Contouring of a representative case. The clinical treatment volume (CTV) included the whole right breast, and was expanded 5 mm in the anterior–posterior and left–right directions to create a planning treatment volume (PTV) that excluded a 3 mm strip of skin and the lung tissue. The PTV ring was delineated around the PTV at 3 cm. Black mesh=tumor bed;white line=CTV;black line=PTV;white mesh=PTV ring.