Radiofrequency Ablation

1. Principle

• High-frequency alternating current applied via an electrode(s) placed within the tissue generates ionic agitation as the ions attempt to change directions and follow the alternating current, thereby creating localised friction heat.

• Uses heat generated from ionic agitation inside the tissues after application of a RF current.

• The heat produces a rim of necrosis around a RFA needle.

2. Uses

1. Hepatocellular Cancers

1. Indications

• Tumors less than 3 cm size

• Away from the hepatic hilum

• Deep seated tumors

1. Contraindications

• 5 cm

• Multifocal tumors

• Tumors with major vessel invasion

• Tumors situated peripherally or near portal tracts

2. Breast Cancers

Localized breast cancers as an attempt for BCS

3. Lung Cancers

Tumors which are unresectable

4. Hepatic Mets

Primarily in colorectal CA mets 1 - 3 in number

3. Methods

1. Equipment

1. RFA Probe

Contains several needles which when extruded assume an umbrella like configuration

Uses 400 - 500 KHz AC current

Can produce a zone of necrosis with a diameter of 7 cm

2. RFA Generator

Generates RFA current between 400 - 500 KHz

1. Method

Imaging of the tumor to determine extent

Sedation and analgesia

Probe insertion under LA / GA

deployment of needles

Application of RFA energy

Removal while sealing the tract with heat

3. Grounding Pads

Allow an electrical circuit to form with patient and the RFA needle

4. Disadvantages

Cant be used for larger or multiple tumors

Regional failure can occur

Cant be used for tumors close to major vessels or nerves

Requires special imaging guidance and planning

Expense of needle

5. Advantages

Minimally invasive procedure - can be done percutaneously

Minimal pain

Time 20 - 30 min

Good control of the necrosis area

Can be repeated multiple times

04/11/2007 1/2