Continuous, Preclinical Activity Reconstruction in ¹⁷⁷Lu-based Radiopharmaceutical Therapy Using a Sparse...

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiopharmaceutical Therapy

Background:

• Lutetium-177 (¹⁷⁷Lu)-based radiopharmaceutical therapy (RPT) shows promise for neuroendocrine and prostate cancers.
• Accurate radiation dose delivery to tumors while sparing organs-at-risk (OAR) is crucial due to patient variability.
• Current methods lack the temporal resolution to capture dynamic activity distribution.

Purpose of the Study:

• To develop a high temporal-resolution activity reconstruction method for preclinical cancer models.
• To enable real-time monitoring of ¹⁷⁷Lu activity in tumors and OAR.
• To improve the quality and safety of ¹⁷⁷Lu-based RPT.

Main Methods:

• A low-cost, sparse sensor network was developed using a priori tumor location data.
• The system was validated using a custom phantom and four mouse models bearing prostate cancer xenografts.
• ¹⁷⁷Lu activity was measured at multiple time points post-injection (10 min to 48 h).

Main Results:

• The system achieved high linearity (R² > 0.99) in reconstructing tumor and OAR activity compared to small-animal SPECT.
• Acquisition and reconstruction occurred at 1-minute resolution, over 30 times faster than conventional SPECT.
• This enabled capture of fast kinetics and near-continuous time-activity curves at reduced cost.

Conclusions:

• The developed system provides high temporal resolution for preclinical activity reconstruction.
• This technology can be adapted for clinical use to enhance ¹⁷⁷Lu-RPT.
• Frequent activity measurements will improve treatment efficacy and patient safety.