George Edward Pfahler (January 29, 1874 – January 29, 1957) was an American physician and one of the early influences on the specialty of radiology.

George E. Pfahler was born in Numidia, Pennsylvania on January 29, 1874.^[1] In 1898, he graduated from the Medico-Chirurgical College of Philadelphia. By the next year, he was an assistant chief resident at Philadelphia General Hospital. The hospital's board of managers procured an x-ray machine, then known as a "roentgen ray machine", and they appointed Pfahler to operate it. The young doctor had set out to become an internal medicine physician, and at first he doubted whether x-rays would have much value in the clinical care of patients. The rest of Pfahler's career was defined by his focus on direct patient care applications of X-rays.^[2]

After residency, Pfahler spent the early years of his medical career as a clinical professor at the Medico-Chirurgical College and as the director of the radiology departments at Philadelphia General Hospital and the Medico-Chirurgical Hospital. The Medico-Chirurgical College merged with the University of Pennsylvania in 1916, and Pfahler became a professor and vice dean of radiology at that institution. He worked at the medical school through 1946, and afterwards he was an emeritus professor.^[3] He made advances both in diagnostic radiology and in radiotherapy, taking special interest in radiation treatment for oral and breast cancers.^[2]

Pfahler was the 1910-11 president of the American Roentgen Ray Society, and he was the president of the American Radium Society in 1922.^[4][5] The next year, he became the first president of the American College of Radiology (ACR).^[6] He won the ACR Gold Medal, the organization's highest award, in 1952.^[7]

Pfahler married Frances Simpson on November 21, 1908. She died on March 15, 1910, and he remarred to Muriel Wilkes Bennett on July 10, 1918.^[8]

He died at Graduate Hospital in Philadelphia on January 29, 1957.^[9]

The Pfahler Hall of Science at Ursinus College is named in his honor.^[10]