Radiology with a New Photon-Counting CT: Precise, Minimally Invasive, and Gentle on Patients—An Expert Interview with Prof. Thomas Vogl

University Professor Dr. med. Thomas Vogl is one of Europe’s leading experts in the field of diagnostic and interventional radiology. As Director of the Department of Diagnostic and Interventional Radiology and Nuclear Medicine at Frankfurt University Hospital and a professor at Johann Wolfgang Goethe University, he possesses extensive expertise in diagnostic, minimally invasive, and patient-friendly procedures.

Of particular note is his pioneering work in the development and application of innovative technologies—such as the angiography robot he helped develop—which enable more precise diagnoses and significantly improve the treatment of cancer.

Prof. Dr. Vogl specializes in complex interventional procedures, including transarterial chemoembolization, thermal tumor ablation, uterine artery embolization, and vertebroplasty. His work has set international standards and contributes significantly to the advancement of diagnostic and therapeutic methods. He places great emphasis on maintaining close contact with patients, precise planning, and interdisciplinary collaboration to optimize individualized treatment plans.

In addition to his clinical work, Prof. Dr. Vogl is a renowned scientist and author of numerous scholarly publications and standard reference works. He continuously promotes the use of state-of-the-art technologies, including artificial intelligence-based methods to improve image quality while reducing radiation exposure. Thanks to his many years of experience, his innovative spirit, and his commitment to quality assurance, Prof. Dr. Vogl is considered one of the leading figures in radiology in the German-speaking world and internationally. The Department of Radiology and Nuclear Medicine was the first facility in Hesse to put the Naetom Alpha Peak photon-counting CT system into operation. This innovative, next-generation device enables faster and more accurate imaging while significantly reducing the radiation dose for patients. Developed by German engineers, photon-counting CT represents a major advance for diagnostics, research, and patient safety. By utilizing this technology, the department is expanding its diagnostic capabilities and contributing to improved patient care.

The editorial team of the Leading Medicine Guide spoke with Prof. Dr. Vogl about this new CT system and learned more about its many advantages.

Radiology is a medical specialty that uses minimally invasive imaging techniques for the diagnosis and treatment of diseases. With the help of imaging technologies, procedures are precisely planned and performed with minimal invasiveness, resulting in less stress for patients and faster recovery times. The use of a photon-counting CT system represents a significant advancement in this regard. It is a modern imaging technique that differs fundamentally from conventional CT systems. While conventional CT scanners measure X-rays as a total signal and convert them into electrical impulses, a photon-counting CT detects individual photons—that is, individual X-ray quanta—and precisely analyzes their energy. This technology uses special detectors that not only count the number of incoming photons but can also distinguish their respective energies. This results in much more detailed and high-contrast image information, as different tissue types can be better differentiated based on their specific absorption properties.

Photon-counting CT (computed tomography) represents a significant technological advancement over conventional CT systems and contributes significantly to reducing radiation exposure during interventional procedures. 

“The new CT scanner represents a significant advance over previous methods. The classic X-ray principle, as originally discovered by Wilhelm Conrad Röntgen, was based on X-rays striking a photographic plate. There, the photons were converted into light, which in turn exposed the plate. This is how the first X-ray images were created—a principle that has endured for more than 100 years, technically refined but essentially unchanged. With the new technology—known as photon counting—a true paradigm shift is now taking place. Instead of converting the photons into light as before, they are counted directly. In this process, the photons pass through the human body as usual, undergo changes along the way, and ultimately strike special crystals. These crystals make it possible to precisely detect individual photons—without any conversion to light or brightness levels. This results in three key advantages. First, the same—if not better—image quality can be achieved with significantly less radiation. This means less exposure for the patient—a particularly important consideration for children or patients requiring repeated examinations. Second, these new devices are faster. Imaging is performed more quickly, procedures become more efficient, and diagnostic accuracy improves at the same time. Third, the spatial resolution is even higher than with previous systems. The finest structures can be visualized more clearly, and differences in tissue can be detected more precisely—a significant gain for diagnostic quality. This combination of reduced radiation dose, higher speed, and better image resolution significantly improves patient care. The average radiation exposure can be reduced by up to 50 percent. Medical staff also benefit from a higher level of safety because overall radiation exposure decreases,” explains Prof. Dr. Vogl, who is enthusiastic about the new CT scanner, adding:

“Amid all these advantages, one drawback must not be overlooked: this new technology is significantly more expensive. This is primarily due to the crystals used, which are necessary for photon counting—they are costly. The underlying electronics are also complex and correspondingly expensive. In addition, the devices must rotate extremely quickly, which also entails high technical requirements—and thus incurs additional costs. The maintenance contracts are also priced above the usual level. So this is by no means a “free upgrade.” That is why it is particularly important to carefully weigh the pros and cons of this technology against one another in order to clearly assess in which cases it actually offers decisive added value—and in which it might not.”

