George Yiasemis

Postdoctoral Researcher · NKI & UvA · Amsterdam

George Yiasemis, PhD, MSc

AI for Oncology · Deep Learning · Computer Vision

Reconstruction Foundation models Medical imaging Digital pathology Open source

AI for Oncology Lab · Netherlands Cancer Institute · University of Amsterdam

I am a postdoctoral researcher at the Netherlands Cancer Institute, supervised by Jonas Teuwen, working on deep learning and computer vision for AI in oncology. My main focus is medical image reconstruction; I also work on foundation models and collaborate on AI projects involving radiology, surgery, pathology, biology, and proteomics.

I lead the open-source DIRECT reconstruction toolkit and contribute to foundation model research through AIFOFOMO in the Foundation Models for Oncology Lab. I completed my PhD at the NKI and UvA on deep learning for MRI reconstruction, adaptive sampling, and motion estimation, supervised by Jonas Teuwen, Jan Jakob Sonke, and Clara I. Sánchez.

georgeyiasemis@hotmail.com Amsterdam, Netherlands
Profile

About Me

AI researcher in deep learning and computer vision for oncology — mainly reconstruction and foundation models, with collaborative work on AI for medical imaging and molecular data.

Research Focus

  • Medical image reconstruction & inverse problems
  • Foundation models for oncology
  • AI for radiology, surgery, pathology, biology, and proteomics (collaborative)
  • Adaptive MRI sampling, dynamic imaging, and motion estimation
  • Open AI software (DIRECT, FastSlide, AIFOFOMO)

Current Role

May 2025 — Present · NKI, Amsterdam

Postdoctoral researcher in the AI for Oncology Lab, supervised by Jonas Teuwen, working on reconstruction, foundation models (AIFOFOMO), and collaborative AI projects across imaging and molecular domains at NKI.

PhD Thesis

University of Amsterdam & NKI · 2021–2025

What We Do Sample, We Must Learn to Reconstruct: From Missing k-Space Data to Meaningful Images — Deep Learning in MRI Reconstruction and Beyond

Supervised by Jonas Teuwen, Jan Jakob Sonke, and Clara I. Sánchez. My thesis combined deep learning with inverse problems, image reconstruction, adaptive sampling, and motion estimation for accelerated MRI — with publications at CVPR, MICCAI, Medical Image Analysis, and Magnetic Resonance Imaging.

Read thesis on UvA DARE →

Cover art for PhD thesis: What We Do Sample, We Must Learn to Reconstruct
Updates

News & Highlights

Recent updates from conferences, milestones, and ongoing research. Browse the complete archive on the news page.

MIRAGE preprint first page: Multi-scale Lesion-Informed Representation with Auxiliary Guidance for MRI Contrast Enhancement
Preprint

New preprint: MIRAGE for MRI contrast enhancement

Our new preprint MIRAGE: Multi-scale Lesion-Informed Representation with Auxiliary Guidance for MRI Contrast Enhancement is now on arXiv (arXiv:2607.19137), with Andrea Borghesi, Xin Wang, and Jonas Teuwen.

MIRAGE is a residual 2D U-Net with lesion-aware supervision for inferring contrast enhancement from pre-contrast breast MRI, improving lesion localization on the multi-centre MAMA-SYNTH dataset.

Conference

MIDL 2026 in Taipei — two poster presentations

I am attending the 9th International Conference on Medical Imaging with Deep Learning (MIDL 2026) in Taipei, Taiwan, 8–10 July at the Chientan Youth Activity Center — the first MIDL edition held in Asia.

I am presenting two works as posters: End-to-End Co-Optimization of Adaptive k-Space Sampling and Reconstruction for Dynamic MRI and Conditional Learned Reconstruction for Medical Imaging (with Nikita Moriakov, Jan-Jakob Sonke, and Jonas Teuwen).

CVPR 2026 CT Foundation Model challenge leaderboard: fomofo team ranked first on Task 1 All-data Track
CVPR Challenge

fomo.fo team wins CVPR CT foundation models challenge

Team fomofo from the Foundation Models for Oncology Lab placed first on Task 1 (All-data Track) of the CVPR 2026 Challenge on Foundation Models for General CT Image Diagnosis, evaluating frozen pretrained 3D CT representations with linear probing across chest and abdomen.

Our submission using TAP-CT achieved the top balanced accuracy (0.654) and AUROC (0.714) on the public leaderboard — part of the foundation model work I contribute to through AIFOFOMO at NKI.

Open Source

DIRECT Toolkit

Lead developer · NKI-AI

Open Source · Lead Developer

DIRECT

Deep Image REConstruction Toolkit

Open-source PyTorch pipeline for deep learning-based medical image reconstruction — MRI reconstruction, denoising, and dealiasing. Ships RecurrentVarNet, vSHARP, RIM, LPD, and VarNet with pretrained models in the Model Zoo and configs for Calgary-Campinas, FastMRI, and CMRxRecon.

