Editorial [Hot Topic:Part-II Imaging and Treatment of Oncological Diseases (Guest Editor: J.F.W. Nijsen) ]

In this second part of the theme issue “Imaging and Treatment of Oncological Diseases” several image guided radionuclide based treatment approaches are discussed in depth: the renowned iodine-131 therapy for thyroid cancer is reviewed and also two novel treatment options for liver cancer patients. Furthermore, a review on bone seeking radiopharmaceuticals and one on liposomes for multimodal imaging are included. In these articles a clear strong point of nuclear medicine is demonstrated: radiopharmaceuticals can often be used to image and to treat disease. The article on liposomes is devoted to both nuclear imaging and magnetic resonance imaging (MRI). Currently, a very popular issue in medical imaging is the development of MR imaging agents in the frame work of “molecular imaging”. However, the number of nonradioactive imaging agents available is still very low compared to the radioactive imaging agents that are on the market. One part of the explanation is the one century of radioisotope research. The rest of the explanation is that research in MRI and CT has been mostly aimed on the apparatus itself while research in the field of nuclear medicine is aimed on the development of radiopharmaceuticals. The gamma camera is just used as a tool to visualize the distribution of the radioactive compounds. Recently, some progression has been made in the development of agents for MR imaging; nowadays a few new imaging agents have been clinically introduced. The most widely used are the iron oxide compounds. Other examples are liposomes and micelles labeled with iron, gadolinium, dysprosium or holmium. Most of these imaging agents are lanthanides which have useful properties for MR and can be easily incorporated in or attached to all kinds of carriers. Some of the new lanthanide systems are described in the article on nanocarriers by Koning and Krijger and in the article on radioembolization treatment of liver cancer by Vente et al. Imaging of drugs could be applied to personalize medicine. This would entail that each patient receives an individually designed therapy regarding dose, timing, and treatment response assessment. The amount of imaging compounds needed for a detectable signal or signal change in MRI is enormous compared to the quantities used in nuclear medicine. In the article of Seevinck et al., in part I of this theme issue, the factors affecting the sensitivity and detection limits of MRI and CT were compared to nuclear imaging. While nuclear imaging will certainly remain superior in detecting minute tracer amounts of imaging agents, it is expected that especially MRI will further increase the ability to depict low amounts in the patient. Ultimately, combining imaging modalities and the emerging development of multimodal imaging agents will overcome the shortcomings of each individual imaging technique and will radically advance the time of diagnosis and improve the treatment success in oncological patients. I would like to thank all authors for their contribution to this special issue and especially all expert referees that have reviewed the articles of this theme issue.