NMT 3210 Final Exam Questions And Answers
Graded A+ 2025/2026
What do we mean when we say that " radioactive decay is random?"
A) We cannot predict which element will be radioactive
B) We cannot predict the average decay rate of a radioactive material
C) We cannot predict when an individual atom with in a group of radioactive nuclei will
decay
D) We cannot predict when a radioactive material will reach background levels of
radiation - C) We cannot predict when an individual atom with in a group of radioactive
nuclei will decay
A vial of generator eluate contains 432 mCi immediately following elution. How many
mCi will remain 8 hrs later?
A) 172 mCi
B) 1,085 mCi
C) 257 mCi
D) 86 mCi - A) 172 mCi
All of. the following are International System (SI) units, EXCEPT:
A) gray (Gy)
B) sievert (Sv)
C) becquerel (Bq)
D) millicurie (mCi) - D) millicurie (mCi)
Which of the following measures of dose combines absorbed dose with the medical
effects of varying types of radiation?
A) tissues dose
B) equivalent dose
C) effective dose
D) absorbed dose - B) equivalent dose
A 10mCi dose of radionuclide would be equal to wha activity in becquerels?
A) 37 Bq
B) 3.7 Bq
C) 370 MBq
D) 37 MBq - C) 370 MBq
I-123 has a half-life of 13hrs. A sample of material had an activity of 5.6 mCi at noon
today. What was its activity at noon yesterday? (decay factor = 3.526)
,A) 15 mCi
B) 20 mCi
C) 10 mCi
D) 25 mCi - B) 20 mCi
A dose equivalent of 20 mSv is equal to
A) 1 rem
B) 2 rem
C) 1 mrem
D) 2 mrem - B) 2 rem
The half-life or a radioactive substance is the time it takes:
1. to decay to one -half its original activity
2. to deliver one-half of its radiation dose
3. for the number of radioactive nuclei to decrease by one-half
A) 1,2 & 3
B) 1 only
C) 1 & 2
D) 3 only - A) 1,2 & 3
Which of the following units describes the amount of radiation traveling through the air?
A) rad
B) curies
C) roentgen
D) rem - C) roentgen
A 20 mCi dose of TC-99m HDP results in a total body absorded dose of 0.25 rads. This
value is equivalent to:
A) .25 Gy
B) 2.50 mGy
C) 0.25 rem
D) 0.50 mSV - B) 2.50 mGy
P-32 has a half-life of 14.3 days. A sample has an original activity of 200 mCi. How
much will be left after 3 days?
A) 184 mCi
B) 173 mCi
C) 175 mCi
D) 179 mCi - B) 173 mCi
, If the radio activity of a TC-99m sample is 40 mCi at 8am, what will the activitity of the
sample be at 8pm?
A) 15 mCi
B) 10 mCi
C) 80 mCi
D) 20 mCi - B) 10 mCi
The decay constant is:
1. the fraction on nuclei which decay per unit time
2. the rate of radioactivity
3. the rate at which radiation dose if delivered
A) 2 & 3
B) 1 only
C) 1 & 3
D) 1 & 2 - B) 1 only
In which one of the folowing is the photoelectric effect most likely?
A) Nal crystal ( Z # 11 & 53)
B) The patient (low Z #s for C, H, O, N, Na and other elements)
C) Lead collimator ( Z # 82)
D) Air ( Z # 7 & 8) - C) Lead collimator ( Z # 82)
What structure is represented by "B" on the image?
A) glass envelope
B) anode
C) cathode
D) filament - B) anode
The type of X-ray interaction with matter in which all of the energy of the incident photon
is expended in dislodging a bound electron is called:
A) photoelectric effect
B) rayleigh scatter
C) pair production
D) compton effect - A) photoelectric effect
In the setting of X-ray production what are represented by sharp peaks when graphed?
A) auger x-rays
B) bremsstrahlung x-rays
C) rayleigh x-rays
D) characteristic x-rays - D) characteristic x-rays
Graded A+ 2025/2026
What do we mean when we say that " radioactive decay is random?"
