I'm currently enrolled in college, I need to complete 40 hours of volunteer service. I searched online, I found some volunteering opportunities, but they have nothing to do with radiology. I will probably be volunteering during the summer because I take 15 units per semester. I'm not sure if this helps, but I live in America.

If you are looking to volunteer and those are the lists your looking at then you might not find what you seek. Have you tried calling local radioligists and asking about summer interships? That is really what your looking for. Most are non paid positions. Im not sure so check with your school if that counts as volunteer.

Call your local hospitals and ask if they have job shadowing programs avaiable.

You will have to ask your advisor if job shadowing would meet the criteria for volunteering.