Mihran Krikor Kassabian (August 25, 1870 – July 14, 1910)[nb 1] was an Armenian-American physician, one of the early investigators into the medical uses of X-rays, and a faculty member at the Medico-Chirurgical College of Philadelphia.

Born in Kayseri, Kassabian studied in London and Philadelphia before serving in the United States Army Hospital Corps during the Spanish–American War.

He represented the American Medical Association at international conventions, and in 1907 he wrote an influential textbook on electrotherapeutics and radiology.

Because he worked with X-rays every day in an era before lead shielding had been widely adopted, he sustained radiation burns to his hands, had two fingers amputated, and developed skin cancer within a few years of becoming a physician.

[2] Kayseri and other cities in present-day Turkey lie on various fault lines, producing an unpredictable pattern of seismic activity.

[5] Kassabian grew up in poverty and, as biographer Percy Brown put it, "with almost constant danger of earthquake or massacre" during his early years.

It was during the war that Kassabian first gained experience with the use of X-rays, which had been discovered only a short time earlier by German engineer and physicist Wilhelm Röntgen.

[9] Photographers, engineers, and X-ray technicians had all begun to work with such machines, but Kassabian and his colleagues in the US and Europe lobbied to keep the devices under the direct control of physicians.

However, due to pressure from physicians like Kassabian, such studios closed within a few years, and the use of X-rays was limited to medical facilities.

[9] However, shortly before Kassabian's arrival, Pfahler's laboratory had made the second-ever X-ray diagnosis of a brain tumor.

Due to the difficulty of controlling the contrast agent and the problems caused by the beating of the heart, his procedure did not become a standard medical practice.

[15] A portion of the book covered forensic uses of radiology, and that helped to establish Kassabian as an expert witness in court.

[6] He served as chair of the medicolegal committee of the American Roentgen Ray Society (ARRS), and he believed that X-rays could reduce frivolous litigation by providing judges and juries with visual depictions of the medical information pertinent to court cases.

[17] Much of the early work of radiologists involved fluoroscopy, which allowed a body part to be examined through continuous X-ray exposure.

His 1907 textbook included several pages of content on X-ray injuries, summarizing 12 lawsuits brought by radiation-injured patients against their doctors.

Kassabian and most other radiologists did not practice shielding; they felt that lead aprons were impractical, unnecessary, or potentially distressing to patients.