A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy

Introduction and Purpose Radiopharmaceutical therapy (RPT) dosimetry can be challenging to perform due to sparse data measurements and variations in how the time activity curve (TAC) is determined. In this work, a single system of equations was theoretically derived to estimate the TAC. Methods A ph...

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Main Authors: Joseph Steiner, Brandon Nguyen, Farhad Jafari
Format: Article
Language:English
Published: SAGE Publishing 2024-09-01
Series:Molecular Imaging
Online Access:https://doi.org/10.1177/15353508241280015
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author Joseph Steiner
Brandon Nguyen
Farhad Jafari
author_facet Joseph Steiner
Brandon Nguyen
Farhad Jafari
author_sort Joseph Steiner
collection DOAJ
description Introduction and Purpose Radiopharmaceutical therapy (RPT) dosimetry can be challenging to perform due to sparse data measurements and variations in how the time activity curve (TAC) is determined. In this work, a single system of equations was theoretically derived to estimate the TAC. Methods A pharmacokinetic (PK) model was developed to estimate patient specific rate constants for a given set of body compartments. The PK model and an optimizer were numerically implemented to determine the rate constants and, using these physiologic data, to generate TACs and time integrated activities (TIAs) for 3 tissue systems from clinical data gathered in 5 patients. A fourth (aggregate) tissue compartment is added using conservation of activity considerations. Results Feasibility of the PK model was demonstrated by successfully generating TACs and TIAs for all patients in a manner comparable to existing methods in the literature. The data are compared to smaller sampling regimes. Differences between the 3- and 4-compartment models show that conservation of activity considerations should be part of TAC estimations. Conclusion The results here suggest a new paradigm in RPT in using the rate constants so identified as a diagnostic tool and as a vehicle to achieving individualized tumorcidal dose and/or the maximum tolerable dose to normal tissues.
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spelling doaj-art-6f1505ad4c6c496cbb2f0aa04cbe6dd82025-08-20T03:19:03ZengSAGE PublishingMolecular Imaging1536-01212024-09-012310.1177/15353508241280015A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical TherapyJoseph Steiner0Brandon Nguyen1Farhad Jafari2 Department of Radiology, , Chicago, IL, USA Department of Radiology, , Minneapolis, MN, USA Department of Radiology, , Minneapolis, MN, USAIntroduction and Purpose Radiopharmaceutical therapy (RPT) dosimetry can be challenging to perform due to sparse data measurements and variations in how the time activity curve (TAC) is determined. In this work, a single system of equations was theoretically derived to estimate the TAC. Methods A pharmacokinetic (PK) model was developed to estimate patient specific rate constants for a given set of body compartments. The PK model and an optimizer were numerically implemented to determine the rate constants and, using these physiologic data, to generate TACs and time integrated activities (TIAs) for 3 tissue systems from clinical data gathered in 5 patients. A fourth (aggregate) tissue compartment is added using conservation of activity considerations. Results Feasibility of the PK model was demonstrated by successfully generating TACs and TIAs for all patients in a manner comparable to existing methods in the literature. The data are compared to smaller sampling regimes. Differences between the 3- and 4-compartment models show that conservation of activity considerations should be part of TAC estimations. Conclusion The results here suggest a new paradigm in RPT in using the rate constants so identified as a diagnostic tool and as a vehicle to achieving individualized tumorcidal dose and/or the maximum tolerable dose to normal tissues.https://doi.org/10.1177/15353508241280015
spellingShingle Joseph Steiner
Brandon Nguyen
Farhad Jafari
A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
Molecular Imaging
title A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
title_full A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
title_fullStr A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
title_full_unstemmed A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
title_short A Pharmacokinetic Model Determination of Time Activity Curves in Radiopharmaceutical Therapy
title_sort pharmacokinetic model determination of time activity curves in radiopharmaceutical therapy
url https://doi.org/10.1177/15353508241280015
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