A) We cannot predict which element will be radioactive
B) We cannot predict the average decay rate of a radioactive material
C) We cannot predict when an individual atom with in a group of radioactive nuclei will
decay
D) We cannot predict when a radioactive material will reach background levels of
radiation - C) We cannot predict when an individual atom with in a group of radioactive
nuclei will decay
A vial of generator eluate contains 432 mCi immediately following elution. How many
mCi will remain 8 hrs later?
A) 172 mCi
B) 1,085 mCi
C) 257 mCi
D) 86 mCi - A) 172 mCi
All of. the following are International System (SI) units, EXCEPT:
A) gray (Gy)
B) sievert (Sv)
C) becquerel (Bq)
D) millicurie (mCi) - D) millicurie (mCi)
Which of the following measures of dose combines absorbed dose with the medical
effects of varying types of radiation?
A) tissues dose
B) equivalent dose
C) effective dose
D) absorbed dose - B) equivalent dose
A 10mCi dose of radionuclide would be equal to wha activity in becquerels?
A) 37 Bq
B) 3.7 Bq
C) 370 MBq
D) 37 MBq - C) 370 MBq
I-123 has a half-life of 13hrs. A sample of material had an activity of 5.6 mCi at noon
today. What was its activity at noon yesterday? (decay factor = 3.526)
,A) 15 mCi
B) 20 mCi
C) 10 mCi
D) 25 mCi - B) 20 mCi
A dose equivalent of 20 mSv is equal to
A) 1 rem
B) 2 rem
C) 1 mrem
D) 2 mrem - B) 2 rem
The half-life or a radioactive substance is the time it takes:
1. to decay to one -half its original activity
2. to deliver one-half of its radiation dose
3. for the number of radioactive nuclei to decrease by one-half
A) 1,2 & 3
B) 1 only
C) 1 & 2
D) 3 only - A) 1,2 & 3
Which of the following units describes the amount of radiation traveling through the air?
A) rad
B) curies
C) roentgen
D) rem - C) roentgen
A 20 mCi dose of TC-99m HDP results in a total body absorded dose of 0.25 rads. This
value is equivalent to:
A) .25 Gy
B) 2.50 mGy
C) 0.25 rem
D) 0.50 mSV - B) 2.50 mGy
P-32 has a half-life of 14.3 days. A sample has an original activity of 200 mCi. How
much will be left after 3 days?
A) 184 mCi
B) 173 mCi
C) 175 mCi
D) 179 mCi - B) 173 mCi
, If the radio activity of a TC-99m sample is 40 mCi at 8am, what will the activitity of the
sample be at 8pm?
A) 15 mCi
B) 10 mCi
C) 80 mCi
D) 20 mCi - B) 10 mCi
The decay constant is:
1. the fraction on nuclei which decay per unit time
2. the rate of radioactivity
3. the rate at which radiation dose if delivered
A) 2 & 3
B) 1 only
C) 1 & 3
D) 1 & 2 - B) 1 only
In which one of the folowing is the photoelectric effect most likely?
A) Nal crystal ( Z # 11 & 53)
B) The patient (low Z #s for C, H, O, N, Na and other elements)
C) Lead collimator ( Z # 82)
D) Air ( Z # 7 & 8) - C) Lead collimator ( Z # 82)
What structure is represented by "B" on the image?
A) glass envelope
B) anode
C) cathode
D) filament - B) anode
The type of X-ray interaction with matter in which all of the energy of the incident photon
is expended in dislodging a bound electron is called:
A) photoelectric effect
B) rayleigh scatter
C) pair production
D) compton effect - A) photoelectric effect
In the setting of X-ray production what are represented by sharp peaks when graphed?
A) auger x-rays
B) bremsstrahlung x-rays
C) rayleigh x-rays
D) characteristic x-rays - D) characteristic x-rays
