The Role of SPECT/CT in 177 Lu-PSMA-617 Theranostics: Case-based Review of Response and Progression Patterns.

Lutetium-177 prostate-specific membrane antigen-617 (Lu-PSMA) has demonstrated efficacy in improving progression-free survival and overall survival in patients with metastatic castration-resistant prostate cancer (mCRPC). Post-treatment single photon emission tomography/computed tomography (SPECT/CT) imaging is an emerging tool for monitoring treatment response, enabling the tracking of functional changes during therapy. While quantitative SPECT analysis can predict patient outcomes, qualitative assessments are more practical and time-efficient in clinical settings. This case-based review examines treatment responses based on post-treatment SPECT/CT imaging, categorizing them into favorable response, progression, and mixed response patterns to improve interpretation and guide therapeutic adjustments, aiming to optimize management of mCRPC with Lu-PSMA therapy.