If \( S \) and \( S' \) are the foci of the ellipse \( \frac{x^{2}}{18} + \frac{y^{2}}{9} = 1 \) and \( P \) be a point on the ellipse, then \( \min(SP \cdot S'P) + \max(SP \cdot S'P) \) is equal to:
\( 3(6 + \sqrt{2}) \)
\( 27 \)
\( 9 \)
\( 3(1 + \sqrt{2}) \)