Figure 3: Normalized, lateral beam profile, OARx, and longitudinal beam profile OARy of a TomoTherapy® HiArt® unit acquired at the depth of 10.0 cm in water at 85.0 cm SSD. (A) OARx with 2.5 cm and 5.0 cm field width; (B) OARy with 2.5 cm field width; and (C) OARy with 5.0 cm field width.