Radiology Physics Self Assessment Quiz

Module 1: Basic Science – Structure of the Atom, Electromagnetic (EM) Radiation, and Particulate Radiation

Q1. Elements which have the same Z (atomic number) but different A (mass number) are called:

• A. Isobars
• B. Isomers
• C. Isotones
• D. Isotopes
• Answer: D – Isotopes PDF
• Explanation: Isotopes are forms of the same element, and thus have the same atomic number Z (the number of protons), but have a different number of neutrons, thus different mass number A (neutrons plus protons). Isobars have the same A but different Z. Isomers have the same A and Z, but different energy states. Isotones have the same number of neutrons but different Z. Isotopes and isomers are common concepts in radiology. PDF

Q2. The mass number (A) of an atom is equal to the number of:

• A. Neutrons
• B. Protons
• C. Neutrons and protons PDF
• D. Protons and electrons
• Answer: C – Neutrons and protons PDF
• Explanation: The mass number is defined as the number of nucleons (protons and neutrons) in the atomic nucleus. PDF

Q3. The binding energy of an electron in the K-shell is:

• A. The energy the electron needs to stay in the K-shell
• B. The energy needed for an electron to make a transition from the K-shell to L-shell
• C. The energy needed for an electron to transition from the L-shell to K-shell
• D. The energy needed to remove an electron in the K-shell from the atom PDF
• Answer: D – The energy needed to remove an electron in the K-shell from the atom. PDF
• Explanation: The K-shell binding energy is the energy to ionize the atom by removing the K-shell electron. PDF

Q4. A proton is electrostatically repelled by:

• A. Electrons
• B. Neutrons
• C. Photons
• D. Neutrinos
• E. Alphas PDF
• Answer: E – Alphas PDF
• Explanation: As a proton, a positron, and an alpha particle are all positively charged particles (while an electron is negatively charged and a neutron is neutral), a proton will be repelled by both a positron and an alpha particle. PDF

Q5. Which of the following modalities uses only non-ionizing radiation to generate an image?

• A. Fluoroscopy
• B. Mammography
• C. MRI PDF
• D. CT
• Answer: C – MRI PDF
• Explanation: MRI uses radio waves, while all other modalities use ionizing radiation. PDF

Q6. Which of the following is an example of particulate radiation?

• A. Microwaves
• B. X-rays
• C. Alpha particles PDF
• D. Gamma rays
• Answer: C – Alpha particles PDF
• Explanation: Microwaves, x-rays, and gamma rays are all forms of electromagnetic radiation. Only alpha particles are particulate. PDF

Q7. A radiation detector records a reading when an unshielded detector is swept over a spill, but no reading when a shielded detector is swept over the spill. What does this tell us about the spilled substance?

• A. The substance is not radioactive since it did not register in both orientations.
• B. The substance emits high-energy photons since it only registered when unshielded.
• C. The substance emits particulate radiation or very low-energy photons since it only registered when unshielded. PDF
• D. The substance has a very long half-life because the meter did not register when shielded.
• Answer: C – The substance emits particulate radiation or very low-energy photons since it only registered when unshielded. PDF
• Explanation: Particulate or very low-energy photons will be absorbed in the shielding and will not register (or barely register) in the detector. When unshielded, the energy is deposited in the detector. Particulate radiation has a limited range and will not pass through a shielded detector. PDF

Q8. A person accidentally ingests an unknown radioactive substance that is subsequently permanently bound to his bony tissues (biological half life > 20 years). If this individual lives in close proximity to his or her family, which of the following types of radiation is the greatest safety concern for the family?

