Experimental ex-vivo validation of PMMA-based bone cements loaded with magnetic nanoparticles enabling hyperthermia of metastatic bone tumors

Mariem Harabech,Wim Maenhoudt,Dirk Van Roost,Normunds Rungevics Kiselovs,Luc Dupré,Guillaume Crevecoeur

doi:10.1063/1.4973499

Mariem Harabech, Wim Maenhoudt + Show 4 more

Open Access

https://doi.org/10.1063/1.4973499

Copy DOI

Journal: AIP Advances	Publication Date: Dec 27, 2016
Citations: 11	License type: CC BY 4.0

Affiliation: Ghent University, Ghent University Hospital

Abstract

Percutaneous vertebroplasty comprises the injection of Polymethylmethacrylate (PMMA) bone cement into vertebrae and can be used for the treatment of compression fractures of vertebrae. Metastatic bone tumors can cause such compression fractures but are not treated when injecting PMMA-based bone cement. Hyperthermia of tumors can on the other hand be attained by placing magnetic nanoparticles (MNPs) in an alternating magnetic field (AMF). Loading the PMMA-based bone cement with MNPs could both serve vertebra stabilization and metastatic bone tumor hyperthermia when subjecting this PMMA-MNP to an AMF. A dedicated pancake coil is designed with a self-inductance of 10 μH in series with a capacitance of 0.1 μF that acts as resonant inductor-capacitor circuit to generate the AMF. The thermal rise is appraised in beef vertebra placed at 10 cm from the AMF generating circuit using optical temperatures sensors, i.e. in the center of the PMMA-MNP bone cement, which is located in the vicinity of metastatic bone tumors in clinical applications; and in the spine, which needs to be safeguarded to high temperature exposures. Results show a temperature rise of about 7 °C in PMMA-MNP whereas the temperature rise in the spine remains limited to 1 °C. Moreover, multicycles heating of PMMA-MNP is experimentally verified, validating the technical feasibility of having PMMA-MNP as basic component for percutaneous vertebroplasty combined with hyperthermia treatment of metastatic bone tumors.

Highlights

In spinal metastatic tumor disease, the vertebral body is invaded and weakened by pathological tissue, which can lead to the collapse of the vertebral body and a progressive compression of the spinal cord
A temperature increase in T 1 is attained of approximately T max = 7 ◦C above the initial temperature T 0 when having an alternating magnetic field (AMF) applied during 14 min using the pancake coil with excitation current I = 200 A, whereas the increase of the temperature in the spine T 2 does not exceed 1 ◦C
A dedicated pancake coil of 8 turns with an outer radius of 13 cm was designed, having an inductance of L = 10 μH and was placed in series with C = 0.1 μF capacitors resulting in a resonance frequency of 160 kHz

Summary

Introduction

In spinal metastatic tumor disease, the vertebral body is invaded and weakened by pathological tissue, which can lead to the collapse of the vertebral body and a progressive compression of the spinal cord. This in turn may lead to a severe neurological function deficit. Vertebral body augmentation by the injection of “cement” (polymethylmetacrylate, PMMA),[1] so-called vertebroplasty (direct injection of PMMA with high pressure device) or kyphoplasty (making a cavity in the vertebral body with a balloon before filling it with PMMA at relatively low pressure) readily stabilizes the spine, but does not stop tumor progression.[2] Current spinal metastatic disease treatments, such as the standard and most common neurosurgery, radiofrequency ablation[3] and laser induced thermotherapy techniques[4] are performed before the injection of the cement and can be performed only once. The treatment should ideally be performed in a repetitive way, without additional invasive manipulations

Methods

Results

Conclusion