Radiotherapy is one of the standard methods used to treat malignant tumors. The aim is to damage the tumor cells' DNA in order to ultimately destroy them. Proton radiotherapy is considered particularly gentle on patients.

OncoRay – supported by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Medical Faculty of TU Dresden, and the Carl Gustav Carus University Hospital – is considered a pioneer in the development and clinical introduction of technological innovations in proton therapy. In 2019, OncoRay clinically implemented DirectSPR, the most accurate method to date for CT-based calculation of proton penetration depth in patients, into patient care. The problem is that due to uncertainty in the proton range, healthy tissue surrounding the tumor must also be irradiated to ensure complete tumor coverage. The DirectSPR method, which is based on dual-energy CT, has made it possible to reduce the required safety margins by around 35 percent. However, this procedure could only be used for immobile tumors, such as those in the head or pelvis.

New generation of PCCT scanners
This gap will now be closed with the new PCCT technology. Siemens Healthineers introduced this groundbreaking technology in 2021. Previously, it was used exclusively in radiology for diagnostic purposes. At the end of May of this year, Siemens Healthineers introduced the next generation of PCCT scanners, which are now approved for use in radiotherapy as well. The world's first installation of this new generation single-source, photon-counting CT scanner , the NAEOTOM Alpha.Prime, in a radiotherapy department has now been realized at OncoRay.

“Siemens Healthineers has been cooperating successfully with OncoRay for many years in the field of CT imaging for radiotherapy. We are proud to now provide our partner with photon-counting computed tomography for radiotherapy and proton therapy. With the introduction of the NAEOTOM Alpha class, we are delivering on our promise to make powerful photon-counting technology accessible to more physicians and patients," said Gabriel Haras, Head of Cancer Therapy Imaging at Siemens Healthineers.

For Prof. Christian Richter, Head of the Department of Medical Radiation Physics at OncoRay and Principal Investigator for CT imaging in radiotherapy at HZDR, photon-counting detectors are the future of CT technology. "PCCT technology combines several advantages for its application in radiotherapy. It provides better and more accurate CT datasets, allowing us to plan radiation treatments more precisely and with a reduced imaging dose. In ten years, I can't imagine anything other than all CTs used for quantitative imaging being based on this technology. As OncoRay prioritizes patient care and research equally, research and clinical treatments go hand in hand. This means that technological advantages are clinically implemented as quickly as possible, allowing patients to directly benefit from successful translational research.“

Advantages of PCCT technology
PCCT technology offers numerous advantages for radiotherapy that the researchers at OncoRay will now evaluate and quantify in detail. For example, it is possible to increase the spatial resolution of images compared to conventional CT technology, achieve the same image quality with a lower imaging dose, or possibly both simultaneously. The scientists also assume that proton therapy can be planned even more accurately. More precise quantitative information on tissue properties could lead to more accurate predictions of the proton range in patients, ultimately enabling a further reduction in the safety margin. Both, imaging and treatment, will therefore be gentler. Importantly, PCCT will also enable the use of the DirectSPR approach for moving targets, allowing more patients to benefit from highly precise proton therapy.

Prof. Mechthild Krause, Director of OncoRay and Spokesperson at the DKTK Partner site Dresden, emphasizes: “With the detailed evaluation of the new CT technology and its subsequent gradual introduction into clinical practice, we are further strengthening our position as a leading centre for translational research in radiation oncology.” Professor Esther Troost, Head of the HZDR Department of Image-Guided Radiooncology, Dean of the Faculty of Medicine and, alongside Professor Krause, Director of the Clinic and Polyclinic for Radiation Therapy and Radiooncology, expects that the new PCCT device will be introduced gradually into patient care following a testing period. “In addition to enabling radiotherapy with fewer side effects, the PCCT images may even allow us to predict how the tumor will respond to therapy. Then, we can adapt the radiation treatment accordingly.”

Around 2,500 tumor patients per year are irradiated at the Departement of Radiation Oncology.

The new PCCT device is expected to be ready for use by mid-July, after the systems installation and commissioning has been finalized. The Federal Ministry of Research, Technology and Space (BMFTR) is funding the purchase of the PCCT device at OncoRay with a total of two million euros.

Link to original press release