Does ultrasound normally require injection of dye?

Typically not. In some echocardiogram studies some contrast or tiny air bubbles may be injected to look for holes across heart. But typically contrast only used in ct, MRI or angiogram.
No. The nice thing about ultrasound is that it does not involve any radiation exposure or the use of any dyes, intravenous or otherwise. Ultrasound relies upon the differences in the density of different structures, using sound waves to convert these differences into meaningful images.