The study, which was published online Monday in The Journal of Clinical Oncology, was conducted by Dr. Reshma Jagsi, a radiation oncologist and ethicist at the University of Michigan, who had grown concerned about the practice and wanted to know more.

Dr. Jagsi said she had sat in on workshops, seminars, training sessions and department meetings that discussed how to identify good prospects for gifts, how to direct grateful patients to the development office, and how to ask them directly if they wanted to donate.

She was uncomfortable with the idea, but she also knew some patients want to donate and are grateful for guidance on how to do it. And she knew medical centers needed money now more than ever. What was the ethical way for doctors to help, she wondered? Or should they stay out of the donation business completely?

She searched the medical literature for studies on the subject and found pretty much nothing, so she decided to conduct her own research.

The issue is “extraordinarily important,” said Arthur L. Caplan, head of the division of medical ethics at NYU Langone Medical Center, adding that he had never seen a paper that examined the issues as thoroughly as Dr. Jagsi’s. “Hopefully, this paper will start a long overdue discussion,” he said.