• A. Photons (>100 keV) PDF
• B. Neutrinos
• C. Electrons (30 keV)
• D. Alpha particles
• Answer: A – Photons (>100 keV) PDF
• Explanation: Low-energy electrons and alpha particles all have relatively short ranges in human tissue, and thus most or all of these particles will be absorbed by the person and will not reach the family to cause radiation damage. Neutrinos have very little interaction with tissue. PDF

Q9. Radionuclides used for nuclear medicine imaging must include one of the following emissions:

• A. Electrons
• B. Alpha particles
• C. Gamma rays PDF
• D. Protons
• Answer: C – Gamma rays PDF
• Explanation: Particulate radiations such as electrons, alphas and protons have a limited range in human tissue. The particles will be absorbed within the body and will not reach an external imaging detector. Gamma rays are more penetrating and undergo relatively fewer interactions within the body allowing detection by an external detector. PDF

Q10. The number of electrons in a neutral atom is the:

• A. Mass defect
• B. Mass number
• C. Atomic number PDF
• D. Binding Energy
• Answer: C – Atomic number PDF
• Explanation: The atomic number is defined to be the number of protons within the nucleus. For a neutral atom the number of negatively charged orbital electrons is equal to the number of positively charged protons in the nucleus. PDF

Q11. What is the likely result when an electron vacancy in the K-shell is filled by an electron from the L-shell?

• A. Annihilation radiation
• B. Gamma ray
• C. Characteristic x-ray PDF
• D. Neutrino
• Answer: C – Characteristic x-ray PDF
• Explanation: Electron transition between atomic energy shells results in the emission of a characteristic x-ray photon. The energy of the x-ray photon is equal to the difference between the binding energy of the respective shells. Since atomic binding energies are unique to each element, the energy of the x-ray characteristic for that element. PDF

Module 2: Interactions of Ionizing Radiation with Matter

Q1. What is the predominant interaction of 120 kV x-rays from a computed tomography scanner with soft tissue?

• A. Coherent scattering
• B. Compton scattering PDF
• C. Photoelectric effect
• D. Pair production
• Answer: B – Compton scattering PDF
• Explanation: Above 25 keV, Compton scatter is the dominant photon interaction in soft tissue. Because CT x-ray beams have higher filtration than radiographic units, the effective energy is closer to one-half of the kV (60 keV). PDF

Q2. If a radiologic technologist uses 80 kV for the AP projection of the lumbar spine, which of the following interactions will be the predominant interaction with bone?

• A. Coherent scattering
• B. Compton scattering
• C. Photoelectric effect PDF
• D. Pair production
• Answer: C – Photoelectric effect PDF
• Explanation: The average energy for an 80 kV spectrum is typically 1/3 to 1/2 of the maximal energy. X-ray photons in this range interact primarily by photoelectric interaction with bone. The primary interaction in this range (25-40 keV) with soft tissue is Compton scattering. PDF

Q3. During imaging of a patient, the proportion of Compton scatter is increased by increasing which of the following technical parameters?

• A. Exposure time
• B. Focal spot size
• C. kV PDF
• D. Source-to-image receptor distance
• Answer: C – kV PDF
• Explanation: The proportion of Compton scattering compared to photoelectric interactions increases with an increase in x-ray beam energy (kV, filtration). PDF

Q4. Which of the following interactions is primarily responsible for patient dose in the low diagnostic energy range?

• A. Coherent scattering
• B. Compton scattering
• C. Photoelectric effect PDF
• D. Pair production
• Answer: C – Photoelectric effect PDF
• Explanation: Absorbed dose is energy absorbed per unit mass. In photoelectric effect, the incoming photon is completely absorbed locally. PDF

Q5. The predominant interaction of Tc-99m photons with a sodium iodide crystal is:

• A. Coherent scattering
• B. Compton scattering
• C. Photoelectric effect PDF
• D. Pair production
• Answer: C – Photoelectric effect PDF
• Explanation: Tc-99m gamma photons have energy of 140 keV. At this energy more than 50% of the interactions are photoelectric. PDF

Q6. The unit for linear energy transfer (LET) is:

• A. keV per um PDF
• B. keV per density
• C. keV per mg
• D. keV per g
• Answer: A – keV per um PDF
• Explanation: Linear energy transfer is the average amount of energy deposited locally per unit path length. Do not confuse the units of LET with the units of absorbed dose, which is energy absorbed per mass. Increases in LET increase the radiation weighting factor. PDF

