Photographing the Speed of the Human Blood-Stream

Abstract

HomeRadiologyVol. 10, No. 3 PreviousNext EditorialPhotographing the Speed of the Human Blood-StreamPublished Online:Mar 1 1928https://doi.org/10.1148/10.3.260bMoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In AbstractBy the use of a device which records the presence of a ray given off by radio-active material, the motion of the human blood-stream is being measured and analyzed by Dr. Herman Blumgart at the Thorndike Memorial Hospital in Boston, Mass. This device, known as the Geiger Electric Counter, is so sensitive that it will detect the presence of emanations so weak that chemical analysis cannot bring them to light.Radio-active preparations are injected in small quantities into the blood-stream of the patient, and with the Geiger apparatus are detected as they reach different parts of the circulatory system. A strip of motion picture film used in connection with a sensitive reflecting galvanometer, or a siphon recorder similar to those used in trans-Atlantic telegraphy, serves to make records of the active material as it passes the point at which the Geiger detector is held.The original apparatus was devised by Hans Geiger, a German scientist, in 1906, for the purpose of making quantitative studies of the emanations of radium. Recently, Dr. C. W. Hewlett, of the General Electric Research Laboratories, improved the device, so that its indications are easily controlled and reliable.The apparatus consists of a small brass chamber within which a very sharp platinum needle is held by an insulating collar. The chamber is closed at one end with a hard rubber plug and at the other by a thin aluminum plate, and a direct-current potential of 1,500 to 2,000 volts is maintained between the needle and the chamber wall. When a radio-active ray enters through the aluminum window, ionization of the enclosed air takes place, and in the intense electrostatic field at the point of the needle a current rush is set up that is many thousand times as large as that represented by the original ray. If some detecting device such as high impedance radio head 'phones, a string galvanometer, or a siphon recorder is connected in the high-potential circuit with the needle, the impulses set up by the ray can be read or recorded. By suitable amplification, the impulses can be built up to such an extent that relays may be operated, or a loud speaker made to register the sound.The apparatus developed by Dr. Hewlett is contained in a box about three feet long and a foot square, and consists of a kenetron rectifier and filter equipment for supplying the high potential, and a special amplifying set. The Geiger chamber is portable, being encased in hard rubber and connected to the amplifier by a flexible cable. Chamber, cable, and apparatus box are all carefully shielded to protect them from stray electrostatic disturbances in the room.As used by Dr. Blumgart, one or several chambers are placed on various parts of the patient's body, radio-active material is injected into the blood stream, and the time of arrival is recorded on the tape or film. Since the active rays will penetrate the body without difficulty, readings may be taken at any desired point without making an incision.Article HistoryPublished in print: Mar 1928 FiguresReferencesRelatedDetailsRecommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 10, No. 3 Metrics Altmetric Score PDF download