Related Experiment Video
Updated: Jul 5, 2026
A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy (PRRT): 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods
Published on: April 24, 2020
Limitations of Mono-Exponential Individual Fitting as a Reference Model for Single-Time-Point Dosimetry in
Fulki Fiarka1, Assyifa Rahman Hakim1, Indra Budiansah2
1Medical Physics and Biophysics, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia.
Mono-exponential individual fitting (Mono-IFIT) is not ideal for validating single-time-point (STP) renal dosimetry in [177Lu]Lu-PSMA-617 therapy. Population-based model selection with non-linear mixed-effects modelling (PBMS NLMEM) offers a better reference framework for STP method validation.
Area of Science:
- Nuclear Medicine
- Radiopharmaceutical Therapy
- Dosimetry
Background:
- Accurate dosimetry is crucial for effective [177Lu]Lu-PSMA-617 targeted radionuclide therapy.
- Single-time-point (STP) methods offer a simplified approach to dosimetry compared to multi-time-point methods.
- Validation of STP methods requires a reliable reference model for absorbed dose calculation.
Purpose of the Study:
- To evaluate mono-exponential individual fitting (Mono-IFIT) as a reference model for validating STP renal dosimetry in [177Lu]Lu-PSMA-617 therapy.
- To compare STP accuracy rankings derived from Mono-IFIT with those from population-based model selection using non-linear mixed-effects modelling (PBMS NLMEM).
Main Methods:
- Kidney biokinetic data from 500 virtual patients and 10 clinical patients were analyzed.
- Reference absorbed doses were calculated using both Mono-IFIT and PBMS NLMEM.
- Four STP methods (STPNLMEM, STPMLR, STPH, and STPM) were assessed at approximately 48 hours post-injection.
Main Results:
- PBMS NLMEM demonstrated a superior fit to renal time-activity data compared to Mono-IFIT.
- STP method performance rankings were highly dependent on the chosen reference model.
- STPNLMEM showed the closest agreement with the PBMS NLMEM reference, while other STP methods underestimated absorbed dose.
Conclusions:
- Mono-exponential individual fitting (Mono-IFIT) is not a suitable reference model for validating STP renal dosimetry in [177Lu]Lu-PSMA-617 therapy.
- Population-based model selection with non-linear mixed-effects modelling (PBMS NLMEM) provides a more appropriate reference framework.
- STPNLMEM demonstrated the best agreement with the PBMS NLMEM reference, supporting its potential for personalized [177Lu]Lu-PSMA-617 treatment.