Q7. In interactions of x-ray and gamma ray radiation with matter, the occurrence of a sharp increase in photoelectric absorption is related to:

• A. density increases
• B. density decreases
• C. the photon energy being just above the atomic number of the substance
• D. the photon energy being just above the electron binding energy PDF
• Answer: D – the photon energy being just above the electron binding energy. PDF
• Explanation: Photoelectric absorption is proportional to Z3/E3, and there is a sharp increase in absorption when the incoming photon energy is slightly above the electron binding energy. PDF

Q8. At 80 kV, assume the soft-tissue HVL is 4 cm. What is the approximate radiation dose to an embryo located 8 cm below the anterior surface, expressed as a percentage of the entrance skin dose?

• A. 100%
• B. 75%
• C. 50%
• D. 25% PDF
• E. 12.5%
• Answer: D – 25% PDF
• Explanation: At 80 kV, the half-value layer for soft tissue is approximately 3 to 4 cm. If the HVL is 3 cm of soft tissue, the embryo radiation dose would be 12.5% of the entrance skin dose. If the HVL is 4 cm of soft tissue, the radiation dose would be 25% of the entrance skin dose. PDF

Q9. Which of the following is the most penetrating of the radiations listed?

• A. Electrons from I-131 radioactive decay
• B. Photons from Tc-99m radioactive decay
• C. Positrons from F-18 radioactive decay
• D. Photons from F-18 radioactive decay PDF
• Answer: D – Photons from F-18 radioactive decay PDF
• Explanation: Penetration increases with energy, and the annihilation radiation at 511 keV is the most penetrating. When comparing between charged particulate radiation and photons of same energy, photons are more penetrating. PDF

Q10. The energy of each photon created when a positron interacts with an electron in an annihilation reaction is:

• A. 5 eV
• B. 140 keV
• C. 511 keV PDF
• D. 1.022 MeV
• E. 3 MeV
• Answer: C – 511 keV PDF
• Explanation: The rest mass of the electron and positron are each 511 keV for a total of 1.022 MeV. When the annihilation reaction occurs, two 511 keV photons are created. PDF

Q11. Which of the following is most damaging to tissue?

• A. Electrons (100 keV)
• B. Photons (diagnostic energy)
• C. Neutrinos
• D. Protons (100 keV) PDF
• Answer: D – Protons (100 keV) PDF
• Explanation: Neutrinos are near massless particles that undergo almost no interactions with any matter. Photons undergo exponential attenuation, and when interactions occur, varying amounts of energy are deposited. Electrons have a finite range with soft/hard collisions. Protons lose little energy due to radiative losses, and the majority of energy is deposited in a small volume close to the end of their range due to the presence of a Bragg peak. PDF

Module 3: Radiation Units

Q1. The unit for effective dose is:

• A. R/min
• B. mGy
• C. mR
• D. mSv PDF
• Answer: D – mSv PDF
• Explanation: None provided in text. PDF

Q2. The absorbed dose multiplied by a weighting factor appropriate for the type of radiation is:

• A. Integral absorbed dose
• B. Equivalent dose PDF
• C. Effective dose
• D. Committed equivalent dose
• Answer: B – Equivalent dose PDF
• Explanation: Equivalent dose is obtained by multiplying the absorbed dose by the radiation weighting factor (WR​), which is a function of the type and energy of the radiation. PDF

Q3. A medical worker receives 30 mGy to an area of skin on the hand from alpha particles. The equivalent dose to this area of skin is:

• A. 30 mGy
• B. 30 mSv
• C. 600 mGy
• D. 600 mSv PDF
• Answer: D – 600 mSv PDF
• Explanation: Equivalent dose (H) = radiation weighting factor (WR​) × absorbed dose (D), where WR​=20 for alpha particles. Equivalent dose is given in Sv. PDF

Q4. Match the following quantities with their SI units (Units: 1. Sievert, 2. Gray, 3. Roentgen, 4. Coulomb per kilogram):

• A. Absorged dose -> Gray PDF
• B. Equivalent dose -> Sievert PDF
• C. Effective dose -> Sievert PDF
• D. Air Kerma -> Gray PDF
• E. Exposure -> Coulomb per kilogram PDF
• Answer: A.2, B.1, C.1, D.2, E.4 PDF

Q5. Which quantity provides a single index that relates to the overall stochastic risk (at diagnostic radiation dose levels) when multiple organs are irradiated?

