NHR Rad520 Radioactivity

Question 1

What are A, B, C, and D and what Model is this?

Answer 1

Bohr’s Model
A = Nucleus
B = 1st/k shell (2 electrons)
C = 2nd/L shell (8 electrons)
D = 3rd/M shell (18 electrons)

Question 2

Bohr’s model _____ calculate the max number of electrons in each respective shell.

Answer 2

2n²

Question 3

Identify A, B, and C:

Answer 3

A = atomic number or proton number (Z)
B = Elemental Symbol
C = Atomic Mass in Amu

Question 4

Find the energy converted using E = mC^{2 of the following:
0.0989 amu}

Answer 4

Question 5

Nuclear Binding Energy: 1 eV = 1.602 x 10^-19 J

Answer 5

Question 6

Complete the table:

Answer 6

Question 7

What is the equation for radioactive decay?

Answer 7

N_{t = number of atoms after time
No = original number of atoms
t = time elapsed
λ = decay constant (number of atoms decaying per unit of time)}

Question 8

What is the decay constant (λ)?

Answer 8

Question 9

How do you calculate activity (decay, disintegrations per unit of time)?

Answer 9

A_{t = number of atoms after time
Ao = original number of atoms
t = time elapsed
λ = decay constant (number of atoms decaying per unit of time)}

Question 10

True or False: 1 Bq = 2.7 x 10^-11 Ci

Answer 10

True

Question 11

True or False: 1 Ci = 3.7 x 10^10 Bq

Answer 11

True

Question 12

How do you calculate mean or average life (τ)?

Answer 12

Question 13

What is the average life for Radium^226?

Answer 13

Question 14

What is this decay method?

Answer 14

Alpha α

Question 15

What is this decay method?

Answer 15

Alpha α

Question 16

What is this decay method?

Answer 16

β; β negative and β positive

Question 17

What is this decay method?

Answer 17

electron capture

Question 18

A Flattening Filter _____ the average energy and _____ the total radiation quantity?

A. Decreases, Increases
B. Decreases, decreases
C. Increases, decreases
D. Increases, Increases

Answer 18

C. Increases, decreases

From Quiz 1

Question 19

Which of the following decay modes is most prominent in the heavier elements in the periodic table?

A. Electron Capture
B. Alpha
C. Beta negative
D. Beta positive

Answer 19

B. Alpha

From Quiz 1

Question 20

An increase in kVp has a _____ effect on electron output, while mAs has a _____ effect.

A. Direct, direct
B. squared, squared
C. Direct, squared
D. Squared, direct

Answer 20

D. Squared, direct

From Quiz 1

Question 21

Which of the following photon interactions results in a scattered photon with less energy and an ejected orbital electron?

A. Coherent scatter
B. Compton scatter
C. Photoelectric effect
D. Pair Production

Answer 21

B. Compton scatter

From Quiz 1

Question 22

Which of the following radiation measurement devices utilizes a p-type and n-type junction?

A. TLD
B. Silicon diode
C. Film
D. Farmer chamber

Answer 22

B. Silicon diode

From Quiz 1

Question 23

Which of the following organizations would be utilized to calibrate an ion chamber for a clinical site?

A. ADCL
B. PSDL
C. IAEA
D. AAPm

Answer 23

A. ADCL

From Quiz 1

Question 24

How would an increase in SSD affect the geometric penumbra width?

A. No effect
B. Increase
C. Depends on isotope used
D. Decrease

Answer 24

B. Increase

From Quiz 1

Question 25

Compared to photon mode, electron mode uses a _____ machine current and the _____ on the carousel.

A. Higher, scattering foil
B. Lower, scattering foil
C. Lower, flattening filter
D. Higher, flattening filter

Answer 25

B. Lower, scattering foil

From Quiz 1

Question 26

How long would it take a 15 Ci iridium^192 source to decay to 11 Ci? What’s the base equation?

Answer 26

From Quiz 1

Question 27

What is the μ for a beam that is attenuated 95% by a 5 mm piece of lead? What is the base problem?

Answer 27

From Quiz 1

Question 28

How many HVLs are in the beam path when there is 300 cGy/min without shielding & 42 cGy/min with shielding?

Answer 28

Find what is transmitted then find the HVLs.
(I_{x/(Io) = (42 cGy/min)/(300 cGy/min) => 0.14 transmitted}

0.5^{n = 0.14 => ln 0.5n = ln 0.14 => n = (ln 0.14)/(ln 0.5) => n = 2.837}

Question 29

What is the intensity of a beam passing through a filter that has a linear attenuation coefficient of 0.019 cm^{-1 and a thickness of 1.5 cm? The original intensity was 200 cGy/min.}

Answer 29

Equation: Ix = Io e^-μx

Ix = ???
Io = 200 cGy/min
μ = 0.019 cm^-1
x = 1.5 cm

Ix = (200 cGy/min) e^-0.0285

Ix = (200 cGy/min) (0.972)

I_{x = 194.4 cGy/min}