Inclusion Criteria:

- R0 total thyroidectomy (in one or two stages, no residual disease present) within the
last 6 months

- Negative pregnancy test in women of child bearing potential

- Aged 16 or over

- WHO performance status 0 - 2, self-caring

- Histological confirmation of differentiated thyroid carcinoma:

- Papillary thyroid cancer

- Non aggressive histological features (small foci of aggressive histology
allowed)

- pT1b (1-2cm), intrathyroidal

- pT2 (2-4cm), intrathyroidal

- pT3, intrathyroidal only

- Multifocal microcarcinoma

- pN0

- pN1a

- pNX

- Follicular thyroid cancer/ Hürthle cell cancer (minimally invasive with capsular
invasion only)

- pT1b (1- 2cm), pT2 (2-4cm) intrathyroidal

Exclusion Criteria:

- Papillary and Follicular carcinoma which is unifocal and <1cm in size

- Encapsulated Follicular Variant of Papillary Thyroid Cancer (EFVPTC) that is:

- non-invasive

- angio invasive

- Anaplastic or medullary carcinoma

- R1 Thyroidectomy

- Patients with:

- pN1b

- M1

- Aggressive Papillary thyroid cancer with the following features:

- Angio invasive

- Widely invasive

- Poorly differentiated

- Anaplastic differentiation

- Tall cell

- Columnar cell

- Diffuse sclerosing variants

- Follicular thyroid cancer/ Hürthle cell cancer with the following features:

- Angio invasive

- Widely invasive

- Poorly differentiated

- Tumours greater than 4cm

- Incomplete resection/ lobectomy

- Macroscopic and microscopic tumour invasion of locoregional tissues or structures

- Pregnant women or women who are lactating

- Patients who have CT performed with iv contrast less than 3 months before ablation

- Previous treatment for thyroid cancer (except surgery)

- Previous malignancies with limited life expectancy or likely to interfere with the
patient's ability to be able to comply with treatment and/or follow-up at least for 5
years

- Dysphagia

- Oesophageal stricture

- Active gastritis

- Gastric erosions

- Peptic ulcer

- Suspected reduced gastrointestinal motility

- Severe co-morbid condition/s that would prevent ablation including:

- Unstable angina

- Recent myocardial infarction or cerebrovascular accident (CVA)

- Severe labile hypertension

- Any patient who cannot comply with radiation protection including:

- patients with learning difficulties

- patients with dementia

- patients with a tracheostomy that require nursing care

- patients requiring frequent nursing/ medical supervision