MRI after magnetic drug targeting in patients with advanced solid malignant tumors

Abstract

The purpose of this study was to evaluate the ability of MRI to detect magnetic particle uptake into advanced solid malignant tumors and to document the extension of these tumors, carried out in the context of magnetic drug targeting. In a prospective phase I trial, 11 patients were examined with MRI before and after magnetic drug targeting. The sequence protocol included T1-WI and T2-WI in several planes, followed by quantitative and qualitative evaluation of the signal intensities and tumor extensions. In nine patients, a signal decrease was observed in the early follow-up (2-7 days after therapy) on the T2-weighted images; two patients did not show a signal change. The signal changes in T1-WI were less distinct. In late follow-up (4-6 weeks after therapy), signal within nine tumors reached their initially normal level on both T1-WI and T2-WI; two tumors showed a slight signal decrease on T2-WI and a slight signal increase on T1-WI. Within the surveillance period, tumor remission in 3 out of 11 patients was observed, and in 5 patients tumor growth had stopped. The remaining three patients showed significant tumor growth. There was no statistically significant correlation between signal change and response. MRI is a suitable method to detect magnetite particles, deposited at the tumor site via magnetic drug targeting. MRI is therefore eligible to control the success of MDT and to assess the tumor size after the end of therapy.

Many particle magnetic dipole–dipole and hydrodynamic interactions in magnetizable stent assisted magnetic drug targeting

“…MDT is a relatively safe and effective methodology for targeting drugs to a specific site in the body [3,4,5]. However, there are some significant limitations of MDT.…”

In vivo MR quantification of superparamagnetic iron oxide nanoparticle leakage during low‐frequency‐ultrasound‐induced blood–brain barrier opening in swine

“…The contrast agent is then measured directly, and drug delivery is determined based on its concentration on the contrast agent (12,13). The second method assesses therapeutic agent delivery to the brain more accurately, and SPIO nanoparticles have many advantages in this regard: (i) SPIO nanoparticles are biocompatible and can be degraded safely by macrophages/ microglia (14), whereas gadolinium leakage raises safety concerns related to neurotoxicity (15); (ii) SPIO nanoparticle surfaces can be modified to easily conjugate therapeutic agents (12,13); (iii) MRI techniques such as T 2 *-weighted imaging or transverse relaxation rate (R 2 ) maps can be used to quantify the iron concentration in tissues, making quantification of therapeutic agent delivery easier (12,13); (iv) SPIO nanoparticles have high spin-spin relaxivities and can generate high magnetic moments that can be actively manipulated by externally applied magnets, making them suitable for use with magnetic targeting (16,17). The above advantages makes the SPIO nanoparticles has the potential to serve a ''thernostic'' agent, which means that the diagnostic and therapeutic functions can be concurrently provided during drug-delivering process.…”

High Efficacy in Hyperthermia-associated with Polyphosphate Magnetic Nanoparticles for Oral Cancer Treatment

“…The biokinetics of nanomaterials depends on their size, shape, chemical composition, surface structure, solubility and aggregation capacity. These parameters can modify the cellular uptake, the accumulation at the target site in vivo and the possibility of causing tissue damage [37,38].…”