Elliptical selection precision

[khayne]

Hello,

I am currently doing a project where I have to make many small elliptical selections and add them to an ROI manager (to measure the area of each), because they are generally circular the easiest way is to use ctrl-alt-click and drag each.  My problem is that the selection is not precise enough for me, the circle formed snaps between diameters.  I need selection to be more precise (the circle drawn to be composed of more points/pixels), this is probably because the structures I'm measuring are quite small.  Is there a fix for my problem?  I am working on distributions of tube foot areas along the arm length of starfish for a Masters program.

Thanks,
Kurtis Hayne