RadQA-DPO: A Radiology Question Answering System with Encoder-Decoder Models Enhanced by Direct Preference Optimization

Md Sultan Al Nahian, Ramakanth Kavuluru


Abstract
Extractive question answering over clinical text is a crucial need to help deal with the deluge of clinical text generated in hospitals. While encoder models (e.g., BERT) have been popular for this reading comprehension–style question answering task, recently encoder-decoder models (e.g., T5) are on the rise. There is also the emergence of preference optimization techniques to align decoder-only LLMs with human preferences. In this paper, we combine encoder-decoder models with the direct preference optimization (DPO) method for the RadQA radiology question answering task. Our approach achieves a 12–15 F1 point improvement over previous state-of-the-art models. To the best of our knowledge, this effort is the first to show that DPO method also works for reading comprehension via novel heuristics to generate preference data without human inputs.
Anthology ID:
2025.bionlp-1.10
Volume:
ACL 2025
Month:
August
Year:
2025
Address:
Viena, Austria
Editors:
Dina Demner-Fushman, Sophia Ananiadou, Makoto Miwa, Junichi Tsujii
Venues:
BioNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
101–113
Language:
URL:
https://preview.aclanthology.org/acl25-workshop-ingestion/2025.bionlp-1.10/
DOI:
Bibkey:
Cite (ACL):
Md Sultan Al Nahian and Ramakanth Kavuluru. 2025. RadQA-DPO: A Radiology Question Answering System with Encoder-Decoder Models Enhanced by Direct Preference Optimization. In ACL 2025, pages 101–113, Viena, Austria. Association for Computational Linguistics.
Cite (Informal):
RadQA-DPO: A Radiology Question Answering System with Encoder-Decoder Models Enhanced by Direct Preference Optimization (Nahian & Kavuluru, BioNLP 2025)
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https://preview.aclanthology.org/acl25-workshop-ingestion/2025.bionlp-1.10.pdf
Supplementarymaterial:
 2025.bionlp-1.10.SupplementaryMaterial.zip
Supplementarymaterial:
 2025.bionlp-1.10.SupplementaryMaterial.txt