Godfrey Hounsfield, 84, who developed the first practical CAT scan machine and shared a Nobel Prize in 1979 for inventing CAT scan technology, died Aug. 12 at a hospital in Kingston upon Thames, England. The cause of death was not reported.

His Nobel Prize was shared with Allan M. Cormack of Tufts University, who published the first theoretical papers on the system, but Mr. Hounsfield developed his machine without knowing of Cormack's work.

The Nobel committee described Mr. Hounsfield, who worked at EMI laboratories' medical research division, as "the central figure in computer-assisted tomography." The device uses X-rays to scan from different angles and a computer to assemble the images into a cross section.

In 1968, Mr. Hounsfield made a patent application that was granted in 1972, the year he tested the first device.

Developing the machine "involved many frustrations, occasional awareness of achievement when particular technical hurdles were overcome and some amusing incidents, not least the experiences of traveling across London by public transport carrying bullock's brains for use in evaluation of an experimental scanner rig in the laboratories," Mr. Hounsfield wrote in his autobiography for the Nobel committee.

Mr. Hounsfield never attended a university but had begun experimenting with electrical and mechanical devices as a boy growing up on a farm in Nottinghamshire.

"The period between my 11th and 18th years remains the most vivid in my memory because this was the time of my first attempts at experimentation, which might never have been made had I lived in a city," he recalled.

"I constructed electrical recording machines; I made hazardous investigations of the principles of flight, launching myself from the tops of haystacks with a homemade glider; I almost blew myself up during exciting experiments using water-filled tar barrels and acetylene to see how high they could be water jet propelled."

He served as a radar-mechanic instructor in World War II before being assigned to technical schools. After the war, he earned a diploma from the Faraday House Electrical Engineering College.