Proof of concept percutaneous treatment system to enable fast and finely controlled ablation of biological tissue

On the effects of 30.5 GHz sinusoidal wave exposure on glioblastoma organoids

Introduction

Glioblastoma (grade IV) is the most aggressive primary brain tumor in adults, representing one of the biggest therapeutic challenges due to its highly aggressive nature. In this study, we investigated the impact of millimeter waves on tridimensional glioblastoma organoids derived directly from patient tumors. Our goal was to explore novel therapeutic possibilities in the fight against this challenging disease.

Methods

The exposure setup was meticulously developed in-house, and we employed a comprehensive dosimetry approach, combining numerical and experimental methods. Biological endpoints included a global transcriptional profiling analysis to highlight possible deregulated pathways, analysis of cell morphological changes, and cell phenotypic characterization which are all important players in the control of glioblastoma progression.

Results and discussion

Our results revealed a significant effect of continuous millimeter waves at 30.5 GHz on cell proliferation and apoptosis, although without affecting the differentiation status of glioblastoma cells composing the organoids. Excitingly, when applying a power level of 0.1 W (Root Mean Square), we discovered a remarkable (statistically significant) therapeutic effect when combined with the chemotherapeutic agent Temozolomide, leading to increased glioblastoma cell death. These findings present a promising interventional window for treating glioblastoma cells, harnessing the potential therapeutic benefits of 30.5 GHz CW exposure. Temperature increase during treatments was carefully monitored and simulated with a good agreement, demonstrating a negligible involvement of the temperature elevation for the observed effects. By exploring this innovative approach, we pave the way for improved future treatments of glioblastoma that has remained exceptionally challenging until now.

Microwave ablation of ex vivo human liver and colorectal liver metastases with a novel 14.5 GHz generator

PURPOSE

This study assessed the relationship between time, power and ablation size using a novel high-frequency 14.5 GHz microwave applicator in ex vivo human hepatic parenchyma and colorectal liver metastases. Previous examination has demonstrated structurally normal but non-viable cells within the ablation zone. This study aimed to further investigate how ablation affects these cells, and to confirm non-viability.

MATERIALS AND METHODS

Ablations were performed in ex vivo human hepatic parenchyma and tumour for a variety of time (10-180 s) and power (10-50 W) settings. Histological examination was performed to assess cellular anatomy, whilst enzyme histochemistry was used to confirm cellular non-viability. Transmission electron microscopy was used to investigate the subcellular structural effects of ablation within these fixed cells. Preliminary proteomic analysis was also performed to explore the mechanism of microwave cell death.

RESULTS

Increasing time and power settings led to a predictable and reproducible increase in size of ablation. At 50 W and 180 s application, a maximum ablation diameter of 38.8 mm (±1.3) was produced. Ablations were produced rapidly, and at all time and power settings ablations remained spherical (longest:shortest diameter <1.2). Routine histological analysis using haematoxylin-eosin (H&E) confirmed well preserved cellular anatomy despite ablation. Transmission electron microscopy demonstrated marked subcellular damage. Enzyme histochemistry showed complete absence of viability in ablated tissue.

CONCLUSIONS

Large spherical ablation zones can be rapidly and reproducibly achieved in ex vivo human hepatic parenchyma and colorectal liver metastases using a 14.5 GHz microwave generator. Despite well preserved cellular appearance, ablated tissue is non-viable.

Interventional navigation systems for treatment of unresectable liver tumor

Most patients with liver tumors are not candidates for surgical resection. A number of local treatment methods for unresectable liver tumors have recently received considerable interests. The major task of these procedures is accurate needle placement with the aim of complete tumor removal and minimal damage to surrounding normal liver parenchyma. In this article, we review the current status of interventional navigation system (INS) for treatment of unresectable liver tumors in terms of overall workflow, tracking systems, and research development. The conceptual design of INS consists of pre-operative and intra-operative modules. The tracking system falls into three types: optical, electromagnetic, and MR gradient based. The current INS, according to their image modalities, can be classified into four categories: MRI based, CT based, U/S based, and multimodalities based. The article also discusses the future research direction for enhanced performance of INS with real time imaging, high accuracy, high resolution, and friendly user-interface.