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arXiv · 2610.21451

PET Quantification-Preserving Registration for Longitudinal Whole-Body PSMA PET/CT

Fryderyk Kögl·Anna Reithmeir·Daniel M. Lang·Emily Chan·Rickmer Braren·Julia A. Schnabel
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Abstract

We adapt the diffeomorphic coarse-to-fine LapIRN architecture for longitudinal whole-body PSMA PET/CT registration in the Learn2Reg 2026 PSMAReg challenge. The method combines affine pre-registration, multi-modal deformable registration, and test-time instance optimization. We further introduce PET biomarker preservation losses for metabolic tumor volume (MTV) and total lesion glycolysis (TLG), including Jacobian-based constraints, and a per-structure rigidity regularization for skeletal structures. The submitted configuration achieved 81.0% DSC and 6.17 mm HD95, with MTV and TLG errors of 3.3% and 3.3%, respectively, on our evaluation protocol. Code is available at https://github.com/koegl/psmareg.

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Fryderyk Kögl, Anna Reithmeir, Daniel M. Lang, Emily Chan, Rickmer Braren, Julia A. Schnabel. 2026-10-15. PET Quantification-Preserving Registration for Longitudinal Whole-Body PSMA PET/CT. https://arxiv.org/abs/2610.21451

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