Microwave, radiofrequency, and cryoablation are procedural modalities that utilize extreme thermal energy to induce cell apoptosis. Applicators/probes are guided using CT to the tumor tissue and emit the energy to achieve locoregional tumor treatment of lesions of a certain size (<3.0 cm for liver). The heat modalities include radiofrequency ablation (RFA) and microwave ablation (MWA). RFA involves electrical conduction through tissue, which generates resistive heating to achieve effect via thermal diffusion. Its cost-effectiveness makes it very popular worldwide; however, it is limited by tissue and thermal conductivity. MWA involves dielectric heating. The use of electromagnetic waves at frequencies of 900 to 2450 MHz causes intracellular water molecules to oscillate and produce heat. MWA is not dependent on tissue properties and heats faster in a larger volume. During cryoablation, the rapid expansion of argon gas achieves temperatures as low as -160 °C to freeze and destroy the tumor cells. Each procedure consists of 1 to 3 cycles of freezing and thawing per lesion. An advantage is that the ablation zone can be visualized real time with CT during treatment. In addition, cryoablation preserves collagenous structures; however, there is no coagulation effect and bleeding occurs more readily. If the targeted lesions are adjacent to delicate tissue structures such as bowel or the diaphragm, separation can be created by fluid hydrodissection or pneumoperitoneum with CO₂. A physical distance is created between the zone of ablation and the neighboring tissue to prevent collateral damage.