• A. Absorbed dose
• B. Equivalent dose
• C. Effective dose PDF
• D. Air kerma
• E. Exposure
• Answer: C – Effective dose PDF
• Explanation: Absorbed dose and equivalent dose are used to assess radiation risks to individual organs and tissues. Air kerma and exposure quantify radiation intensity in air but do not provide an overall risk index from multiple tissue/organ irradiation. PDF

Q6. Which statement is true regarding effective dose?

• A. It is dependent on co-morbidities.
• B. It is restricted only to single individual organ or tissue doses.
• C. It is a weighted sum of equivalent doses over multiple organs and tissues. PDF
• D. It is independent of radiation type.
• Answer: C – It is a weighted sum of equivalent doses over multiple organs and tissues. PDF
• Explanation: Tissue weighting factors (WT​) are for average patients, making A incorrect. B is incorrect because effective dose handles multiple or single organs. D is incorrect because equivalent dose includes radiation weighting factors (WR​). PDF

Q7. Convert a dosage of 20 mCi Tc-99m to MBq of Tc-99m:

• A. 0.54 MBq
• B. 20 MBq
• C. 37 MBq
• D. 740 MBq PDF
• Answer: D – 740 MBq PDF
• Explanation: 1 mCi is equal to 37 MBq. PDF

Module 4: X-Ray Production

Q1. What is a direct result of adding filtration to a diagnostic x-ray beam?

• A. All characteristic radiation is removed.
• B. Image contrast is improved.
• C. Maximum photon energy is increased.
• D. X-ray tube heat loading is reduced.
• E. Patient dose is reduced. PDF
• Answer: E – Patient dose is reduced. PDF
• Explanation: Added filters reduce the quantity of low-energy x-ray photons and “harden” the x-ray beam, reducing patient skin dose. PDF

Q2. Which of the following always increases as focal spot size increases?

• A. Field of view
• B. Patient dose
• C. Geometric un-sharpness PDF
• D. Anode diameter
• Answer: C – Geometric un-sharpness PDF
• Explanation: The larger the focal spot size, the greater the geometric un-sharpness when combined with magnification. PDF

Q3. In projection radiography, which of the following will reduce patient skin dose?

• A. Increased filtration PDF
• B. Higher grid ratio
• C. Lower kV
• D. Smaller focal spot size
• Answer: A – Increased filtration PDF
• Explanation: Added filters reduce low-energy x-ray photons (“harden” the beam), reducing patient skin dose. PDF

Q4. With which of the following is the heel effect more pronounced?

• A. Image receptor farther from the focal spot
• B. Large focal spot size
• C. Smaller image size
• D. No grid
• E. X-ray tube with a smaller anode angle PDF
• Answer: E – X-ray tube with a smaller anode angle. PDF
• Explanation: The heel effect is more pronounced when the anode angle is small and the SID is reduced. PDF

Q5. In the figure comparing two x-ray tube spectra, what single parameter was changed between acquisitions? (Low-energy ends same, characteristic peaks same, max energy changed)

• A. kV PDF
• B. Filtration
• C. Target material
• D. mAs
• Answer: A – kV PDF
• Explanation: Same low-energy end indicates same filtration; same characteristic peaks indicate same target material. The maximum energy change occurs only with a change in kV. PDF

Q6. In the figure comparing two x-ray tube spectra, what single parameter was changed between acquisitions? (Low-energy ends same, characteristic peaks same, max energy same, quantity differs)

• A. kV
• B. Filtration
• C. Target material
• D. mAs PDF
• Answer: D – mAs PDF
• Explanation: Filtration, target material, and kV (maximum energy) remained identical. The only change is x-ray quantity, indicating a change in mAs. PDF

Module 5: General Imaging and Informatics Concepts

Q1. The image of the CT phantom is used to measure which image property?

