XNA Sprite Scaling: looking for uniform expansion from the center of the sprite

When I scale my sprite, it's stretches out to the lower right, when the desired effect is for it to stay put and 'grow' in concentric circles.

I fiddled around with the origin, but it seems to only affect rotation. I've also thought about using the bounding rectangle to scale it, but I'm looking for a best practice so as not to get into a bad habit right out of the gate.

Here's the code where I make the call. The only arg that changes is Scale:

SpriteBatch.Draw(Texture,            // Texture
                          Position,           // Position
          开发者_C百科                null,               // Source Rectangle
                          Color,              // Color
                          0f,                 // Rotation
                          Vector2.Zero,       // Origin
                          Scale,              // Current Scale
                          SpriteEffects.None, // Mirroring options
                          Depth);             // z-depth

And here's a screenshot of the orange rings expanding without staying 'stacked':

Thanks for your time.

Here's a detail of the fixed version if it helps anyone:

The sprite origin passed to SpriteBatch.Draw is specified in sprite coordinates (pixels) and is used as the origin for scaling, as well rotation and position.

Scale is specified as a multiplier (so Vector2.One is at "normal" size).