case studies

CT guided radiofrequency ablation.

Forgive me if you are familiar with the process of ablation, as it is a totally new experience for me. I was fortunate enough to be working at one of our mobile sites on a day where two ablation procedures were performed.

Background
“Radiofrequency ablation is a relatively new therapy for cancer in which tumours are destroyed using heat energy” (Williams, 2002).

Radiofrequency ablation can be successfully used to destroy tumours in the lung, liver and bone, with the massive advantage over surgery that the lesion can be accurately isolated, sparing the surrounding, healthy tissues.

Radiofrequency ablation is a useful treatment to use alongside the more traditional options of surgery and chemotherapy; however, it is not intended to replace these modalities. Chemotherapy, for example, is an established treatment, but can be ineffective in the treatment of large tumours, as the central portion of large tumours typically have poor blood flow resulting in the tumour becoming aggressive and prone to spreading. Radiofrequency ablation targets the centre of such lesions and when utilised alongside chemotherapy or radiation therapy it can improve patients’ response to treatment.

It was initially thought that radiofrequency ablation was only useful in the treatment of small tumours up to 4cm in size, but research has shown that tumours up to 16cm can be treated successfully.

Technique
The patient is sedated prior to the technique commencing. A needle is inserted through the skin and into the lesion using CT control. This is achieved using the biopsy mode on the Lightspeed CT unit. The Radiologist positions skin markers over the approximate area of interest and a group of images are acquired to localise the lesion more accurately. From these images, a central location, directly over the lesion and a slice either side can be set into the biopsy mode and can be rescanned a number of times until the needle is in the centre of the lesion. The examination time depends greatly on the position of the lesion and the skill of the Radiologist performing the procedure.
Once the needle is in a satisfactory location (ideally being in the centre of the lesion) the needle is swapped for an ablation needle, which is connected to a unit supplying the radiofrequency. The energy passing through the needle generates heat and it is the heat that destroys the cancerous cells.
It is a minimally invasive procedure only requiring a short stay in hospital. I found this whole experience to be unique and exciting.
If you have enjoyed this article you may like to visit www.cancerlynx.com/rftumour.html

Helen Jones

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