How can I defeat Medusa?

I just had a nice encounter with Medusa. Unfortunately I didn't survive it.

This fight seems quite a bit nastier than the other legendary creatures I already killed. The beam she casts seems quite deadly, and while I didn't test it I assume it'll turn me to stone if I stay out of cover long enough. But the most dangerous part was the other attack, three circles on the ground that don't need line of sight. They did hit me rather well while I was hiding behind a pillar, and I didn't manage to avoid them often enough.

The thing that killed me in the end was that I ran out of adrenaline, and couldn't refill it to heal.

How can I defeat Medusa? Any particular tricks, or any tips on how to avoid her attacks?

You already get the right tactics: 1. hide behind the pillars to avoid the beam, 2. avoid the circles (she casts it as soon she raises her arm) 3. use your bow and hunter skills to get her HP as low as you can while hiding behind the pillars.

Also bow attacks can refill your adrenaline if you manage to give her (or her summoned creatures) head-shots. And use fire with fast weapons on medusa as soon her summoned creatures are vanquished.