• A. Spatial resolution PDF
• B. Noise
• C. Dose
• D. Temporal resolution
• Answer: A – Spatial resolution PDF
• Explanation: High-contrast spatial resolution or bar phantoms use alternating opaque/translucent bars to find the limiting spatial resolution. PDF

Q2. What metric evaluates the spatial resolution of an imaging system with change in spatial frequency?

• A. Modulation transfer function PDF
• B. Point spread function
• C. Noise frequency
• D. Signal-to-noise ratio
• Answer: A – Modulation transfer function PDF
• Explanation: The MTF is a measure of spatial resolution describing the percentage of output signal contrast relative to input signal contrast as a function of spatial frequency. PDF

Q3. The CT image shown is viewed at a window width of 2 HU and level of 2 HU. What single change below could be made to make the image more suitable for diagnostic viewing?

• A. Increase window width PDF
• B. Decrease window width
• C. Increase window level
• D. Decrease window level
• Answer: A – Increase window width PDF
• Explanation: A window width of 2 HU maps everything into extreme black or white, losing soft-tissue differentiation. Increasing window width improves soft-tissue contrast. PDF

Q4. Which of the following is increased in the image on the right? (Grainier appearance)

• A. Noise PDF
• B. Dose
• C. Contrast
• D. Blur
• Answer: A – Noise PDF
• Explanation: Grainier appearance indicates increased noise. PDF

Q5. Match outlined regions to histogram peaks (-800 HU, -100 HU, 100 HU):

• Answer: 1. Air and Lung (HU < -700) -> A; 2. Contrast-enhanced liver (HU ~80) -> C; 3. Visceral fat (HU ~-100) -> B. PDF

Q6. Given original image and Fourier Transform, which image corresponds to a high-pass filter applied to the Fourier Spectrum?

• A. Image A PDF
• B. Image B
• C. Image C
• D. Image D
• Answer: A PDF
• Explanation: High-pass filters discard low spatial frequencies, leaving only edges (high frequencies). PDF

Q7. The definition of segmentation in medical image processing is:

• A. Reduction of pixel intensity variations by averaging adjacent pixels
• B. Identification of the pixels that compose a structure of interest in an image PDF
• C. Eliminating low spatial frequencies from the image
• D. Altering the relative intensities of the image pixels
• Answer: B – Identification of the pixels that compose a structure of interest in an image. PDF
• Explanation: A is blurring, C is high-pass filtering, D is windowing. Segmentation identifies the structural pixels. PDF

Q8. Detection of a large, low-contrast object in a noisy image can be improved by:

• A. Applying edge enhancement
• B. Applying image smoothing PDF
• C. Increasing window width
• D. Digitally magnifying the image
• Answer: B – Applying image smoothing PDF
• Explanation: Smoothing reduces noise without reducing contrast for large objects, improving detectability. PDF

Q9. What type of CT image is shown? (Multiple layers of rib and lung vessels visualized on one section)

• A. MIP PDF
• B. Surface render
• C. Volume render
• D. MPR
• E. Fused image
• Answer: A – MIP PDF
• Explanation: A maximum-intensity projection displays the brightest value for each pixel across several CT sections. PDF

Q10. Match test statistic regions to True Positive, True Negative, False Positive:

• Answer: I. True Positive – Regions C & D; II. True Negative – Region A; III. False Positive – Regions B & C. PDF

Module 6: Biological Effects of Ionizing Radiation

Q1. Which of the following has the highest LET?

• A. Alpha particle PDF
• B. Gamma ray
• C. X-ray
• D. Beta particle
• Answer: A – Alpha particle PDF
• Explanation: Alpha particles have high LET due to their relatively large mass and higher charge. PDF

Q2. In which phase of the reproductive cycle are cells most sensitive to the damaging effects of radiation?

