β-Radioluminescence Imaging: A Comparative Evaluation with Cerenkov Luminescence Imaging

Area of Science:

• Medical Imaging
• Radiochemistry
• Biophysics

Background:

• Cerenkov luminescence imaging (CLI) provides high-resolution images of (18)F-FDG-avid tumors.
• CLI's low photon sensitivity necessitates prolonged acquisition times.
• A new modality, beta-radioluminescence imaging (β-RLI), is proposed for imaging beta particles using a scintillator and gamma-rejection strategy.

Purpose of the Study:

• To comparatively evaluate the performance of β-RLI and CLI.
• To assess both modalities in vitro and in vivo using various tumor models.
• To determine the efficacy of β-RLI for imaging both amelanotic and melanotic tumors.

Main Methods:

• In vitro phantom studies to characterize photon sensitivity and resolution of CLI and β-RLI.
• In vivo experiments using xenograft mouse models with amelanotic (A375, UMSCC1-Luc) and melanotic (B16F10-Luc) cell lines.
• Correlation of (18)F-FDG activity (from PET) with tumor radiance for both modalities and comparison of signal-to-background ratios (SBRs).

Main Results:

• β-RLI demonstrated 560-fold greater photon sensitivity than CLI in vitro, though with lower spatial resolution (4.4 mm vs 1.0 mm).
• In vivo, β-RLI showed significant correlation between (18)F-FDG activity and tumor radiance (r=0.52, P<0.01).
• β-RLI achieved SBR > 1 for all lesions, outperforming CLI for melanotic tumors where 9 of 13 lesions had SBR < 1.

Conclusions:

• β-RLI enables functional imaging of both amelanotic and melanotic tumors in significantly shorter timeframes compared to CLI.
• The developed β-RLI modality shows potential for faster and more sensitive tumor imaging.
• Further engineering advancements are necessary to fully realize the clinical applicability of β-RLI.