Interventional procedures, in which the highest precision and excellent image quality are crucial, benefit particularly from the technical advantages of photon-counting CT. 

These include, above all, tumor-targeted therapies such as thermal ablation, in which tumors are selectively destroyed using radiofrequency, microwave, or laser interventions. In these cases, photon-counting CT enables precise localization and monitoring of the treatment area, which enhances the therapy’s effectiveness and spares surrounding healthy tissue. In transarterial chemoembolization (TACE)—a method for the targeted treatment of liver tumors via catheter insertion and drug administration—photon-counting CT also facilitates the visualization of vascular structures and tumor blood supply. The improved contrast resolution and tissue differentiation support the precise placement of catheters and optimal management of the procedure. Furthermore, minimally invasive biopsies and drainage procedures benefit from clearer and more detailed imaging, as even small target structures can be better identified and safely punctured. In complex vascular interventions such as stent placements or embolizations, the improved image quality helps minimize the risk of complications and make the procedure more efficient.

The improved image quality of photon-counting CT plays a key role in making minimally invasive procedures more precise and safer. Thanks to the significantly higher spatial resolution and improved contrast differentiation, even the smallest anatomical structures, vessels, or lesions can be visualized with greater accuracy. This enables more accurate localization of the target area, which is crucial for the precise placement of catheters, needles, or other instruments. In addition, different tissue types and materials can be better distinguished from one another, which simplifies the planning of complex procedures and minimizes potential risks.

“Patients benefit particularly in cardiac diagnostics. Here, the new CT technology is bringing about a minor revolution: With significantly lower radiation exposure, the heart, coronary arteries, and even the heart valves can now be examined much more quickly and precisely. That is one of the greatest advantages. Another area where the benefits are significant is vascular diagnostics. The higher resolution and faster imaging allow for much clearer visualization of the blood vessels. The speed of the device also helps to freeze motion—a clear advantage in image quality and, consequently, in diagnostic accuracy. This is particularly relevant for preoperative planning, where as many details as possible must be known in advance. Here, the new technology provides a significantly improved foundation,” explains Prof. Dr. Vogl, adding:

“The device is also used in the field of early detection—particularly in lung cancer screening. There, the lower radiation exposure plays a decisive role. For individuals at increased risk, such as long-term smokers, the examination is particularly beneficial. In these cases, there is a clear indication. In general, however: For those without symptoms, a careful assessment must be made as to whether a radiation-based examination is warranted. Clear criteria have been established for lung screening, such as the duration and intensity of smoking. Technologically, this is a true revolution—and at the same time a remarkable feat of German engineering. Currently, this technology is available exclusively from German manufacturers. To date, there are no comparable systems from China, the U.S., or France. This is a true unique selling point. The fact that this device is now available at the clinic makes it all the more remarkable. It is now also in use at several major oncology centers. It offers decisive advantages in tumor detection: better localization, more accurate sizing, and more precise characterization. It also improves the planning of access routes, surgeries, or minimally invasive procedures—all in all, an enormous step forward.”

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On July 1, 2025, the first clinical examinations using the innovative photon-counting CT system Naeotom Alpha Peak from Siemens Healthineers were successfully conducted at Frankfurt University Hospital. The first patient to undergo the procedure was none other than soccer World Cup champion Mario Götze, who was examined as part of a sports medicine evaluation. The use of this latest generation of computed tomography marks a significant step forward in diagnostic imaging—with significantly improved image quality while simultaneously reducing radiation dose. The examination underscores the hospital’s commitment to applying medical innovation in clinical practice at an early stage.

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Prof. Dr. Vogl explains: “If all goes well, we expect to examine 40 to 50 patients per day using this machine in the future. That’s a considerable workload. The examinations themselves usually take only a few minutes. Our processes are organized so that patients can be examined at approximately 15-minute intervals. This technology is a German development—a true feat of engineering, ‘made in Germany.’ That’s something to be proud of. Global demand is enormous. Manufacturers can barely keep up with production—which shows just how strong the interest in this new generation of CT scanners is.”

Professor Dr. Vogl—thank you very much for the insight into the new CT technology!