• A. G1 phase
• B. S phase
• C. G2 phase
• D. M phase PDF
• Answer: D – M phase PDF
• Explanation: Mitosis (M phase) is the most sensitive phase due to lack of a checkpoint before DNA duplication, fewer resistive mechanisms, and exposed DNA targets. PDF

Q3. Most radiation-induced injury is due to damage to which type of molecules?

• A. Deoxyribonucleic acid PDF
• B. Ribonucleic acid
• C. DNA polymerase
• D. Hemoglobin
• Answer: A – Deoxyribonucleic acid PDF
• Explanation: Biological effects like cell killing, carcinogenesis, and mutation result from double-stranded breaks (DSB) in DNA. PDF

Q4. Which of the following is a stochastic effect of radiation?

• A. Hair loss
• B. Skin erythema
• C. Cataract
• D. Carcinogenesis PDF
• Answer: D – Carcinogenesis PDF
• Explanation: Carcinogenesis is a stochastic (statistical probability) effect, whereas hair loss, erythema, and cataracts are deterministic tissue reactions. PDF

Q5. What is the LD50/60​ for humans?

• A. 1 gray
• B. 2 gray
• C. 3 gray
• D. 4 gray PDF
• Answer: A (Listed as 4 gray in explanation text) PDF
• Explanation: LD50/60​ is the whole-body radiation dose causing 50% of irradiated subjects to die within 60 days without medical intervention (4 Gy). PDF

Q6. What is a potential risk to the fetus from a pelvic CT exam acquired during the 30th week of gestation?

• A. Fetal malformation
• B. Prenatal death
• C. Childhood cancer PDF
• D. Cataracts
• Answer: C – Childhood cancer PDF
• Explanation: At 30 weeks (third trimester), the risk is from stochastic effects (childhood cancer), as the dose is well below deterministic thresholds. PDF

Q7. What is the most radiosensitive organ in young women?

• A. Breast PDF
• B. Brain
• C. Gonads
• D. Skin
• Answer: A – Breast PDF
• Explanation: Breast tissue has a tissue weighting factor of 0.12 and high radiosensitivity, especially in younger women. PDF

Q8. What dose-response model does the BEIR VII report recommend for calculating the risk of solid tumor induction from ionizing radiation?

• A. Linear-quadratic
• B. Linear, threshold
• C. Linear, no-threshold PDF
• D. Radiation hormesis
• Answer: C – Linear, no-threshold PDF
• Explanation: Epidemiological data supports the linear, no-threshold (LNT) model for solid tumors (while linear-quadratic is used for leukemia). PDF

Q9. Match radiation dose to acute radiation syndrome stage: A. 3 Gy, B. 12 Gy, C. 50 Gy

• Answer: A.1 (Hematopoietic Syndrome), B.3 (Gastrointestinal Syndrome), C.2 (Neurovascular Syndrome). PDF

Q10. What is the equivalent dose to a patient from 10 mGy of alpha particles?

• A. 0.5 mSv
• B. 10 mSv
• C. 50 mSv
• D. 200 mSv PDF
• Answer: D – 200 mSv PDF
• Explanation: Radiation weighting factor of alpha particles is 20 (10 mGy×20=200 mSv). PDF

Module 7: Radiation Protection and Associated Regulations

Q1. What is the yearly effective dose limit for radiologists under current regulations?

• A. 10 mSv
• B. 50 mSv PDF
• C. 100 mSv
• D. 0.5 mSv
• E. 1.0 mSv
• Answer: B – 50 mSv PDF
• Explanation: Annual occupational effective dose limit is 50 mSv. PDF

Q2. By what factor has the yearly natural background radiation received per capita changed over time (NCRP Reports 93 and 160)?

• A. Increased by a factor of two
• B. Increased by a factor of four
• C. Increased by a factor of six
• D. Stayed the same PDF
• E. Decreased
• Answer: D – Stayed the same PDF
• Explanation: Natural background effective dose stayed approximately the same at ~3 mSv per year. PDF

Q3. What percentage of average yearly effective dose to the U.S. population is from medical sources?

