Radiotherapy is an effective treatment for acromegaly but its effects are slow in onset. Although the greatest fall occurs in the first year after treatment, GH levels, if still raised, continue to fall for at least fifteen years. A great deal of skill and careful planning is necessary to ensure success without complications. Best results occur using a linear accelerator and a three field technique, which allows the largest dose of radiation to be delivered safely to the
tumour; this is not the case using the simpler two field, parallel opposed field technique.
Recurrence of tumour growth is very rare after radiotherapy ΓÇô less than one per cent.
