Analysis to a critical state of thermal field in microwave ablation of liver cancer influenced by large vessels

Abstract

To study the effect of large blood vessels on the temperature field in invasive microwave ablation, a finite element method was applied based on the convective-type boundary condition on the interface between tissues and blood flow. Whether a large blood vessel is outside of or involved in the lesion area will affect the 54 degrees C effective therapeutic area in different critical conditions. This paper drew the function diagraph on the distance between blood vessel and antenna with the diameter of the blood vessel and put forward the concept of effective therapy radius. It can be used to study the influence of large vessels on the external boundary of the coagulation area and can be used as a theoretical basis to help to decide whether to occlude the large vessels before microwave ablation therapy.

Protection of skin with subcutaneous administration of 5% dextrose in water during superficial radiofrequency ablation in a rabbit model

“…The 'heat sink' effect is also a drawback of RF ablation in the treatment of tumours and reduces the size of the ablative zone by vascular dispersal of the deposited heat energy via a rapid stream of low-temperature blood [26][27], Consequently, we hypothesised that subcutaneous perfusion with D5W, which simulates the 'heat sink effect' during RF ablation, might have a role in depriving the ablative area. However, in our study, the sizes of the ablative zones were similar among the groups, as assessed by CEUS examination.…”

Continuum Models for the Cooling Effect of Blood Flow on Thermal Ablation Techniques

“…Since, on the first steps of cryoablation, an open surgery was required due to large probe sizes and the risk of bleeding, RF ablation has gained wide acceptance as a minimally invasive technique and becomes the most widely used hyperthermia technique to treat liver cancer, see [2][3][4] and the references therein. Nowadays the cryogenic treatment has modern catheters that can be 2 mm maximum diameter with 90 cm flexible length and then it also belongs to the more recent area of study of the thermal therapies as well as the application of imaging, ultrasound, and laser modalities among others [5][6][7][8][9]. Although our data may be specific to RF ablation in the liver, the continuum models are probably valid for all thermal ablation energy sources and for other organs which are close to vessels.…”

Effects of repeated use and resterilization on structural and functional integrity of microwave ablation antennas

“…If 60 °C or above is reached instantaneously, rapid protein denaturation occurs, which is immediately cytotoxic and leads to coagulative necrosis (instantaneous thermal lesion) . The lesion boundary is usually characterized as an isothermal contour of 54°C +/-0.5°C (Nan, 2010). Above that temperature, the changes linked to protein dehydration induced in the tissue are irreversible, even if the tissue is allowed to return to the initial temperature (Lopresto, 2012).…”

“…Thermal ablation applications in humans include the treatment of primary and metastatic neoplasia of the liver (Simon, 2005;Ahmed, 2011;Veltri, 2012; and various other cancers (eg, lungs (Simon, 2005;Dupuy, 2009;Ahmed, 2011;, bones (Simon, 2005;Ahmed, 2011;Nazario, 2011;, breasts , thyroid gland , and kidneys (Simon, 2005;Ahmed, 2011;). Thermal ablation induces irreversible cellular injury by creating a focal high-temperature environment (> 54°C for at least 3 minutes or 60°C reached instantaneously) (Goldberg, 1996;Nan, 2010;Ahmed, 2011). Several thermal ablation methods exist,…”