• A. 10%
• B. 25%
• C. 50% PDF
• D. 75%
• E. 90%
• Answer: C – 50% PDF
• Explanation: Medical sources contribute ~3.0 mSv out of a total ~6.2 mSv per capita per year (NCRP Report 160). PDF

Q4. Which of the following organizations is an advisory body?

• A. U.S. Nuclear Regulatory Commission (NRC)
• B. Food and Drug Administration (FDA)
• C. National Council on Radiation Protection and Measurement (NCRP) PDF
• D. U.S. Department of Transportation (DOT)
• Answer: C – National Council on Radiation Protection and Measurement (NCRP) PDF
• Explanation: NCRP makes non-regulatory recommendations, whereas NRC, FDA, and DOT are regulatory agencies. PDF

Q5. As reported in NCRP Report 160, which category contributes the highest percentage to the total annual dose per capita?

• A. Internal
• B. Radon
• C. Cosmic
• D. Medical PDF
• Answer: D – Medical PDF
• Explanation: Medical contributes 3.0 mSv/yr, whereas radon contributes ~2.3 mSv/yr. PDF

Q6. What type of radiation badge is typically worn by a radiologist?

• A. Block dosimeter
• B. Scintillation detector
• C. Geiger-Müller (GM) detector
• D. Optically stimulated luminescence (OSL) dosimeter PDF
• Answer: D – Optically stimulated luminescence (OSL) dosimeter PDF
• Explanation: OSL dosimeters are the most common personnel monitoring badges. PDF

Q7. What would be the first thing to do when a critically injured person, who may have been contaminated with radioactive material, enters the emergency department?

• A. Remove clothing and wrap in a sheet.
• B. Rinse the person with lukewarm water.
• C. Respond and treat the injury. PDF
• D. Do blood work to determine the possible dose.
• Answer: C – Respond and treat the injury. PDF
• Explanation: Treatment of life- or limb-threatening conditions takes precedence over decontamination. PDF

Q8. Which of the following constitutes a medical event?

• A. 5 mCi of Tc99m sulfur colloid to the wrong patient
• B. 0.3 mCi of I-131 NaI rather than 0.3 mCi I-123 NaI for uptake on a hyperthyroid patient PDF
• C. 30 mCi rather than the standard 8 mCi of Tc99m sestamibi for a cardiac study
• D. 20 mCi of sestamibi rather than 20 mCi of MDP to the correct patient
• Answer: B – 0.3 mCi of I-131 NaI rather than 0.3 mCi I-123 NaI for uptake on a hyperthyroid patient PDF
• Explanation: Defined by administration errors like wrong radiopharmaceutical (I-131 vs I-123) meeting dose threshold criteria. PDF

Q9. Which of the following studies requires more than a 24 hour interruption in breastfeeding?

• A. 10 mCi F-18 FDG
• B. 4 mCi Tc99m pertechnetate
• C. 20 mCi Rb82 chloride
• D. 0.5 mCi In-111 white blood cells PDF
• Answer: D – 0.5 mCi In-111 white blood cells PDF
• Explanation: In-111 blood cells require a longer cessation of breastfeeding compared to rapidly decaying or non-expressed agents. PDF

Q10. What would be the instrument of choice for determining the location of a Tc99m radioactive spill?

• A. Nal well counter
• B. Portable ionization chamber
• C. Geiger-Müller survey meter PDF
• D. Radionuclide calibrator
• Answer: C – Geiger-Müller survey meter PDF
• Explanation: GM survey meter is the most sensitive handheld detector for low-level contamination. PDF

Q11. If a written directive is required for a procedure, the radiologist ordering the procedure must be approved for which category of use?

• A. 10 CFR 35.100
• B. 10 CFR 35.200
• C. 10 CFR 35.300 PDF
• D. 10 CFR 35.500
• Answer: C – 10 CFR 35.300 PDF
• Explanation: Subpart E: Unsealed Byproduct Material requiring a written directive. PDF

Q12. Which of the following may be held for decay in storage until background levels are obtained?

