With using morphsnakes project, having perfect shaped contour

I wrote a program that calculates the area of the nodule with the help of morphsnakes project. But there is an issue with the borders around it. This borders are scattered, but I want them more organized, like a circle and ellipse. I try to change the parameters, like smoothing and threshold but still I can’t get the perfect shape. How can I achieve this?

Here is the image:

Ekran Resmi 2020-03-26 22.22.35