Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis

PurposeMagnetic particle imaging (MPI) is a nascent tracer imaging modality that generates images from magnetic iron oxide nanoparticles (MIONs) in tissue. MPI resolution is a critical input parameter for defining the reliability of simulations-based temperature predictions for magnetic nanoparticle...

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Main Authors: Shreeniket Pawar, Nageshwar Arepally, Hayden Carlton, Joshua Vanname, Robert Ivkov, Anilchandra Attaluri
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-02-01
Series:Frontiers in Thermal Engineering
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Online Access:https://www.frontiersin.org/articles/10.3389/fther.2025.1520951/full
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author Shreeniket Pawar
Nageshwar Arepally
Hayden Carlton
Joshua Vanname
Robert Ivkov
Robert Ivkov
Robert Ivkov
Robert Ivkov
Anilchandra Attaluri
author_facet Shreeniket Pawar
Nageshwar Arepally
Hayden Carlton
Joshua Vanname
Robert Ivkov
Robert Ivkov
Robert Ivkov
Robert Ivkov
Anilchandra Attaluri
author_sort Shreeniket Pawar
collection DOAJ
description PurposeMagnetic particle imaging (MPI) is a nascent tracer imaging modality that generates images from magnetic iron oxide nanoparticles (MIONs) in tissue. MPI resolution is a critical input parameter for defining the reliability of simulations-based temperature predictions for magnetic nanoparticle hyperthermia (MNPH). The objective of this study was to ascertain how spatial resolution provided by MPI data affects the reliability of predicted temperatures and thermal dose in simulations using MPI data as inputs.MethodsComputed tomography (CT) and MPI scans obtained from a tumor injected with MIONs were co-registered to align their coordinates. Co-registered data were used to obtain geometry and volumetric heat sources for computational simulations of MNPH in phantom tumors. In addition to using the MPI-derived in vivo MION distribution (D1) we analyzed two mathematical MION distributions: uniform (D2) and Gaussian (D3). All distributions were discretized into cubic voxels and the data were imported into a commercial finite element bioheat transfer (FEBHT) software for thermal simulations. FEBHT simulations were conducted using the Pennes’ bioheat equation using four different MION specific loss power (SLP) values in the range 300–600 [W/g Fe]. The impact on predicted temperature resolution and thermal dose of spatial resolution were assessed by varying the linear voxel density (LVD) from 0.36 to 4.06 [voxel/mm]. Results were compared against the simulation with the highest LVD [4.06(voxel/mm)], where deviations in temperature of ≤ ±1 [°C] and thermal dose coverage ≤ ±5 [%] were deemed acceptable.ResultsThe D3 distribution resulted in the highest predicted temperatures, followed by D1 and D2; however, in terms of thermal dose, D1 showed lowest tumor coverage, requiring higher heat output from MIONs than was required for the other distributions studied. The results of the sensitivity analysis revealed that the predicted tumor temperature increased with LVD across all tested SLP values. Additionally, we observed that the minimum acceptable LVD increased with SLP.ConclusionCurrent (preclinical small animal) MPI scanners provide sufficient spatial resolution to predict temperature to within ±1 [°C], and thermal dose coverage to within ±5 [%] for MION formulations having heat output SLP = <370 [W/g Fe]. Higher spatial resolution is needed to achieve a similar precision when MION SLP exceeds 370 [W/g Fe]. We also conclude from the results that assuming a uniform MION distribution in tissue, which has been a common practice in MNPH simulations, overestimates the SLP needed to deposit meaningful thermal dose.
