_version_ 1866911639410835456
author Sellergren, Andrew
Gao, Chufan
Mahvar, Fereshteh
Kohlberger, Timo
Jamil, Fayaz
Traverse, Madeleine
Tono, Alberto
Sadjad, Bashir
Yang, Lin
Lau, Charles
Yatziv, Liron
Chen, Tiffany
Sterling, Bram
Philbrick, Kenneth
Tiwari, Richa
Liu, Yun
Jajoo, Madhuram
Sankarapu, Chandrashekar
Vispute, Swapnil
Purandare, Harshad
Mishra, Abhishek Bijay
Schmidgall, Sam
Tu, Tao
Palepu, Anil
Park, Chunjong
Strother, Tim
Thapa, Rahul
Cheng, Yong
Singh, Preeti
Black, Kat
Matias, Yossi
Chou, Katherine
Hassidim, Avinatan
Goel, Kavi
Barral, Joelle
Warkentin, Tris
Shetty, Shravya
Webster, Dale
Virmani, Sunny
Steiner, David F.
Kirmizibayrak, Can
Golden, Daniel
author_facet Sellergren, Andrew
Gao, Chufan
Mahvar, Fereshteh
Kohlberger, Timo
Jamil, Fayaz
Traverse, Madeleine
Tono, Alberto
Sadjad, Bashir
Yang, Lin
Lau, Charles
Yatziv, Liron
Chen, Tiffany
Sterling, Bram
Philbrick, Kenneth
Tiwari, Richa
Liu, Yun
Jajoo, Madhuram
Sankarapu, Chandrashekar
Vispute, Swapnil
Purandare, Harshad
Mishra, Abhishek Bijay
Schmidgall, Sam
Tu, Tao
Palepu, Anil
Park, Chunjong
Strother, Tim
Thapa, Rahul
Cheng, Yong
Singh, Preeti
Black, Kat
Matias, Yossi
Chou, Katherine
Hassidim, Avinatan
Goel, Kavi
Barral, Joelle
Warkentin, Tris
Shetty, Shravya
Webster, Dale
Virmani, Sunny
Steiner, David F.
Kirmizibayrak, Can
Golden, Daniel
contents We introduce MedGemma 1.5 4B, the latest model in the MedGemma collection. MedGemma 1.5 expands on MedGemma 1 by integrating additional capabilities: high-dimensional medical imaging (CT/MRI volumes and histopathology whole slide images), anatomical localization via bounding boxes, multi-timepoint chest X-ray analysis, and improved medical document understanding (lab reports, electronic health records). We detail the innovations required to enable these modalities within a single architecture, including new training data, long-context 3D volume slicing, and whole-slide pathology sampling. Compared to MedGemma 1 4B, MedGemma 1.5 4B demonstrates significant gains in these new areas, improving 3D MRI condition classification accuracy by 11% and 3D CT condition classification by 3% (absolute improvements). In whole slide pathology imaging, MedGemma 1.5 4B achieves a 47% macro F1 gain. Additionally, it improves anatomical localization with a 35% increase in Intersection over Union on chest X-rays and achieves a 4% macro accuracy for longitudinal (multi-timepoint) chest x-ray analysis. Beyond its improved multimodal performance over MedGemma 1, MedGemma 1.5 improves on text-based clinical knowledge and reasoning, improving by 5% on MedQA accuracy and 22% on EHRQA accuracy. It also achieves an average of 18% macro F1 on 4 different lab report information extraction datasets (EHR Datasets 2, 3, 4, and Mendeley Clinical Laboratory Test Reports). Taken together, MedGemma 1.5 serves as a robust, open resource for the community, designed as an improved foundation on which developers can create the next generation of medical AI systems. Resources and tutorials for building upon MedGemma 1.5 can be found at https://goo.gle/medgemma.
format Preprint
id arxiv_https___arxiv_org_abs_2604_05081
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MedGemma 1.5 Technical Report
Sellergren, Andrew
Gao, Chufan
Mahvar, Fereshteh
Kohlberger, Timo
Jamil, Fayaz
Traverse, Madeleine
Tono, Alberto
Sadjad, Bashir
Yang, Lin
Lau, Charles
Yatziv, Liron
Chen, Tiffany
Sterling, Bram
Philbrick, Kenneth
Tiwari, Richa
Liu, Yun
Jajoo, Madhuram
Sankarapu, Chandrashekar
Vispute, Swapnil
Purandare, Harshad
Mishra, Abhishek Bijay
Schmidgall, Sam
Tu, Tao
Palepu, Anil
Park, Chunjong
Strother, Tim
Thapa, Rahul
Cheng, Yong
Singh, Preeti
Black, Kat
Matias, Yossi
Chou, Katherine
Hassidim, Avinatan
Goel, Kavi
Barral, Joelle
Warkentin, Tris
Shetty, Shravya
Webster, Dale
Virmani, Sunny
Steiner, David F.
Kirmizibayrak, Can
Golden, Daniel
Artificial Intelligence
We introduce MedGemma 1.5 4B, the latest model in the MedGemma collection. MedGemma 1.5 expands on MedGemma 1 by integrating additional capabilities: high-dimensional medical imaging (CT/MRI volumes and histopathology whole slide images), anatomical localization via bounding boxes, multi-timepoint chest X-ray analysis, and improved medical document understanding (lab reports, electronic health records). We detail the innovations required to enable these modalities within a single architecture, including new training data, long-context 3D volume slicing, and whole-slide pathology sampling. Compared to MedGemma 1 4B, MedGemma 1.5 4B demonstrates significant gains in these new areas, improving 3D MRI condition classification accuracy by 11% and 3D CT condition classification by 3% (absolute improvements). In whole slide pathology imaging, MedGemma 1.5 4B achieves a 47% macro F1 gain. Additionally, it improves anatomical localization with a 35% increase in Intersection over Union on chest X-rays and achieves a 4% macro accuracy for longitudinal (multi-timepoint) chest x-ray analysis. Beyond its improved multimodal performance over MedGemma 1, MedGemma 1.5 improves on text-based clinical knowledge and reasoning, improving by 5% on MedQA accuracy and 22% on EHRQA accuracy. It also achieves an average of 18% macro F1 on 4 different lab report information extraction datasets (EHR Datasets 2, 3, 4, and Mendeley Clinical Laboratory Test Reports). Taken together, MedGemma 1.5 serves as a robust, open resource for the community, designed as an improved foundation on which developers can create the next generation of medical AI systems. Resources and tutorials for building upon MedGemma 1.5 can be found at https://goo.gle/medgemma.
title MedGemma 1.5 Technical Report
topic Artificial Intelligence
url https://arxiv.org/abs/2604.05081