If you have trouble accessing any particular NEJM articles, Drexel Libraries has access.
For policy guidance, in addition to knowing the regulatory landscape you also want to know about industry ethics and best practices. For this, industry publications, non-profits focused on the particular issue, and professional associations will be your best sources.
McDermott (a law firm) has created the AI in Healthcare Resource Center which has a well-organizedguide to all agency and legislative actions in the United States involving AI and health care. Manatt, Phelps, and Phelps has a newsletter called Manatt Health that serves a similar purpose.