It was well after midnight when Dr. Salvatore J. A. Sclafani finally hit the “send” button.

Soon, colleagues would awake to his e-mail, expressing his anguish and shame over the discovery that the tiniest, most vulnerable of all patients  premature babies  had been over-radiated in the department he ran at State University of New York Downstate Medical Center in Brooklyn.

A day earlier, Dr. Sclafani noticed that a newborn had been irradiated from head to toe  with no gonadal shielding  even though only a simple chest X-ray had been ordered.

“I was mortified,” he wrote on July 27, 2007. Worse, technologists had given the same baby about 10 of these whole-body X-rays. “Full, unabashed, total irradiation of a neonate,” Dr. Sclafani said, adding, “This poor, defenseless baby.”

And the problems did not end there. Dr. John Amodio, the hospital’s new pediatric radiologist, found that full-body X-rays of premature babies had occurred often, that radiation levels on powerful CT scanners had been set too high for infants, and that babies had been poorly positioned, making it hard for doctors to interpret the images.