Lesson 9&10 Flashcards
What are the xray generating apparatus?
°1. ELECTRICITY
°2. ELECTRICAL CURRENT
°3. ELECTRICAL CIRCUIT
energy to make xrays
associated with presence and flow of electric charge or electrons around a circuit
ELECTRICITY
flow of electrical energy / electrons through a circuit measured in amperes
ELECTRIC CURRENT
path of electrical current
ELECTRICAL CIRCUIT
What are the flow of current in 2 phases?
1 positive phase
1 negative phase
first half-cycle
(positive phase)
•second half-cycle
(negative phase
First half cycle current
flows; ______ produced
x-rays
second
half-cycle> no _________; no x-
ray production.
current flow,
therefore, in xray production
There is a change in polarity of the anode
and cathode that occurs
6ox /sec
Reverse voltage
•60-cycle AC
l
• 6o pulses of x-rays emitted every second
l
• Duration: ______ sec
1/120
**rays are produced in the form of______
impulses
•the tube does its own rectification
SELF-RECTIFICATION
type of power that limits xray production to half of the AC cycle
halfwave rectification
2 electrical circuits for ray production:
- Filament circuit
II. Anode-cathode circuit
- on-off switch
- mA control
- step-down transformer
Filament or low voltage circuit.
Anode-cathode or high voltage circuit
- kVp selector
- timer
- activating button
- x-ray emission light /
sound OR indicator button - step-up transformer
> length of time to produce xrays
controlled by the timer
Exposure time
> Expressed as:
fraction of a second
whole numbers of seconds
impulses per exposure
Exposure time
Formula to determine exposure time in seconds:
no. of impulses
——————— = exposure time in seconds
60
Formula to determine exposure time in impulses:
exposure time in sec X 6o = exposure time in impulses
2 terms to regarding number of electrons and electrical force:
• 1. amperage
- Voltage
measure of the amount of electrical current flowing through a circuit
amperage
- 8 to 15 mA
- adjusted with the mA selector
amperage
measurement of electrical force needed to move electrons from a (-) to(4)
electrode
Voltage
65 to 95 kV or 65,000 to 95,000volts
Voltage
kVp = highest voltage to which rays are
produced
Voltage
True or false
mAand voltage affects quality of the ray beam
True
HEAT - 99%
X-RAYS- 1%
Tube interactions
True or false
X-ray beam is a solid beam
False
(X-ray beam is NOT a solid beam)
True or false
Electrical energy is converted to x-ray energy
and heat
True
True or false
Millions of high-speed electrons from the cathode interact with uncountable numbers of tungsten atoms at the target. The sudden stopping of the electron motion causes kinetic energy of the electrons to EM energy
True
True or false
The millions of x-rays produced are of same wavelengths and energies
False
(The millions of x-rays produced are of different wavelengths and energies)