Pneumothorax is a relatively common condition that is usually managed either conservatively, by chest tube drainage or, if a refractory air leak persists, then with cardiothoracic intervention. However, there is a small group of patients with a persistent air leak in whom surgical intervention is felt to be inappropriate. This study looks at a novel management strategy in a patient presenting with this scenario. A male with underlying bullous lung disease presented with a right pneumothorax. Complete re-expansion was not achieved, despite chest tube drainage and suction. Cardiothoracic intervention was felt to be inappropriate and the air leak persisted despite prolonged conservative management. Ventilation scintigraphy was therefore used to localise the air leak prior to targeted radiotherapy in an attempt to seal the leak via radiation-induced fibrosis. Three weeks after the first fraction of radiotherapy, the air leak ceased. In complex cases of pneumothorax with persistent air leak where cardiothoracic intervention is deemed inappropriate, identification of the air leak site and localised radiotherapy could be considered.