Treatment of intrahepatic malignancy with radiofrequency ablation

Abstract

RF ablation is a minimally invasive and safe approach to the treatment of tumors in the liver. Tumors treated with RF energy do not immediately demonstrate coagulative necrosis, but do show evidence of irreversible cellular damage. The extent of tumor necrosis correlates closely with findings at contrast-enhanced imaging.

Experimental characterisation of the thermal lesion induced by microwave ablation

“…At first, by relating the data reported in Table II with a visual analysis of the zone of ablation (Figure 4), the following considerations can be made: the light red colour zone observed in the peripheral area of the lesion (15 mm5r518 mm), which is usually defined a congestive zone [31,32], can be related to heating at mid-range temperatures (53-62 C); the grey-white colour zone (6 mm5r515 mm), which is associated with the ablated area, corresponds to heating at higher temperatures (62-98 C); the central burnt area, close to the tip of the antenna (r56 mm), is the coagulative region where temperatures higher than 100 C were reached and tissue charring occurred. Moreover, the proposed methodology being simple, it could be used to increase the amount of available data on dielectric properties' dependence on the temperature, both with reference to the considered liver tissue and with reference to other normal as well as pathological tissues [33].…”

Ablative therapy for liver tumours

“…A 14 to 21 gauge perfusion electrode needle with a cooled exposed tip, chilled to −5°C by internal water irrigation, is placed in the tumour under US or CT image guidance. [20][21][22][23] The advantage of this arrangement is that the duration of the ablation, and therefore both the energy delivered and lesion size obtained, is increased because no tissue charring occurs around the cooled needle tip. 24 Alternating electric current in the range of radiofrequency (RF) waves (460 kHz) is applied from an RF generator.…”

“…26 Treatment of hepatic tumours by RFA was assessed with radiological-pathological follow up by Goldberg and colleagues. 22 Twenty three tumours (all <8 cm, both CRC metastases and HCCs) were treated with RFA. Needle insertion was performed using CT or US guidance, percutaneously or intraoperatively.…”

Microwave ablation ofex vivohuman liver and colorectal liver metastases with a novel 14.5 GHz generator

“…Much attention has focused on radiofrequency ablation (RFA) and there is now growing clinical evidence to support the use of ablation for the treatment of irresectable lesions [1][2]. RFA relies on current transmission, and tissue desiccation and charring can lead to an exponential increase in tissue impedance causing unpredictable ablation size and a maximum theoretical size of ablation that can be achieved [3]. Current work investigating RF antennas with a cooling mechanism aims to overcome this obstacle by reducing the desiccation of tissue immediately around the antenna, allowing the creation of a larger electric pole and improving electrical conductivity within tissue leading to larger ablation zones [4][5].…”