1 m/c transmission clinical intstrument
date: label: date made
content: about 1958
name: label: Associated Name
content: University of Minnesota
label: maker
content: Wild, John J.
notes: label: Description
content: In the late 1950s John Wild worked with other scientists to develop an ultrasound scanner that could image the thorax. To do this, continuous wave ultrasonic energy had to be directed through the thorax, including the heart and lungs. This instrument was used successfully and demonstrated that imaging the complete thorax could be accomplished without apparent harm.
label: Description
content: This instrument used transducers at the lower 1 megacycle instead of the higher, 15 megacycles that Wild used in previous instruments. Because the sound waves produced are continuous, there is no break for the crystal sending the pulses to also receive them. This is different from Wild's "pulse-echo" instruments in which a sound head produces the sound waves in a pulse, in between which the echo is received. Because the sound wave has to travel in one direction then travel that same distance back as an echo, the energy is ultimately much lower and the instrument cannot be used to image deeper parts of the body. In the thorax imaging instrument, the goal was to send sound waves completely "through" the body. For this reason, the instrument has two transducers, placed across from each other on either side of the thorax. Instead of one transducer sending a sound wave and pausing to receive an echo, one transducer acts as the "sending" transducer and the other is the "receiving" transducer. The transmitting transducer sends a continuous ultrasonic pulse at a strong enough frequency (1mc) to go through the body's tissue and be received by the receiving transducer across from it, but not strong enough to harm the body. The instrument is used while the patient is standing or laying on their side. The instrument is structured in a triangle frame with two suspended arms on either side. Each arm holds a transducer meant to come in contact with the patient's skin to produce and record ultrasound pulses.
label: Description
content: In clinical tests, three things were recorded: the patient's pulse, ultrasound echoes, and electrocardiographic data. Testing on a human patient showed that ultrasound could be driven completely through the thorax and, importantly, that heart motion modified the transmitted ultrasound. This was shown by ultrasonic "peaks" and "valleys" that occurred in regular relationship with the data from the electrocardiograph. These findings were similar to other doctors who found ultrasound useful in cardiology by using principles of the Doppler Effect.
label: Description
content: The basic ultrasound machine is made up of a transducer, amplifier, and display unit. The transducer is placed close to the tissue being imaged and electrical signals cause the transducer inside to produce mechanical sound waves. The transducer sends sound waves into the tissue which then bounce back as echoes. Each echo is received as sound waves and translated back to an electrical signal by the transducer. The electric signal is amplified many times which allows it to be "read" by the display unit, creating the image of dots on the screen. Each dot corresponds to the time (depth,) amplitude (strength,) and location of the obstruction that sent that particular echo back. John Wild and John Reid constructed a multi-purpose clinical display unit in 1951 to be used with multiple short range and hand-held instruments. Once they proved that tissue abnormalities were indeed distinguishable through ultrasound imaging, Wild continued to develop more advanced methods to image parts of the body for diagnostic purposes, which led him to create this thorax scanner.
label: Location
content: Currently not on view
place: label: place made
content: United States: Minnesota, Minneapolis
topic: label: Subject
content: Ultrasound
label: Subject
content: Radar
label: Subject
content: Cancer
label: Subject
content: Imaging
label: Subject
content: Diagnostic Equipment
label: Subject
content: Medicine
setName: label: See more items in
content: Medicine and Science: Medicine
creditLine: label: Credit Line
content: Gift of Ellen L. C. Wild and Valerie C. Wild
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 2015.0300.11
label: accession number
content: 2015.0300
label: catalog number
content: 2015.0300.11
objectType: label: Object Name
content: ultrasound thorasic scanner
physicalDescription: label: Physical Description
content: metal (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: rubber (wire material)
label: Physical Description
content: plastic (overall material)
label: Physical Description
content: adhesive tape (cord material)
label: Physical Description
content: sauter (overall material)
label: Measurements
content: overall: 60 cm x 47 cm x 6.5 cm; 23 5/8 in x 18 1/2 in x 2 9/16 in
label: Measurements
content: cord: 93 cm; 36 5/8 in