discovered_01_2015

RESEARCH// THE HZDR RESEARCH MAGAZINE WWW.HZDR.DE 22 23 Researchers and physicians have a whole arsenal of radiopharmaceuticals at their disposal, the main one being ‘PET sugar’. This radiolabeled glucose derivative is effective because many types of tumors consume a lot of energy, and thus glucose. Radiolabeled amino acids, on the other hand, accumulate in brain tumors. Other radiopharmaceuticals serve to characterize tumors and provide important information for therapy plans. They are used to diagnose bone metastases and Parkinson’s disease or to visualize brain processes (neurotransmission). Research is constantly expanding this ‘toolkit’. HZDR staff manufactures radiopharmaceuticals in a certified GMP (Good Manufacturing Practice) area. It is legally authorized to process two of the most important substances: ‘GlucoRos’ ([F-18]FDG) and ‘NaFRos’ ([F-18]Fluoride). Of the twelve radiopharmaceuticals for clinical practice, available at the HZDR, six are commonly used. Milestones from 20 years of PET imaging As early as 2004, HZDR researchers developed an advanced method to correct patient movement during the PET scan. As one of the first research groups ever, they established a system for head scans with infrared cameras tracking the patient’s movements. These motions are mathematically assigned to millions of measured data points, preventing a ‘blurring’ of the images in real time. Another milestone is ROVER, a powerful and globally used software package. Marketed by ‘ABX advanced biochemical compounds’ in Radeberg, Saxony, ROVER guarantees fast and simple image processing as well as a standardized analysis of the generated images. Physicists and IT experts at the Institute of Radiopharmaceutical Cancer Research are constantly updating ROVER to reflect new developments – years ago, for example, it was adapted to combine PET and computer tomography (CT). Currently, it is being made compatible with facilities that combine PET and MRI (magnetic resonance imaging). The experts also make sure the software meets the needs of clinical practice. Radio oncologists, for example, are able to import the imaging data into their systems for radiation planning, which makes for a seamless integration of cutting-edge diagnostic methods into cancer therapy. Germany’s first PET/MRI whole-body scanner that was approved for use on patients was launched at the Helmholtz Center in 2011. This combination of PET and MRI was Europe’s second and the world’s third facility. ‘We served more than 2,700 patients during its four-year operation in Rossendorf,’ Jörg Steinbach explains. At the same time, intensive research efforts were made to optimize the innovative technology for clinical practice. In April of 2015, the machine was relocated to the University Hospital Dresden, right near ‘OncoRay’, the National Center for Radiation Research in Oncology, which is a joint venture between the University Hospital Carl Gustav Carus, the TU Dresden Medical School and HZDR. In order to be able to continue its research, HZDR has its own reserved time slot at the PET/MRI machine. Each year, 450,000 new patients develop cancer in Germany. Each patient, even each tumor is unique. Experts agree that the cure rate, which is currently about 50%, can only be raised further with individualized approaches to therapy. Progress in imaging technology makes it possible to detect, localize and characterize tumors with ever greater precision. Institute director Steinbach says: ‘At our institute, one clear focus is the development of radioactive tracers, especially radiotracers that can show not only the location and spread, but also the behaviors and functioning of tumors.’ That also requires biochemical basic research to find the best docking spots (i.e. biological target) for tumor-specific radiopharmaceuticals. Radiotherapeutics for internal radiation One of medicine’s biggest challenges is to develop new and effective forms of cancer therapy. Once a patient’s cancer has metastasized, the treatment method must be systemic, which means that the therapeutic agents must be transported to the metastases through the blood stream, as is the case in chemotherapy. New drugs that fight cancer cells either with radioactivity or via the body’s own immune system could achieve significant progress in the therapy of certain tumors. HZDR researchers are pursuing multiple routes. They study specific radiolabeled substances as well as nanoparticles. The idea is to use a carrier molecule or particle to transport radionuclides to the tumor, where the released radiation energy will kill the cancer cells. This presupposes radionuclides that remain where they are needed until the dose of radiation is released into the tumor. At the same time, it requires transport molecules or particles that are able to dock with great precision, at as many dispersed tumor cells throughout the body as possible. These are mainly peptides or proteins, such as antibodies. Their defined radiolabeling and characterization falls under the expertise of the institute. ‘We are also working on innovative drugs that can destroy cancer cells by harnessing the body’s own immune system,’ explains Michael Bachmann, second director at the Institute of Radiopharmaceutical Cancer Research. ‘One of our focus areas is antibodies that are able to detect two targets at Research focuses on radioactive drugs and molecular imaging.

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