SOLUTIONS RATED A+
✔✔What is a valence number? - ✔✔The number of electrons in the last orbital shell
(cannot go beyond 8)
2n^2 (defines max # of e- in one shell)
-If valence is not used in a problem, use the formula (2n^2)
✔✔What are the electron binding energies of the Tungsten shells? - ✔✔K= 69.53
L= 12
M= 3
N=1
✔✔What is ionization? - ✔✔Removal of an electron from one of the orbital shells
The previously uncharged atom will now have an electrical potential (positively charged)
✔✔Excitation - ✔✔energy source does not contain enough kinetic energy to ionize the
atom rather it contains energy only to vibrate atom
✔✔Isotope - ✔✔Atom of an element with the same atomic number as the element but
with a different atomic mass (diff numbers of neutrons)
✔✔Produced in tube - ✔✔Brem and Characteristic
✔✔Produced in x-ray interacts with matter - ✔✔compton, photoelectric, etc.
✔✔Bremsstrahlung radiation - ✔✔(Breaking radiation)
Projectile (high speed) electron interacts with the electrostatic charge of the target
(tungsten) nucleus
"Drive by real close and turn around"
✔✔What are the three processes that projectile electrons undergo? - ✔✔Slows down
Changes direction
Loses some of its energy
-This process results in the emission of a brem xray photon
-Brem photon energy is equal to the amount of energy lost by the projectile energy
-The greater the direction change the greater energy loss and the brem xray photon will
posess more energy
✔✔What is Characteristic Radiation? - ✔✔(K-shell)
Projectile (high-speed) e- interacts with the tungsten target atom by ejecting an inner
shell electron and ionizing the atom
K-shell vacancy is filled by an outer shell electron
-The electron may be filled by a L, M, N, O, or P orbital shell of the
,-The process of filling the vacant K shell results in the emission of a characteristic x-ray
photon
-Energy of the x-ray photon is equal to the difference between the electron binding
energies of the orbital shell that contained the vacancy(k-shell) and the orbital shell that
filled the vacancy
✔✔When producing K characterstic, you must have a potential difference/voltage of
what? - ✔✔70;
Anything below 70 is all bremsstrahlung
✔✔What does the characteristic emission graph look like? - ✔✔Like a bar graph;
X-axis= x-ray energy
Y-axis= quantity of radiation
Factors that influences energy levels of characteristic radiation production
✔✔Factors that influences energy levels of characteristic radiation production - ✔✔a
change in the target material
✔✔What does the bremsstrahlung emission graph look like? - ✔✔Bell curve;
Peak of curve= energy level at which most x-rays are produced (greatest number
produced about 30% of peak energy)
✔✔Factors that influences the bremstrahlung emission graph - ✔✔mAs= increasing
mAs causes amplitude (rise) of the curve
kVp= increasing kVp causes the amplitude to rise and shift to the right
distance= increasing distance from radiation source will cause amplitude of curve to fall
filtration= increasing filtration will cause amplitude to fall and shift the curve to the right
✔✔X-ray is what type of energy on electromagnetic spectrum? - ✔✔electromagnetic
energy
✔✔Photon - ✔✔(Quantum)
Smallest bit of electromagnetic energy
✔✔Wave-particle duality - ✔✔some electromagnetic energy forms may take on the
characteristics of particles
✔✔Frequency - ✔✔the rate of rise and fall (oscillation) of the electromagnetic photon
and is measured in the unit Hertz (Hz)
✔✔Wavelength - ✔✔is the distance between the two successive peaks of an
electromagnetic photon
✔✔What is the relationship between frequency and wavelength? - ✔✔Inversely related;
X-radiation has very high frequencies and very short wavelengths
, ✔✔(T/F) As the frequency of electromagnetic radiation (x-ray photon) increases, the
wavelength will decrease - ✔✔True
✔✔Energy of electromagnetic radiation is directly proportional to frequency and
inversely proportional to wavelength - ✔✔True. E=f/wavelength
✔✔What is the speed of x-rays? - ✔✔186,000 miles/second or 3 x 10^8 meters/sec
Travel at the speed of light or not at all
✔✔What are the four properties of photons? - ✔✔Frequency
Wavelength
Velocity
Amplitude
✔✔Is there a difference in velocity for photons? - ✔✔No. Velocity is constant.
✔✔Longer wavelength - ✔✔lower frequency (60 kV)
✔✔Shorter wavelength - ✔✔higher frequency (90 kV)
✔✔What is the difference between x-ray and gamma rays? - ✔✔Source of origin
✔✔Relationship between wavelength, frequency, and energy -
✔✔wavlength/frequency= inverse
wavelength/energy= inverse
frequency/energy= direct
✔✔Quality - ✔✔(kVp; energy and penetrability)
Influenced by:
increase kVp results in an increase in X-ray quality and an increase in penetrability
an increase in filtration results in an increase x-ray quality, although the peak energy
has not changed
✔✔Quantity - ✔✔(mAs; rate, intensity, pt dose)
Influenced by:
X-ray quantity directly proportional to mAs
I1/I2 = mAs1/mAs2 (no squaring)
Ex. 70 kVp, 10 mAs, pt dose of 18 C/kg; New exposure 25 mAs, what is new intensity?
18/x = 10/25 = x= 450/50 = 45 C/kg
✔✔Filtration - ✔✔(increases quality; decreases quantity)
Measured in half-value layer= thickness of an absorbing material required to reduce the
x-ray intensity by one-half of its original value