Science to Practice: Enhancing Photothermal Ablation of Colorectal Liver Metastases with Targeted Hybrid Nanoparticles

Abstract

Image-guided percutaneous thermal ablation has been one of the principal tools in management of unresectable liver malignancies, including colorectal liver metastases (CRLM) ( 1 ). Currently, however, this technique is suitable mainly for tumors less than 4-5 cm in diameter and also results in incomplete ablation at tumor margins ( 2 ). To solve these problems, efforts have been made to combine thermal ablation with other treatment options, such as systemic and intra-arterial administration of therapeutics ( 3 - 5 ). In this issue of Radiology, White et al ( 6 ) introduced their work on development of an alternative approach by using biofunctionalized hybrid magnetic gold nanoparticles (HNPs) as catalysts for photothermal ablation of CRLM. They found that (a) the targeted (anti-MG1) HNPs are noncytotoxic and have greater than 20% intratumoral accumulation and (b) systemic administration of anti-MG1 HNPs can enlarge a tumor's necrotic zone with photothermal ablation. The results of this study establish the proof of the concept that targeted HNPs can enhance the therapeutic effect of photothermal ablation, which presents an exciting strategy for complete removal of CRLM by integrating two rapidly advancing scientific fields-interventional radiology and nanotechnology.

Multi-fiber distributed thermal profiling of minimally invasive thermal ablation with scattering-level multiplexing in MgO-doped fibers

“…Four principal methods have been implemented in clinical practice: radiofrequency ablation (RFA), which makes use of the difference of potential between an active electrode positioned on the applicator tip and a passive electrode placed in a neutral spot [1,6]; microwave ablation (MWA) uses a generator emitting around 2.4 GHz to deliver an alternate power to the tissue, which acts as an electrical load [9]; laser ablation (LA), in which a solid-state laser delivers a continuous power to the tissue through one or multiple delivery fibers [7]; high-intensity focused ultrasound (HIFU), a non-contact method, in which an arrayed element focuses an ultrasound beam scanning the target tissue [10]. Among these methods, RFA and MWA have been appreciated for their capability to treat wide portions of tissue and rapid ablation process, and recent results show that these methods can be complemented with nanoparticles to extend the ablated tissue by a significant amount [11].…”

Temperature Profiling of ex-vivo Organs during Ferromagnetic Nanoparticles-Enhanced Radiofrequency Ablation by Fiber Bragg Grating Arrays

“…2(a). The duration of the experiment is 172 s and is longer than previous ablation; this is in part due to the effect of the ferromagnetic material, that by reducing the average impedance [14] during the most intense RFA heating prevents early disconnections of the RFA power, with the consequence that the heat is delivered to the peripheral regions in a much deeper way.…”

“…Overall, the use of NP introduced in situ within the tissue alters the electrical impedance and the heat conductivity of the tissue, depending on their density and position [12]. Previous studies [13,14] show that NP-mediated ablation has a better capacity of delivering heat to the peripheral sides of the tumors.…”