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

The rapid development of clinical diagnostic imaging technology, in combination with medical and pharmaceutical research, has led to important improvements in healthcare. Imaging of biologic processes at cellular and molecular levels termed “molecular imaging” is one of the most innovative examples. In contradistinction to “conventional” diagnostic imaging, it sets forth to probe abnormalities that are the basis of diseases, rather than imaging advanced stage disease. This will be of great importance for the detection of early stages of malignant tumours. The development of highly sensitive agents will result in early tumour detection, which is expected to cause a substantial shift in healthcare procedures. Much more emphasis will be placed on diagnosing and treating disease before late symptoms occur, which demands a new category of therapy strategies. Development of innovative drugs and carrier systems is desired. Visualization of drug targeting and efficacy with high-resolution molecular imaging offers the opportunity to test and improve treatment in detail. However, not all presently used “high-end” imaging technologies can obtain molecular information. The different imaging modalities each have their own characteristics, strengths and weaknesses, which makes it beneficial to combine them. Therefore imaging techniques like single photon emission computed tomography (SPECT), positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) are combined resulting in SPECT-CT, PET-CT and PET-MRI. This offers the opportunity to merge the image of the agent distribution with the anatomy of the patient. Further improvements of these combined imaging apparatus are currently under investigation. Most interestingly, there is an increasing interest in the development of imaging contrast agents for these new opportunities provided by the combined imaging modalities. Drug carriers such as liposomes, micro- and nanoparticles, peptides and antibodies are able to modify the distribution of an associated substance. They can therefore be used to improve the therapeutic index of drugs increasing their efficacy and/or reducing their toxicity. If these delivery systems are carefully designed with respect to the target and route of administration, they will increase the specific targeting of the tumour. In addition, if these systems could be equipped with components that can be visualized with dedicated imaging modalities as MRI, nuclear imaging (SPECT and PET), CT or ultrasound or preferably a combination of these techniques, non-invasive imaging of the kinetic of the drug and/or image guided drug delivery is achievable. In this special issue the current developments in “imaging and treatment of oncological diseases” are described. In particular novel and future imaging agents for nuclear, MR and CT imaging will be explicated. The recent awareness of the advantages in combining imaging modalities linked to the development of new probes, which can be visualized by more than one imaging modality, is discussed in this issue. Furthermore, promising carriers like liposomes, antibodies and peptides to which imaging agents and therapeutic compounds as well can be attached are reviewed in this issue. Also dedicated therapeutic agents and devices that have proven their value in the treatment of specific oncological diseases like bone metastases, thyroid and liver cancer, are discussed in depth. Visualization of these treatment agents is an essential aspect in adequately treating these patients. In addition this theme issue offers insight into the advantages and disadvantages of the above mentioned imaging modalities among which the differences in detection limits and resolution, and will support the concerns that have to be considered by emerging new imaging agents. I would like to thank all authors for their contribution to this special issue. In my opinion this theme issue will give an excellent overview of the “ins and outs” of imaging agents and their explicit position in the battle to conquer cancer.