Dr. Markus Bach
Medical physicist in radiation oncology, Cologne, Germany
Welcome to my personal homepage. Here you’ll find who I am professionally, the apps and tools I build in my spare time, my writing, my photography, and a few stories from everyday life.
Working with purpose
I have always been curious about how things work, especially where nature, technology, and data meet. Today, that curiosity translates into my work as a medical physicist and project manager in radiation oncology.
My professional focus is on making complex clinical processes more robust and effective: improving treatment planning, evaluating data patterns, and translating requirements into practical tools and workflows. I enjoy bridging disciplines, aligning stakeholders, and leading teams from problem definition to implementation.
- 25+ years in physics
- 20+ years in medical physics
- PhD in physics
- 4 granted patents
- German MPE qualification
Focus: treatment planning, brachytherapy, SGRT, QA automation, radiation safety, AI-based methods
Career in brief
- since 2019 Medical Physicist, Radiation Protection Officer & Project Manager Onkologisches Therapie Centrum (OTC), Cologne
- 2009–2018 Technical Lead Medical Physics, Medical Device Consultant & Product Owner in proton therapy Varian Medical Systems Particle Therapy, Troisdorf
- 2004–2008 Medical Physicist & Radiation Protection Officer Paracelsus Hospital, Osnabrück
- 1998–2003 PhD in Physics University of Osnabrück & Fraunhofer IFAM, Bremen
- 1992–1998 Diploma in Physics University of Osnabrück
Recent activities
-
Reinforcement learning with an old acquaintance
I’m revisiting an old passion: reinforcement learning, this time by training an agent to play Super Mario, combining PPO with self-imitation learning and Go-Explore. The project is a hands-on playground for RL fundamentals (reward design, exploration, and learning stability). Code snippets and notes are available on GitHub.
And while the agent is playing by itself, you can go for a hike with alpacas or look up at the northern lights …
-
Want to see an aurora?
After missing a few opportunities, I built a small aurora forecast that combines multiple data sources to highlight promising nights. It’s designed to support planning, so you spend less time guessing and hopefully more time outside looking up. Try the app.
The story behind it: my Medium essay In Search for Dancing Lights.
-
Tiny worlds in Hamburg
After nearly 20 years, I returned to Miniatur Wunderland in Hamburg, still astonishing in its level of detail. This is a fine place where craftsmanship and storytelling meet in miniature. I can recommend a late visit with fewer people around you. If you like a challenge, try to find eight or more alien groups, and send me your pictures.
-
Ever had an alpaca on the leash?
Hiking with an alpaca is a unique and delightful experience! We took a tour near Cologne in the Bergisches Land. Alpacas are gentle (if the chemistry is right), curious, and fluffy animals, making them great companions for a hike. Just don’t expect them to carry your bags.
-
One in a million
What does “one in a million” look like? I picture it as a single red dot hidden among 999,999 gray ones. Create your own grids and get some assistance, or even the solution. Try the app.
I’ve also written a Medium article on that topic: One In A Million — Once In A Lifetime: Developing a sense of probabilities with visualizations.
-
March 14th
Before May the 4th, winter has to end, so we celebrate Pi Day (March 14th) with pie, not cake. This one was baked by my older daughter and cut into perfectly even twelfths. 😋
Painting with light
At the end of the last millennium, I lived next to a photographer. He taught me some basics about light and the golden ratio, but he detested my non-professional approach of taking many pictures and deleting the bad ones (at that time I was able to borrow a digital camera from the university, while he took analog images). I am still not an artist in his view, but if you can stand that blemish, here you’ll find a few files I rescued from the (digital) dustbin …
Barcelona Slow Rafting Out of the Blue Plitvice Lakes Neon Catacombs Guru Washington La Jolla Salvation Mountain Rust and Light San Francisco Fuji or furnace?
It is not good for the man to be alone …
Genesis 2:18 has a great idea, so here we are, six of us. While the fight against cancer motivates me and photography expresses my creativity, I feel at home with my beloved wife and children.
And sometimes we can express creativity together, like when we published our first iBook, Hoppel, Müffel und die Aromamöhrchen, in 2015 (only available in German).
I also have a spiritual family at KfO, the Kirche für Oberberg.