Steffen studied Medical Engineering Sciences at the University of Lübeck, Germany. Within this program, he got the chance to be an intern at the University of California, Berkeley. He joined the Berkeley Imaging Systems Laboratory where he worked on comparing the sensitivity of MRI to Magnetic Particle Imaging. For his Master thesis, he completed a project on the accelerated reconstruction for small-animal pinhole PET at MILabs in Utrecht, Netherlands. In October 2017, Steffen started his PhD at the Image Sciences Institute of the UMC Utrecht and joined the Quantitative Medical Image Analysis Group. He is part of the program Deep learning in medical image analysis (DLMedIA) where he is currently working on the development of novel deep learning algorithms for the automatic analysis of high-dimensional medical images, mainly spectral CT. In September 2019, his project got transferred to the Amsterdam UMC where he continues to work on the analysis on high-dimensional medical images in the Cardiovascular Lab, under supervision of Prof. dr. Ivana Išgum.