Adaptive scan duration in SPECT: Evaluation for radioembolization.

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiopharmaceutical Therapy

Background:

• Selecting optimal scan durations for single-photon emission computed tomography (SPECT) is challenging due to variable activity distribution.
• Current SPECT protocols often use fixed scan times, potentially leading to inefficiencies.
• Personalizing scan duration based on real-time data could improve SPECT protocol efficiency.

Purpose of the Study:

• To investigate the feasibility of optimizing SPECT scan duration per scan using real-time activity distribution evaluation, termed adaptive scanning.
• To assess adaptive scanning for detecting extrahepatic depositions in radioembolization pretreatment.
• To determine if adaptive scanning can reduce scan times without compromising diagnostic accuracy.

Main Methods:

• Adaptive scanning was evaluated using simulations and experiments for 99mTc-labeled macroaggregated albumin (99mTc-MAA) SPECT.
• Scans were terminated based on criteria: <5% mask difference or <0.075% negligible extrahepatic activity.
• Performance was assessed using digital and physical phantoms, and simulations from 129 patient datasets.

Main Results:

• Adaptive scanning significantly reduced mean scan duration from 20 minutes to 4.8 ± 0.2 minutes across patient distributions.
• Scan termination times varied based on activity distribution characteristics.
• Detection accuracy for extrahepatic depositions remained unaffected, with a mean difference of 7.0 ± 1.0% compared to standard 20-minute scans.

Conclusions:

• SPECT scan duration can be personalized using adaptive scanning for radioembolization pretreatment, improving efficiency.
• The adaptive scanning approach shows potential for other SPECT protocols where a specific measure of interest can be optimized.
• This personalized approach enhances SPECT imaging by tailoring scan duration to individual patient needs and activity distributions.