Liability depends on several factors. Doctors, nurses, pharmacology technicians, radiation technicians, or anesthesiologists can all be held accountable. However, you can hold other parties, such as the hospital or the employer of anyone who was a party to malpractice, partially liable.
Hospitals can be held accountable for poor training or poor hiring practices. They may also be liable if they have failed to take disciplinary action against someone who has had complaints lodged against them that may have identified early issues.