Using pathgeometry to make button.

I'm trying to use pathgeometry as button style but I can't specify
imagebrush as my background. I can change opacity and borderbrush but
background can't be changed. Can I change background when use
pathgeometry as button style?

You can refrence below code:
<Path Stroke="Black" StrokeThickness="1" Fill="#CCCCFF">
<Path.Data>

<!-- Creates a composite shape from three geometries. -->
<GeometryGroup FillRule="EvenOdd">
<EllipseGeometry Center="40,70" RadiusX="30" RadiusY="30" />

<RectangleGeometry Rect="30,55 100 30" />
</GeometryGroup>
</Path.Data>
</Path>