How is RFA performed?
1:48 AM | 
Posted by Dr.Ajay Upadhyay
Dr. Ajay Upadhyay
This technique has many similarities to CT-guided lung biopsy procedures. Throughout the world, lung RFA is commonly performed in a CT scanner suite. Patients undergo this procedure either under moderate sedation with pain relief or under general anesthesia. General anesthesia has the advantage of complete control over patient's breathing pattern and motion that helps to accurately place the RFA electrode within the tumor.
Radio frequency Ablation (RFA) Needle
One study comparing conscious sedation to general anesthesia did not show any major difference in tumor control or procedure related complication rates, however the number of patients in both groups was small . A survey of centers performing RFA for lung tumors indicated that conscious sedation is used more commonly than general anesthesia . During the procedure, tumor cells are destroyed by placing a needle (RFA electrode) within the center of the tumor. The RFA electrodes come in various shapes, length and thickness, depending on the manufacturer . The RFA electrodes are carefully placed into the center of the tumor undergoing ablation using the guidance of images in the CT suite. Multiple CT images are taken to confirm the safe placement of RFA electrodes, and to avoid adjacent vital organs.
Following placement, RFA electrodes are connected to an external RF generator. High-frequency alternating energy is then applied through the RF electrodes. This causes ionic agitation in tumor cells which raises tissue temperature. As the temperature increases above 45-50 degrees centigrade within the tumor, cellular proteins denature and cell structure disintegrates. This results in thermal coagulation in tumor cells, ultimately leading to tumor destruction. The entire RFA procedure session usually takes 3-4 hours or less. Following completion of therapy, RFA probes are withdrawn from the patient. Subsequently, patients are closely observed for any post procedural complications such as lung collapse. Following an uncomplicated RFA procedure, patients are discharged home mostly after overnight observation or rarely the same day.
Lung tissue characteristics may play a role in the effectiveness of RFA. The normal lung tissue surrounding the tumor is relatively resistant to heating due to its high electrical impedance (20, 21). Therefore, the heat energy created by RFA is preferentially deposited in the tumor facilitating higher temperatures. Also, large blood vessels (> 3 mm) near a tumor constantly cool the tissue due to the flowing blood that takes heat away from the area being treated, commonly known as the heat sink effect (14, 20). As a result, tumors in continuity with large blood vessels may be suboptimally treated with RFA. Some electrodes are believed to produce necrosis measuring up to 4-5 cm in diameter. This allows for the treatment of a 3 cm lesion and a 1 cm margin of normal lung. Tumors larger than 3 cm may require multiple electrodes to create overlapping tissue RFA zones.
One study comparing conscious sedation to general anesthesia did not show any major difference in tumor control or procedure related complication rates, however the number of patients in both groups was small . A survey of centers performing RFA for lung tumors indicated that conscious sedation is used more commonly than general anesthesia . During the procedure, tumor cells are destroyed by placing a needle (RFA electrode) within the center of the tumor. The RFA electrodes come in various shapes, length and thickness, depending on the manufacturer . The RFA electrodes are carefully placed into the center of the tumor undergoing ablation using the guidance of images in the CT suite. Multiple CT images are taken to confirm the safe placement of RFA electrodes, and to avoid adjacent vital organs.
Following placement, RFA electrodes are connected to an external RF generator. High-frequency alternating energy is then applied through the RF electrodes. This causes ionic agitation in tumor cells which raises tissue temperature. As the temperature increases above 45-50 degrees centigrade within the tumor, cellular proteins denature and cell structure disintegrates. This results in thermal coagulation in tumor cells, ultimately leading to tumor destruction. The entire RFA procedure session usually takes 3-4 hours or less. Following completion of therapy, RFA probes are withdrawn from the patient. Subsequently, patients are closely observed for any post procedural complications such as lung collapse. Following an uncomplicated RFA procedure, patients are discharged home mostly after overnight observation or rarely the same day.
Lung tissue characteristics may play a role in the effectiveness of RFA. The normal lung tissue surrounding the tumor is relatively resistant to heating due to its high electrical impedance (20, 21). Therefore, the heat energy created by RFA is preferentially deposited in the tumor facilitating higher temperatures. Also, large blood vessels (> 3 mm) near a tumor constantly cool the tissue due to the flowing blood that takes heat away from the area being treated, commonly known as the heat sink effect (14, 20). As a result, tumors in continuity with large blood vessels may be suboptimally treated with RFA. Some electrodes are believed to produce necrosis measuring up to 4-5 cm in diameter. This allows for the treatment of a 3 cm lesion and a 1 cm margin of normal lung. Tumors larger than 3 cm may require multiple electrodes to create overlapping tissue RFA zones.
