Assessing Immediate Post-Administration Pluvicto and Lutathera Kinetics with a High Temporal Resolution Electronic Dosimeter
Abstract
Purpose
To determine the feasibility of using a high temporal resolution electronic dosimeter (NetDose+, manufactured by ThermoScientific) for patient-specific pharmacokinetic data collection and analysis for the immediate post-administration time-period prior to discharge.
Methods
A NetDose+ dosimeter, an electronic dosimeter that reports cumulative dose in 5 minute intervals, was placed in a fixed position behind a patient couch for the duration of the administration and post-administration hold. The data was exported, normalized to the peak dose and the time-to-peak and doses relative to peak at various timepoints were determined. Additionally, the number of restroom uses, bladder accumulation time, and the relative dose rate drop following restroom use was determined by analyzing breaks in the reported dose trend where it is clear the patient left the room during the accumulation interval. Data is currently being collected using a dual-device set-up to minimize errors introduced by patient movement for a larger number of patients for both Pluvicto and Lutathera.
Results
Across thirteen Lutathera cases analyzed so far, the maximum interval dose occurred at 44.2 ± 10 minutes post-initiation of therapy, respectively. At the 60-minute and 240 minute post-initiation windows for Lutathera administration, the relative dose collected was 87.2% ± 6.1% and 56.6% ± 12.9% relative to the peak. The percent reduction in measured dose following each restroom break was 14% ± 6.5% with large variations between patients in both per-excretion reduction and total reduction over the full measurement interval.
Conclusion
The NetDose+ electronic dosimeter can be used to provide some patient-specific pharmacokinetic information about the uptake and clearance of radiopharmaceuticals. The data collected so far demonstrates a wide distribution of uptake and excretion rates between patients which could have health physics and dosimetry ramifications. Refinements to the data collection and analysis processes have been implemented for a larger cohort of patients.