How to draw gradient transparent circle in vb.net ?

Dim g As Graphics = e.Graphics
       Dim width As Integer = Me.ClientRectangle.Width / 2
       Dim height As Integer = Me.ClientRectangle.Height / 2

       Dim b As PathGradientBrush
       Dim x As Integer = 0
       Dim y As Integer = 0
       Dim circle As GraphicsPath = New GraphicsPath()
       circle.AddEllipse(0, 0, width, height)
       b = New PathGradientBrush(circle)
       b.WrapMode = WrapMode.Tile

       b.SurroundColors = New Color() {Color.Yellow}
       b.CenterColor = Color.Red
       g.FillRectangle(b, x, y, width, height)