Radiography Exam Radiology Tech 2 — Questions and Answers
Question 1: Which unit is used to measure radiation absorbed dose in SI units?
- Roentgen
- Rad
- Gray (Correct answer)
- Sievert
Correct answer: Gray
The Gray (Gy) is the SI unit of absorbed dose, equal to 1 joule of energy deposited per kilogram of tissue.
Question 2: What is the primary purpose of a grid in radiographic imaging?
- Increase patient dose
- Reduce scatter radiation reaching the image receptor (Correct answer)
- Magnify the image
- Decrease exposure time
Correct answer: Reduce scatter radiation reaching the image receptor
Grids are placed between the patient and image receptor to absorb scattered radiation, improving image contrast.
Question 3: Which of the following describes the ALARA principle?
- As Low As Reasonably Achievable (Correct answer)
- As Large As Radiographically Acceptable
- Automatic Low Amplitude Radiation Adjustment
- Allowable Limit of Annual Radiation Accumulation
Correct answer: As Low As Reasonably Achievable
ALARA stands for As Low As Reasonably Achievable, guiding practitioners to minimize radiation exposure while maintaining diagnostic image quality.
Question 4: What does mAs represent in radiographic technique?
- Milliamperes per second squared
- Milliampere-seconds, a measure of X-ray quantity (Correct answer)
- Maximum allowable shielding
- Minimum attenuation standard
Correct answer: Milliampere-seconds, a measure of X-ray quantity
mAs (milliampere-seconds) is the product of tube current (mA) and exposure time (s), determining the total quantity of X-rays produced.
Question 5: Which type of X-ray interaction with matter predominates at diagnostic energy levels in soft tissue?
- Pair production
- Photoelectric effect
- Compton scatter (Correct answer)
- Coherent scatter
Correct answer: Compton scatter
Compton scatter is the dominant interaction at typical diagnostic X-ray energies in soft tissue, contributing to image noise and patient dose.
Question 6: What is the function of the anode in an X-ray tube?
- Emit electrons via thermionic emission
- Receive electrons and produce X-rays (Correct answer)
- Filter low-energy photons
- Collimate the X-ray beam
Correct answer: Receive electrons and produce X-rays
The anode (target) receives high-speed electrons from the cathode, converting a small fraction of their kinetic energy into X-rays.
Question 7: A radiograph appears too light (underexposed). Which adjustment would most directly correct this?
- Decrease kVp
- Decrease mAs
- Increase mAs (Correct answer)
- Increase SID
Correct answer: Increase mAs
Increasing mAs raises the quantity of X-rays produced, resulting in greater film blackening or detector signal and a properly exposed image.
Radiography Exam Radiology Tech 2
Which unit is used to measure radiation absorbed dose in SI units?