CH. 5, 8, 13 RADT 1065 EXAM
QUESTIONS AND ANSWERS
When x-rays are produced, they are emitted ____________________, that is, with
equal intensity in all directions. - Answer- isotropically
X-rays that escape through the protective housing are ____________________;
they contribute nothing in the way of diagnostic information and result in
unnecessary exposure of the patient and the radiologic technologist. - Answer-
leakage radiation
Properly designed protective housing reduces the level of leakage radiation to less
than ____________________, when operated at maximum conditions. - Answer-
100mR/hr. at 1 meter
Dielectric oil surrounding the x-ray tube is useful for what purpose? - Answer- fills
space between the envelope and the tube housing
insulates the high-voltage components from the tube housing
Glass-type x-ray tubes are made up of what material (what type of glass)? - Answer-
Pyrex glass
When comparing metal and glass-type enclosure x-ray tubes, which of the two
generally has a longer life and is less likely to fail? - Answer- Metal envelope
because it eliminates problem of Tungsten vaporization
The process of boiling off of electrons at the filament is known as
____________________. - Answer- space charge effect
thermionic emission
Filaments are usually made of ____________________. - Answer- thoriated
tungsten
____________________ with deposition on the inside of the glass enclosure is the
most common cause of tube failure. - Answer- Tungsten Vaporization
The focusing cup has what type of charge applied to it? - Answer- low negative
* The tube phenomenon that restricts the further emission of electrons from the
filament is called ____________________. This serves to limit the mA capacity to
1,000 - 1,200 mA. (cant be higher) - Answer- space charge effect
QUESTIONS AND ANSWERS
When x-rays are produced, they are emitted ____________________, that is, with
equal intensity in all directions. - Answer- isotropically
X-rays that escape through the protective housing are ____________________;
they contribute nothing in the way of diagnostic information and result in
unnecessary exposure of the patient and the radiologic technologist. - Answer-
leakage radiation
Properly designed protective housing reduces the level of leakage radiation to less
than ____________________, when operated at maximum conditions. - Answer-
100mR/hr. at 1 meter
Dielectric oil surrounding the x-ray tube is useful for what purpose? - Answer- fills
space between the envelope and the tube housing
insulates the high-voltage components from the tube housing
Glass-type x-ray tubes are made up of what material (what type of glass)? - Answer-
Pyrex glass
When comparing metal and glass-type enclosure x-ray tubes, which of the two
generally has a longer life and is less likely to fail? - Answer- Metal envelope
because it eliminates problem of Tungsten vaporization
The process of boiling off of electrons at the filament is known as
____________________. - Answer- space charge effect
thermionic emission
Filaments are usually made of ____________________. - Answer- thoriated
tungsten
____________________ with deposition on the inside of the glass enclosure is the
most common cause of tube failure. - Answer- Tungsten Vaporization
The focusing cup has what type of charge applied to it? - Answer- low negative
* The tube phenomenon that restricts the further emission of electrons from the
filament is called ____________________. This serves to limit the mA capacity to
1,000 - 1,200 mA. (cant be higher) - Answer- space charge effect