303 GitHub stars
JOSS 2022 paper
Apache-2.0 Open license

Winner · Multi-Coil MRI Challenge 2022 · Runner-up · CMRxRecon 2023 · 2nd & 3rd · CMRxRecon 2024

DIRECT reconstruction example: zero-filled input, compressed sensing, and RIM reconstruction
Research

Selected Papers

Peer-reviewed and preprint work on reconstruction, computer vision, and deep learning for medical imaging.

Cover art for PhD thesis: What We Do Sample, We Must Learn to Reconstruct
PhD Thesis

What We Do Sample, We Must Learn to Reconstruct

PhD thesis at the University of Amsterdam and Netherlands Cancer Institute on deep learning for accelerated MRI reconstruction — from missing k-space data and adaptive sampling to self-supervised learning, cross-domain generalization, and clinical validation. First doctoral graduate from the AI for Oncology Lab.

E2E-ADS-Recon pipeline for frame-specific adaptive k-space sampling and reconstruction
MIDL · Dynamic MRI

End-to-End Co-Optimization of Adaptive k-Space Sampling and Reconstruction for Dynamic MRI

E2E-ADS-Recon jointly learns frame-specific adaptive k-space sampling and dynamic MRI reconstruction end-to-end — replacing fixed subsampling patterns with learned, temporally aware sampling that improves reconstruction quality across acceleration factors.

AI-reconstructed accelerated prostate MRI compared with conventional scans at R=1, R=3, and R=6
European Radiology · Prostate MRI

Diagnostic Assessment of AI Reconstruction on Accelerated Prostate MRI

Retrospective, paired, multi-reader multi-case study at UMCG showing that AI-reconstructed prostate MRI at reduced acquisition times maintains PI-RADS-based prostate cancer detection comparable to conventional scans — a step toward faster prostate MRI without compromising diagnostic performance.

Career

Experience

2025 — Present

Postdoctoral Researcher in AI

Netherlands Cancer Institute · AI for Oncology Lab · Amsterdam

Supervised by Jonas Teuwen. Reconstruction and foundation models (AIFOFOMO), plus collaborative AI work with radiology, pathology, surgery, biology, and proteomics colleagues.

2021 — 2025

PhD Researcher in AI & Medical Imaging

Netherlands Cancer Institute & University of Amsterdam

Supervised by Jonas Teuwen, Jan Jakob Sonke, and Clara I. Sánchez. Deep learning for accelerated MRI acquisition, reconstruction, adaptive sampling, and real-time tumor tracking. Lead developer of DIRECT.

2020

Quantitative Research Intern

Tickmill Europe Ltd · Limassol, Cyprus

Deep learning and statistical models for financial time-series forecasting.

Background

Education

2021 — 2025

PhD in Artificial Intelligence & Medical Imaging

University of Amsterdam & Netherlands Cancer Institute

Supervisors: Jonas Teuwen, Jan Jakob Sonke, Clara I. Sánchez. Thesis: What We Do Sample, We Must Learn to ReconstructUvA DARE

2019 — 2020

MSc in Artificial Intelligence (Distinction, 82.6/100)

Imperial College London

Thesis: Mirror Descent and Interacting Mirror Descent: Almost Dimension-Free Convex Optimization for Non-Euclidean Spaces

2015 — 2019

BSc in Mathematics (Distinction, 9.46/10)

University of Cyprus · Top graduating student, Faculty of Pure and Applied Sciences

Thesis: Computational Approach of the Orr-Sommerfeld Equation with the Finite Elements Method (10/10)

2018

Erasmus+ Exchange Semester

University of Patras, Greece

Recognition

Honors & Awards

2026
1st Place — CVPR CT Foundation Models Challenge (Task 1)

Team fomofo, Foundation Models for Oncology Lab · All-data Track, linear probing

2024
2nd & 3rd Place — CMRxRecon Challenge (MICCAI)

Marrakesh, Morocco

2023
Runner-up — CMRxRecon Challenge (MICCAI)

Vancouver, Canada

2022
Winner — Multi-Coil MRI Reconstruction Challenge

Calgary, Canada

2020
Corporate Partnership Programme MSc Group Project Prize

Best AI Group Project, Imperial College London

2019
Cyprus Mathematical Society Award

Best academic performance, Department of Mathematics and Statistics

2019
Top Graduating Student

Faculty of Pure and Applied Sciences, University of Cyprus

Life

Beyond Research

Outside of work, I enjoy running, swimming, gym, skiing, pilates, cooking, reading fiction, and travelling. I thrive in collaborative settings and value multidisciplinary teamwork across research labs and hospitals.

Running Swimming Gym Skiing Cooking Travelling English Greek Dutch (beginner) Spanish (beginner)