X-Ray Imaging and Computed Tomography

Besides clinical computed tomography, several other medical CT modalities are in use, today. Interventional studies, for example, are often carried out under C-arm CT guidance, where a flat detector and a small x-ray source rotate around the patient. Oral and maxillofacial surgery, as well as the planning of dental implants, often relies on the so-called digital volume tomography (DVT), which is a dedicated flat detector CT system for the patient head. Radiation therapy even uses two CT modalities for image guidance: a clinical CT scan is used for planning, while the treatment unit itself is equipped with dedicated flat detector CT systems used for patient positioning and treatment verification. In the preclinical domain dedicated small animal CT systems are in use. They allow supporting longitudinal pharmaceutical studies that may aim at monitoring tumor response or the influence of other medication. Often, CT is used in multi-modality scenarios to add prior information to other modalities. Among those scenarios combinations of PET with CT or SPECT with CT are the most prominent ones in medical care.

The division “x-ray imaging and computed tomography” of the DKFZ aims at improving x-ray and CT imaging in all aspects, with a special focus on cancer detection and tumor characterization. While calibration, preprocessing and dose reduction applies to both, radiographic and tomographic imaging, sophisticated image reconstruction and artifact reduction techniques is our focus in CT research. This includes the development of new methods to perform real-time imaging simulta-neously with the radiation treatment, potentially combining the information obtained by the kV imager with the portal images obtained from the MV treatment beam, the development of new registration and reconstruction algorithms to compensate for patient motion, as well as the development of new multi-spectral imaging techniques to improve tumor diagnosis and to allow for quantitative tissue decomposition into the dominating chemical components. Further,
some of our projects aim at translating and adapting methods, originally developed for CT,
to other imaging modalities, such as MRI and PET.

[1] M. M. Lell, J. E. Wildberger, H. Alkadhi, J. Damilakis, and M. Kachelriess. Evolution in computed tomography. Investigative Radiology, vol. 50(9), pp. 629-644, September 2015. doi: 10.1097/RLI.0000000000000172.

[2] M.M. Lell and M. Kachelriess. Recent and upcoming technological developments in computed tomography: High speed, low dose, deep learning, multienergy. Investigative Radiology 55(1):8-19, January 2020. doi:10.1097/RLI.0000000000000601