Optimisation of non-contrast CT examinations using tin (Sn) filtration: A systematic review

This systematic review explores the impact of Tin (Sn) filtration on radiation dose and image quality improvement in CT.

Using the PICO (Population, Intervention, Comparison, Outcome) framework, the research question was developed: How does the application of Sn filtration as part of an optimisation strategy affect clinical outcomes related to radiation dose and image quality? MeSH search terms derived from this question were input into five databases: PUBMED, Scopus, CINAHL Complete, Cochrane Central, and ProQuest Health & Medical Collection. Studies were independently screened by three experts using PRISMA guidelines. Inclusion criteria focused on adult clinical studies using Sn filtration in non-contrast CT scans alongside iterative reconstruction (IR). Risk of bias was assessed using the JBI critical appraisal tool.

A final 39 studies were included for evaluation. Sn with IR was used to optimise scanning in 10 different types of CT examinations. The use of Sn with IR resulted in a significant dose reduction (20-95 %) across all examinations. Most studies did not compare Sn with IR optimised examinations against standard examinations (without Sn) using a consistent, pre-set noise level, and reported an increase in image noise.

Sn is an effective dose reduction strategy for non-contrast CT examinations, but its limitations in terms of objective image quality warrant careful consideration by adjusting the IR level. Further studies are needed to confirm this approach.

The findings support broader consideration of Sn filtration beyond its current use in a single CT vendor. However, wider adoption may face barriers such as vendor-specific hardware limitations, cost, and the need for training and protocol optimisation in clinical practice.