Radiological mapping and uncertainty quantification by a fast Microcanonical Langevin Monte Carlo sampler

Fuente: arXiv
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Auteurs principaux: Pan, Lei, Lee, Jaewon, Quiter, Brian J., Robnik, Jakob, Seljak, Uroš, Vavrek, Jayson R.
Format: Preprint
Publié: 2026
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author Pan, Lei
Lee, Jaewon
Quiter, Brian J.
Robnik, Jakob
Seljak, Uroš
Vavrek, Jayson R.
author_facet Pan, Lei
Lee, Jaewon
Quiter, Brian J.
Robnik, Jakob
Seljak, Uroš
Vavrek, Jayson R.
contents Radiological mapping plays a critical role in nuclear emergency response and environmental management activities. A radiation image, representing the spatial and intensity distribution of the radioactivity, is reconstructed from the radiation data and the associated contextual information. Typical image reconstruction methods, such as Maximum Likelihood Expectation-Maximization (ML-EM), only provide point estimates of the pixel or voxel activities without associated uncertainties. Here, we apply a new Microcanonical Langevin Monte Carlo (MCLMC) sampler for radiation image reconstruction and uncertainty quantification. The MCLMC sampler properties are first tested with synthetic radiation images. Methods to obtain the radiation distribution estimate and the associated uncertainty from the samples drawn by MCLMC are discussed. Given sufficient measurement statistics, the radiation distribution estimate obtained from MCLMC results closely resembles the ground truth with less risk of over- or under-fitting compared to ML-EM. When MCLMC is run in parallel on a GPU, the samples can converge to the posterior distribution in about 10 seconds for an image with $10^3$--$10^4$ pixels, which is significantly faster than other comparable Markov Chain Monte Carlo (MCMC) samplers. We also tested MCLMC on a dataset from a real distributed source radiological mapping campaign, and the reconstructed results agree well with ground truth. The fast MCLMC sampler therefore enables improved imaging accuracy and prompt uncertainty quantification for reconstructed radiation images, which can better inform decision-making in response to radiological events.
format Preprint
id arxiv_https___arxiv_org_abs_2602_16991
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Radiological mapping and uncertainty quantification by a fast Microcanonical Langevin Monte Carlo sampler
Pan, Lei
Lee, Jaewon
Quiter, Brian J.
Robnik, Jakob
Seljak, Uroš
Vavrek, Jayson R.
Medical Physics
Instrumentation and Detectors
Radiological mapping plays a critical role in nuclear emergency response and environmental management activities. A radiation image, representing the spatial and intensity distribution of the radioactivity, is reconstructed from the radiation data and the associated contextual information. Typical image reconstruction methods, such as Maximum Likelihood Expectation-Maximization (ML-EM), only provide point estimates of the pixel or voxel activities without associated uncertainties. Here, we apply a new Microcanonical Langevin Monte Carlo (MCLMC) sampler for radiation image reconstruction and uncertainty quantification. The MCLMC sampler properties are first tested with synthetic radiation images. Methods to obtain the radiation distribution estimate and the associated uncertainty from the samples drawn by MCLMC are discussed. Given sufficient measurement statistics, the radiation distribution estimate obtained from MCLMC results closely resembles the ground truth with less risk of over- or under-fitting compared to ML-EM. When MCLMC is run in parallel on a GPU, the samples can converge to the posterior distribution in about 10 seconds for an image with $10^3$--$10^4$ pixels, which is significantly faster than other comparable Markov Chain Monte Carlo (MCMC) samplers. We also tested MCLMC on a dataset from a real distributed source radiological mapping campaign, and the reconstructed results agree well with ground truth. The fast MCLMC sampler therefore enables improved imaging accuracy and prompt uncertainty quantification for reconstructed radiation images, which can better inform decision-making in response to radiological events.
title Radiological mapping and uncertainty quantification by a fast Microcanonical Langevin Monte Carlo sampler
topic Medical Physics
Instrumentation and Detectors
url https://arxiv.org/abs/2602.16991