DKFZ – Visualization in cancer research

Cancer is a horrible disease that affects many people. One of the research institutes that try to tackle it is the German Cancer Research Center (DKFZ), founded in 1964. This enormous institute has many departments, ranging from tumour biology to cancer imaging and radio oncology, which contribute to a better diagnosis and therapy of cancer.

In contrast to what most students were expecting regarding cancer research, we were welcomed by Dr. Bram Stieltjes and provided with a programme on the techniques and application of imaging. Dr. Frederik Laun presented many different visualising techniques that are used for medical purposes, such as X-ray radiation, CT (Computer Tomography), MRI (Magnetic Resonance Imaging) and PET (Positron Emission Tomography). They all have different resolutions and different uses. X-ray radiation, for example, is very robust and is suitable to detect bones. However, X-ray cannot be used to distinguish between different tissues. In contrast to X-ray, MRI can be used to distinguish between different human tissues in the whole body and analyse them.

The principle of MRI is derived from physics and chemistry. A very strong constant magnetic field is generated, along with a variable, and less potent magnetic field. Hydrogen nuclei will align their spins along the magnetic field, just like a compass aligns along the earth magnetic field. By disrupting the magnetic field with a pulse of radio-frequency (RF) radiation, the spins are rotated. By analyzing the part of the RF-radiation that gets absorbed, it is possible to retrieve structural information. In this way, a 3D image of the human body can be constructed. In addition, there is a specialized technique called fMRI (functional MRI), which detects the blood flow in the brains and thus measures the neuronal activity in the brains. Aside from these techniques, more experimental techniques are being investigated: for example using ²³Na nuclei, instead of hydrogen nuclei.

During a tour through the labs, we observed how enormous the MRI machines were and that a lot of safety measurements need to be taken into account. For example, due to the big electromagnetic field, the MRI apparatus is placed in a special building in order to minimize the interference with other technical equipments in the institute. Although the use of MRI is usually associated with serious applications, we were allowed to use it for two funny examples. Firstly, an MRI scan was made of a melon. From this scan it was easy to distinguish the watery juice inside the melon and the position of its seeds, without cutting it open. Furthermore, a couple of students experienced the phenomenon of induction after bringing an aluminium plate close to the MRI scan. Due to induction the aluminium plate counteracts the force enacted on it, when placed in the magnetic field of the MRI scanner. Because of this, the plate acted very strangely. For example, it fell over in slow motion.

In addition, Peter Nehler told that new computer applications for imaging are being developed. For instance, one of the research groups is developing a program to visualize bronchial trees in the lungs that contain lesions. This can be very useful for surgery planning. Even more remarkable is the development of an iPad application to visualise the organs of different patients. This last example is not meant for surgeons themselves, but for educational purposes and for patients.

Another application of using imaging and characterising network of neurons could lead to the prediction of specific diseases. As an example, it was pointed out that alterations in the connections of corpus callosum (part of the brain) could be detected at an early stage of Alzheimer’s disease, even when patients do not show any signs of the disease. This has a great potential to be used as a biomarker for Alzheimer’s. Despite its potential, it will not be used in the near future, because to prove the effectiveness of this biomarker, a large research project needs to be set up that requires many years; patients have to be monitored until they develop Alzheimer’s disease.

Although MRI scans are usually associated with research and treatment of human beings, we observed that DKFZ also use smaller MRI machines for research in animal models. On the one hand, we need animal experiments because it is not ethical to just start a clinical research (for example in pharmaceutical research). On the other hand, it is very hard to translate the results of animal experiments to human research. In order to translate the results better in cancer research, rats are often injected with human tumour cells and thus ‘humanized’. Interestingly, the rats were not provided with any ‘cage enrichment’, i.e. additional tools such as toys to make their life less stressful. The researcher explained that cage enrichment was not provided because it can differentiate the activity amongst rats and thus can interfere with the results. Apparently, the importance of the reproducibility of the results outweighs the inconvenience for the rats, which is always a very important issue in animal ethics.

In conclusion, the DKFZ provides a great opportunity to cooperate closely together and to combine new findings. Fast and correct diagnosis and prediction of neurological diseases and cancer could be a tremendous step forward to better treatments. However, in order to diagnose properly, researchers should understand the biological explanations for all these diseases. Moreover, they should understand the physical and chemical approach, to use techniques to detect them. Smart computer science techniques are needed to handle and store all the data, whereas pharmaceutical knowledge is needed to design proper drugs, which selectively target the desired system(s). In order to achieve this, interdisciplinary cooperation in cancer research is of the utmost importance. Lastly, there should also be more awareness of the gap between the research field and medical practitioners. Medical practitioners are hard to convince by researchers to use other techniques or drugs than they are used to.

Cedric Lau