe.


You can always count on IRIS

Reducing the Dose with an Algorithm

“Iterative reconstruction in image space” (IRIS) is an optimized image rendering method by Siemens that is capable of decreasing the radiation dose by 60%, a figure that could not be beaten at the time. IRIS paves the way for other pioneering algorithms in the field of dose reduction, such as those used for SAFIRE and ADMIRE. From 2011 onwards, FAST CARE software helps medical staff to optimize patients’ dosage while streamlining workflows.


All in a single chip

Stellar Detector

The Stellar detector is the result of a 6-year joint venture with semiconductor producer ams. The new technology combines all the components for transferring the signal in a single chip, together with the photodiode. Due to shorter signal paths, the electronic noise is reduced up to 30%.


Upper body scan in one second


The two StellarInfinity detectors and Vectron™ tube are doing an impressive job: They can capture the entire upper body in less than a second. Again, this is a new world record! With a gantry weighing 1.6 tons that rotates around the patient four times a second – while ensuring that the tube and detectors are positioned with the highest degree of precision – the world’s most powerful scanner is pushing the frontiers of technical feasibility. With no compromise on image quality, a lung can be scanned at a dose of just 0.1 millisieverts, for example – about the same as the natural radiation exposure during a flight from Germany to Argentina.

No compromises with SOMATOM Force: the most powerful CT scanner on the market today.


Cinematic Rendering

The new syngo.via Frontier platform provides access to powerful research prototypes and paves the way for the evaluation of new techniques. It offers opportunities for research and development that can help bring exiting new technologies into clinical practice in the future. One example is cinematic rendering, ultra-realistic depiction of CT datasets just like those seen in an anatomy textbook.