Stereotactic Body Radiotherapy for Ventricular Tachycardia (CARDIAC SBRT)

1. Cardiac Magnetic Resonance Imaging (MRI) with IV Gadolinum within 14 days of enrolment at the Princess Alexandra Hospital (PAH) Radiology department to assess patient's heart. This will take approximately 30 mins. Assessment by the cardiologist, radiologist and treating Radiation Oncologist (RO) at PAH. This may be done on the same day as the PET Scan. 2. MRI 48 hours, 3 months and 12 months post completion of Stereotactic Body Radiotherapy (SBRT) to assess local oedema, any acute injury such as pericardial effusion and evaluate late fibrotic changes. Assessment carried out by cardiologists at the PAH. Each scan will take approximately 30mins. 3. Positron Emissions Testing (PET) within 14 days of enrollment at the PAH Radiology Department to identify areas of inflammation and ischaemia to assist in the delineation of the proposed SBRT treatment volume assessed by cardiologists, radiologists and treating RO. This scan will take approximately 1 hour and may be done on the same day as the Cardiac MRI. 4. Planning for the SBRT. This involves the patient attending the Radiation Oncology Department at the PAH. The patient will positioned on a robotic bed, and may be asked to lie on a special bean bag. When the air is removed from the bean bag, this creates a mould around the patient to assist the patient in keeping still during the planning and treatment. This is so that the patient is in the same position as when the treatment is planned. Whilst lying in this bean bag, a special machine called an MRI-Sim will take a Computerised Tomography (CT) Scan and MRI to assist in the delineation of the proposed SBRT Treatment volume by the treating RO. This process will take approximately 1 hour. 5. The SBRT treatment delivered at the PAH radiation therapy unit by Qualified Radiation therapists and is usually about 5-7 days after the planning session. The patient will lie on a robotic bed in the same position as the planning session and will be moved under a machine called a linear accelerator. This machine produces high energy xrays to deliver the SBRT treatment directed at the heart. The patient needs lie very still whilst the having the treatment however there is nothing to see or feel when the treatment is being given. The radiation therapists will move the linear accelerator around the patient to deliver multiple xray beams from different angles to ensure the entire area receives the prescribed treatment dose. The whole process may take a little under one hour, however the actual time the linear accelerator is delivering xrays may only be a few seconds from each angle. The dose prescribed for this treatment is 25Gy given in one single treatment. 6. Evaluation of ICD immediately using electrocardiograms (ECG) before and immediately after SBRT will assess any immediate side effects of the treatment. This involves having electrodes placed on the chest to record the heart's electrical signals. This will be conducted by the cardiologists at the PAH and will take approx 30 minutes each.