About
I am a postdoctoral scholar in the Department of Radiation Oncology at Stanford University, supervised by Prof. Xianjin Dai. I received my PhD in Computer Science from Lehigh University in 2026, where I was advised by Prof. Lichao Sun and developed trustworthy multimodal AI methods that integrate medical images and clinical text, including generalist biomedical foundation models. My research aims to bring AI into real-world clinical workflows and improve patient care, with current projects focused on medical image analysis and multimodal learning tailored to clinical needs.
Selected Publications All publications →
Generalist biomedical models
One vision-language model across many imaging modalities and tasks.
- Nature Medicine2024
- arXiv2026
MedGPT-oss: Training a General-Purpose Vision-Language Model for Biomedicine
Kai Zhang, Zhengqing Yuan, Cheng Peng, …, Lichao Sun, Yonghui Wu
- J. Biomed. Inform.2025
Scaling Up Biomedical Vision-Language Models: Fine-Tuning, Instruction Tuning, and Multi-Modal Learning
Cheng Peng, Kai Zhang, Mengxian Lyu, Hongfang Liu, Lichao Sun, Yonghui Wu
Agents and post-training for radiology
Agents that read chest X-rays step by step the way radiologists do, and training that rewards clinically correct reports.
- MIDL2026
RadAgents: Multimodal Agentic Reasoning for Chest X-ray Interpretation with Radiologist-like Workflows
Kai Zhang, Corey D. Barrett, Jangwon Kim, Lichao Sun, Tara Taghavi, Krishnaram Kenthapadi
- IJCNLP-AACL2025
EditGRPO: Reinforcement Learning with Post-Rollout Edits for Clinically Accurate Chest X-ray Report GenerationOral
Kai Zhang, Christopher Malon, Lichao Sun, Martin Renqiang Min
- KDD2026
MedJudge: Medical Multimodal Reward Modeling
Yunhong He, Kai Zhang, Jiarong Qian, …, Jing Huang, Lichao Sun
Evaluating medical agents
Where general-purpose models hold up in real diagnosis, and where they break.
- npj Digit. Med.2026
The Complexity Paradox of Generalist AI Agents in Medicine: Exploring GPT-5 for Real-World Multimodal Medical Diagnosis
Shaohui Zhang, Jiarong Qian, Kai Zhang, …, Lichao Sun, Jing Huang
- IEEE TRPMS2026
Evaluating GPT-4V for Multi-modal Medical Applications: A Comparative Study Using Open-source Datasets
Zhiling Yan, Rong Zhou, Kai Zhang, …, Xiang Li, Lichao Sun
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