If you have SolidWorks Premium, Scanto3D may be able to read it. I don't have Scanto3D with my license, so I can't tell you for sure. You could probably convert the PLY to a point cloud format that Scanto3D could read if for some reason it won't open a PLY.
If you don't have SolidWorks Premium, you would have to convert it to a mesh format like STL or VRML, and its usefulness would be limited. A scan typically has hundreds of thousand, or millions of points. The only way to import that is using the Graphics Body option, and then it is only a visual reference, for tracing. You cannot snap to it or generate sections from it.
If its possible to decimate it down without loosing the detail you need, you could import approx 15,000 triangles as a Solid Body, or slightly more as a Surface Body, which you could then use with the modeling or sketching tools.
Can you comment on how you are using the scan ... that might help with additional suggestions.