Retrospective study of dynamic imaging acquisition length optimisation for sentinel lymph node scans

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Current sentinel lymph node (SLN) scan protocols recommend immediate dynamic imaging post-injection.
• Optimal dynamic acquisition duration for SLN scans remains underexplored, lacking specific guidance.

Purpose of the Study:

• To identify the optimal dynamic imaging duration for SLN scans by determining when no new SLNs are detected.
• To assess the impact of a 20-minute imaging protocol on clinical interpretation compared to standard-of-care imaging.

Main Methods:

• Retrospective review of 106 SLN dynamic acquisitions across five primary cancer sites.
• Independent expert review to determine the time-point of no further SLN detection and compare 20-minute vs. full-duration protocols.
• Survey of current SLN scan dynamic imaging practices.

Main Results:

• No new sentinel lymph nodes (SLNs) were detected after 25 minutes in any study.
• A 20-minute dynamic protocol identified the same SLNs as the full acquisition duration.
• Interobserver agreement among expert reporters was high (0.82).
• Survey data indicated a median current dynamic scan duration of 15 minutes.

Conclusions:

• A 25-minute dynamic scan captures all SLNs, but a 20-minute protocol is unlikely to alter image reporting.
• Implementing a 20-minute dynamic imaging protocol for SLN scans can decrease clinical workload and enhance patient comfort.
• The study suggests a 20-minute dynamic acquisition is a viable alternative without compromising diagnostic outcomes.