Minnesota Medical Physics Technician
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
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1. What is the primary unit of absorbed radiation dose in the SI system?
A) Curie
B) Gray
C) Roentgen
D) Sievert
Answer: B) Gray
The Gray (Gy) is the SI unit of absorbed dose, representing energy
deposited per kilogram of tissue.
2. Which quantity accounts for biological effect of radiation?
A) Absorbed dose
B) Exposure
C) Equivalent dose
, D) Activity
Answer: C) Equivalent dose
Equivalent dose adjusts absorbed dose using radiation weighting
factors to reflect biological impact.
3. What is the function of a collimator in diagnostic imaging?
A) Increase scatter radiation
B) Limit X-ray beam size
C) Measure dose directly
D) Convert X-rays to light
Answer: B) Limit X-ray beam size
Collimators restrict beam size to reduce patient dose and improve
image quality.
4. Which detector is most commonly used in modern CT scanners?
A) Gas ionization chamber
B) Scintillation detector
C) Thermoluminescent dosimeter
D) Geiger-Müller tube
Answer: B) Scintillation detector
Scintillation detectors convert X-rays into visible light for digital
detection.
5. What is the half-life of a radionuclide?
A) Time to double activity
B) Time for half atoms to decay
, C) Time for full decay
D) Time for emission peak
Answer: B) Time for half atoms to decay
Half-life is the time required for half of radioactive atoms to undergo
decay.
6. Which radiation has the highest penetrating power?
A) Alpha particles
B) Beta particles
C) Gamma rays
D) Neutrons only
Answer: C) Gamma rays
Gamma rays are highly penetrating electromagnetic radiation.
7. What does ALARA stand for?
A) Always Limit Activity Radiation Amount
B) As Low As Reasonably Achievable
C) Average Level of Radiation Absorption
D) Active Linear Atomic Radiation Analysis
Answer: B) As Low As Reasonably Achievable
ALARA is a safety principle to minimize radiation exposure.
8. Which device measures cumulative radiation exposure over time?
A) Geiger counter
B) Dosimeter
C) Spectrometer
, D) Photometer
Answer: B) Dosimeter
Dosimeters record cumulative radiation dose received by a person.
9. What is the main purpose of lead shielding in radiology?
A) Increase image contrast
B) Absorb scattered radiation
C) Enhance photon energy
D) Improve detector sensitivity
Answer: B) Absorb scattered radiation
Lead shielding reduces exposure by absorbing stray radiation.
10. Which type of radiation is most dangerous internally if ingested?
A) Alpha
B) Beta
C) Gamma
D) X-ray
Answer: A) Alpha
Alpha particles cause severe damage when emitted inside the body
due to high ionization.
11. What is attenuation in radiation physics?
A) Increase in energy
B) Reduction in intensity
C) Conversion to heat
D) Production of photons
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary unit of absorbed radiation dose in the SI system?
A) Curie
B) Gray
C) Roentgen
D) Sievert
Answer: B) Gray
The Gray (Gy) is the SI unit of absorbed dose, representing energy
deposited per kilogram of tissue.
2. Which quantity accounts for biological effect of radiation?
A) Absorbed dose
B) Exposure
C) Equivalent dose
, D) Activity
Answer: C) Equivalent dose
Equivalent dose adjusts absorbed dose using radiation weighting
factors to reflect biological impact.
3. What is the function of a collimator in diagnostic imaging?
A) Increase scatter radiation
B) Limit X-ray beam size
C) Measure dose directly
D) Convert X-rays to light
Answer: B) Limit X-ray beam size
Collimators restrict beam size to reduce patient dose and improve
image quality.
4. Which detector is most commonly used in modern CT scanners?
A) Gas ionization chamber
B) Scintillation detector
C) Thermoluminescent dosimeter
D) Geiger-Müller tube
Answer: B) Scintillation detector
Scintillation detectors convert X-rays into visible light for digital
detection.
5. What is the half-life of a radionuclide?
A) Time to double activity
B) Time for half atoms to decay
, C) Time for full decay
D) Time for emission peak
Answer: B) Time for half atoms to decay
Half-life is the time required for half of radioactive atoms to undergo
decay.
6. Which radiation has the highest penetrating power?
A) Alpha particles
B) Beta particles
C) Gamma rays
D) Neutrons only
Answer: C) Gamma rays
Gamma rays are highly penetrating electromagnetic radiation.
7. What does ALARA stand for?
A) Always Limit Activity Radiation Amount
B) As Low As Reasonably Achievable
C) Average Level of Radiation Absorption
D) Active Linear Atomic Radiation Analysis
Answer: B) As Low As Reasonably Achievable
ALARA is a safety principle to minimize radiation exposure.
8. Which device measures cumulative radiation exposure over time?
A) Geiger counter
B) Dosimeter
C) Spectrometer
, D) Photometer
Answer: B) Dosimeter
Dosimeters record cumulative radiation dose received by a person.
9. What is the main purpose of lead shielding in radiology?
A) Increase image contrast
B) Absorb scattered radiation
C) Enhance photon energy
D) Improve detector sensitivity
Answer: B) Absorb scattered radiation
Lead shielding reduces exposure by absorbing stray radiation.
10. Which type of radiation is most dangerous internally if ingested?
A) Alpha
B) Beta
C) Gamma
D) X-ray
Answer: A) Alpha
Alpha particles cause severe damage when emitted inside the body
due to high ionization.
11. What is attenuation in radiation physics?
A) Increase in energy
B) Reduction in intensity
C) Conversion to heat
D) Production of photons