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spelling doaj-art-775af09fec89404183e3cd16a2d584142025-08-20T02:43:12ZengFrontiers Media S.A.Frontiers in Thermal Engineering2813-04562025-02-01510.3389/fther.2025.15209511520951Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysisShreeniket Pawar0Nageshwar Arepally1Hayden Carlton2Joshua Vanname3Robert Ivkov4Robert Ivkov5Robert Ivkov6Robert Ivkov7Anilchandra Attaluri8Department of Mechanical Engineering, School of Science, Engineering, and Technology, The Pennsylvania State University Harrisburg, Harrisburg, PA, United StatesDepartment of Mechanical Engineering, School of Science, Engineering, and Technology, The Pennsylvania State University Harrisburg, Harrisburg, PA, United StatesDepartment of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United StatesDepartment of Mechanical Engineering, School of Science, Engineering, and Technology, The Pennsylvania State University Harrisburg, Harrisburg, PA, United StatesDepartment of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United StatesDepartment of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, United StatesDepartment of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United StatesDepartment of Materials Science and Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United StatesDepartment of Mechanical Engineering, School of Science, Engineering, and Technology, The Pennsylvania State University Harrisburg, Harrisburg, PA, United StatesPurposeMagnetic particle imaging (MPI) is a nascent tracer imaging modality that generates images from magnetic iron oxide nanoparticles (MIONs) in tissue. MPI resolution is a critical input parameter for defining the reliability of simulations-based temperature predictions for magnetic nanoparticle hyperthermia (MNPH). The objective of this study was to ascertain how spatial resolution provided by MPI data affects the reliability of predicted temperatures and thermal dose in simulations using MPI data as inputs.MethodsComputed tomography (CT) and MPI scans obtained from a tumor injected with MIONs were co-registered to align their coordinates. Co-registered data were used to obtain geometry and volumetric heat sources for computational simulations of MNPH in phantom tumors. In addition to using the MPI-derived in vivo MION distribution (D1) we analyzed two mathematical MION distributions: uniform (D2) and Gaussian (D3). All distributions were discretized into cubic voxels and the data were imported into a commercial finite element bioheat transfer (FEBHT) software for thermal simulations. FEBHT simulations were conducted using the Pennes’ bioheat equation using four different MION specific loss power (SLP) values in the range 300–600 [W/g Fe]. The impact on predicted temperature resolution and thermal dose of spatial resolution were assessed by varying the linear voxel density (LVD) from 0.36 to 4.06 [voxel/mm]. Results were compared against the simulation with the highest LVD [4.06(voxel/mm)], where deviations in temperature of ≤ ±1 [°C] and thermal dose coverage ≤ ±5 [%] were deemed acceptable.ResultsThe D3 distribution resulted in the highest predicted temperatures, followed by D1 and D2; however, in terms of thermal dose, D1 showed lowest tumor coverage, requiring higher heat output from MIONs than was required for the other distributions studied. The results of the sensitivity analysis revealed that the predicted tumor temperature increased with LVD across all tested SLP values. Additionally, we observed that the minimum acceptable LVD increased with SLP.ConclusionCurrent (preclinical small animal) MPI scanners provide sufficient spatial resolution to predict temperature to within ±1 [°C], and thermal dose coverage to within ±5 [%] for MION formulations having heat output SLP = <370 [W/g Fe]. Higher spatial resolution is needed to achieve a similar precision when MION SLP exceeds 370 [W/g Fe]. We also conclude from the results that assuming a uniform MION distribution in tissue, which has been a common practice in MNPH simulations, overestimates the SLP needed to deposit meaningful thermal dose.https://www.frontiersin.org/articles/10.3389/fther.2025.1520951/fullmagnetic nanoparticle hyperthermiamagnetic particle imagingmagnetic iron oxide nanoparticlecomputed tomographyfinite element analysisbioheat transfer simulation
spellingShingle Shreeniket Pawar
Nageshwar Arepally
Hayden Carlton
Joshua Vanname
Robert Ivkov
Robert Ivkov
Robert Ivkov
Robert Ivkov
Anilchandra Attaluri
Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
Frontiers in Thermal Engineering
magnetic nanoparticle hyperthermia
magnetic particle imaging
magnetic iron oxide nanoparticle
computed tomography
finite element analysis
bioheat transfer simulation
title Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
title_full Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
title_fullStr Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
title_full_unstemmed Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
title_short Magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning: a sensitivity analysis
title_sort magnetic particle imaging resolution needed for magnetic hyperthermia treatment planning a sensitivity analysis
topic magnetic nanoparticle hyperthermia
magnetic particle imaging
magnetic iron oxide nanoparticle
computed tomography
finite element analysis
bioheat transfer simulation
url https://www.frontiersin.org/articles/10.3389/fther.2025.1520951/full
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