State-of-the-art and future developments in dosimetry for SSTR- and PSMA-targeting radioligand therapies.

Radioligand therapy targeting the prostate-specific membrane antigen (PSMA) or somatostatin receptors (sstr) has become an established treatment option for metastatic castration-resistant prostate cancer and advanced or inoperable neuroendocrine tumours, respectively. Although several studies have already demonstrated the clinical usefulness of dosimetry-guided personalized treatment schedules, and although there is growing evidence for absorbed-dose-effect-relationships, the clinical implementation of personalized dosimetry is slow due to various factors, such as logistical constraints, a lack of standardisation or missing reimbursement. This review highlights current and future developments in quantitative imaging and personalized dosimetry for radioligand therapy. Current challenges, such as improving the accuracy and efficiency of quantitative imaging, imaging of alpha emitters, single-time-point dosimetry and PET-based absorbed dose prediction, microdosimetry and radiobiology, will be considered. Further, this review will address current ideas on how to implement dosimetry-guided treatment planning for radioligand therapy.