Computed tomography (CT) and ultrasonography (US) are commonly employed to guide positioning of radiofrequency electrodes within target tumors. However, this technique cannot be used when the tumor is detectable only by positron emission tomography (PET). In such cases, even the use of intraprocedural coregistered PET/CT will not prevent malpositioning of the electrode tip relative to a lesion visualized only on PET as a result of patient breathing and organ shifts during CT-guided electrode placement. The present report describes a single case of successful targeting and complete ablation of a lesion invisible on CT and US with the use of a method to visualize electrode tip positioning by PET.