OBJECTIVES: To assess the currently applied CT image acquisition protocols in lung cancer screening (LCS) and thereby fill a knowledge gap to support guideline development. MATERIALS AND METHODS: Through worldwide distribution of an online survey, data on institutional and technical factors regarding CT acquisition protocols in LCS were collected between 06/2024 and 09/2025 on behalf of the SOLACE (Strengthening the screening of lung cancer in Europe) consortium. RESULTS: Global responses were received from 71 LCS institutions across 29 countries (all continents). Responsibility for CT protocol establishment and modification varied among professions (radiologists, radiographers, medical physicists, and manufacturer personnel). Protocol establishment was dominated by radiologists (64 of 115), with only one-third of institutions involving multiple professions. Technical questions were partially answered. Automatic exposure control was implemented in 88% of centers (43 of 49). Reconstructed slice thickness ranged from 0.625 to 1.5 mm, with 1.0 mm being most common (43 of 67). Increment ranged between 0.5 and 1.25 mm. Software support for LCS was used by 90% of respondents (35 of 39), primarily for nodule detection (92%), volumetry (89%), and calculation of volume doubling time (71%). Image reconstruction was dominated by iterative reconstruction with statistical modeling (30) or deep learning support (7), while filtered-back projection was marginally used (4). CONCLUSIONS: Lung cancer screening often pushes current device limits, which warrants a multiprofessional establishment of CT protocols. Variability in reconstruction calls for further study on the effects on volumetry. Optimizing protocols remains crucial to balance radiation dose reduction and diagnostic accuracy in guideline development. CRITICAL RELEVANCE STATEMENT: This international study evaluates current CT image acquisition protocols in lung cancer screening and implications for guidelines, highlighting insufficient multiprofessional engagement for protocol definition and pronounced variability in technical parameters, both of which demand harmonization to inform robust guideline development. KEY POINTS: Variability of CT acquisition protocols impacts lung cancer screening. International survey results shed light on currently applied protocols. The narrowed knowledge gap supports guideline recommendations and standardization.
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