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ORIGINAL RESEARCH ARTICLE
A commissioning workflow for quantitative 177Lu SPECT/CT across different Siemens scanner–reconstruction configurations
Leonardo Lampertico1,2 ,
Gaia Muti2* ,
Claudia Carbonini2 ,
Chiara Romanò2 ,
Antonio Scarale3 ,
Claudio Rossetti3 ,
Paola Enrica Colombo2
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1 Physics Department, Faculty of Physics, University of Milan, Milan, Lombardy,
Italy
2 Medical Physics Department, ASST GOM Niguarda, Milan, Lombardy,
Italy
3 Nuclear Medicine Department, ASST GOM Niguarda, Milan, Lombardy,
Italy
ARNM, 026260029 https://doi.org/10.36922/ARNM026260029
Received: 26 June 2026 | Revised: 20 July 2026 | Accepted: 30 July 2026 | Published online: 20 August 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract
The accuracy of quantitative lutetium-177 single-photon emission computed tomography/computed tomography (¹⁷⁷Lu SPECT/CT) depends on the imaging system, acquisition protocol, reconstruction algorithm, and calibration strategy. This study aimed to develop and evaluate a practical commissioning workflow to optimize ¹⁷⁷Lu imaging across different commercial scanner–reconstruction configurations. Three Siemens workflows were evaluated: FLASH3D and xSPECT Quant on the Symbia Intevo Bold, and FLASH3D+ on the Symbia Pro.specta. A uniform phantom was used to assess image noise and derive calibration factors for the ordered-subset expectation maximization (OSEM)-based reconstructions. Recovery coefficients (RCs) were evaluated via an International Electrotechnical Commission/National Electrical Manufacturers Association phantom at various sphere-to-background ratios and modeled using a three-parameter logistic function for partial volume correction. Reconstruction parameters were optimized by jointly evaluating RC convergence and image noise, followed by quantitative validation using an anthropomorphic phantom. OSEM-based workflows showed a predictable dependence on equivalent iterations, yielding lower image noise. Conversely, xSPECT Quant exhibited complex parameter dependence and higher noise, but provided superior activity recovery—with RCs closer to unity—and the lowest quantification errors during validation. A reconstruction setting of two subsets and 30 iterations was selected for all workflows. For FLASH3D and FLASH3D+, this configuration provided RCs closest to unity while maintaining the coefficient of variation below the predefined 15% threshold. The same setting was adopted for xSPECT Quant to ensure methodological consistency despite its intrinsically higher image noise. This commissioning workflow provides a practical framework for local ¹⁷⁷Lu SPECT/CT optimization. Among the configurations, xSPECT Quant yielded higher recovery coefficients and lower quantification errors, albeit with increased noise. These findings highlight the need for locally optimized protocols for patient-specific dosimetry and do not establish the general superiority of any one reconstruction algorithm.
Keywords
Lutetium-177 single-photon emission computed tomography/computed tomography
Quantitative imaging
Recovery coefficients
Reconstruction algorithms
xSPECT Quant
Ordered-subset expectation maximization reconstruction
Calibration; Internal dosimetry
Funding
None.
Conflict of interest
The authors declare they have no competing interests.
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