Photoshop Xray Effect Blog How Can You Create A Dotted Line Around A Curved/oddly Shaped Figure In Photoshop

How can you create a dotted line around a curved/oddly shaped figure in Photoshop - photoshop xray effect blog

I have a task of the university at which I identify anatomical structures on chest x-ray. I want to be able to explore around the different anatomy (eg, a rib, the heart shadow) on the radiograph, so that each structure is marked and easily distinguished.

Has anyone should consider proposals for tools or a combination of tools should you use? I am relatively new to HP, if you would also explain the steps, that's great.