• A. Cobalt 57 marker source
• B. Cesium 137 reference source
• C. Gadolinium 153 transmission rod
• D. Iodine 125 seed for breast localization PDF
• Answer: D – Iodine 125 seed for breast localization PDF
• Explanation: I-125 has a half-life of 60 days (qualifies for decay in storage ≤120 days). PDF

Q13. To authorize the release of a patient treated with a therapeutic dosage of radioactive material, the dose to the most likely exposed individual must be less than what value?

• A. 0.1 mSv
• B. 0.5 mSv
• C. 1 mSv
• D. 5 mSv PDF
• Answer: D – 5 mSv PDF
• Explanation: Per 10 CFR 35.75, total effective dose equivalent to any individual must not exceed 5 mSv. PDF

Q14. A patient has an endoleak, repeated imaging over six months. Cumulative air kerma values recorded are 5 Gy, 5.5 Gy, 7 Gy, and 4.5 Gy. Which agency may require reporting?

• A. Nuclear Regulatory Commission
• B. Food and Drug Administration
• C. Joint Commission PDF
• D. National Council on Radiation Protection
• Answer: C – Joint Commission PDF
• Explanation: Reviewable sentinel event defined as peak skin dose >15 Gy over a period of 6 months to 1 year. PDF

Module 8: General Radiography – Projection Imaging Concepts and Detectors

Q1. What exam is typically performed without an anti-scatter grid?

• A. Lateral Hip
• B. Lateral lumbar spine
• C. AP wrist PDF
• D. AP abdomen
• Answer: C – AP wrist PDF
• Explanation: AP wrist involves low kV, small field size, and thin anatomy, generating minimal scatter, so it is imaged tabletop without a grid. PDF

Q2. What acquisition parameter change will improve low contrast visibility?

• A. Decreasing tube voltage PDF
• B. Increasing SID
• C. Increasing filtration
• D. Decreasing focal spot size
• Answer: A – Decreasing tube voltage PDF
• Explanation: Decreasing tube voltage increases photoelectric absorption, raising subject contrast. PDF

Q3. How would the effect of geometric blur on a radiographic image be minimized?

• A. Use highest mA and shortest exposure time.
• B. Use a small focal spot. PDF
• C. Use largest pixel size.
• D. Use immobilization devices.
• Answer: B – Use a small focal spot PDF
• Explanation: Focal spot blur increases with focal spot size and magnification. PDF

Q4. What is the actual size of an object located halfway between the x-ray tube and image receptor if the object measures 10 mm on the image?

• A. 1 mm
• B. 5 mm PDF
• C. 15 mm
• D. 20 mm
• Answer: B – 5 mm PDF
• Explanation: If SOD is half of SID, magnification factor is 2, meaning the object appears twice as large (10 mm/2=5 mm). PDF

Q5. What is a definition of a Bucky Factor?

• A. Percent contrast improvement with a grid
• B. Relative increase in x-ray intensity when a grid is used PDF
• C. Ratio of grid height to width
• D. Number of grid lines per cm
• Answer: B – Relative increase in intensity when a grid is used PDF

Q6. What is the effect of reducing the SID from 72″ to 40″?

• A. Radiation dose to patient will decrease.
• B. Image spatial resolution will improve.
• C. Image noise will increase.
• D. The object of interest will appear larger on the image. PDF
• Answer: D – The object of interest will appear larger on the image PDF
• Explanation: Decreasing SID increases magnification due to the change in the SID/SOD ratio. PDF

Q7. What parameter change can be made to reduce scatter production in the patient?

• A. Change from 10:1 to 8:1 grid.
• B. Move patient closer to image receptor.
• C. Reduce tube current.
• D. Use a smaller field of view. PDF
• Answer: D – Use a smaller field of view PDF
• Explanation: Smaller field of view irradiates less tissue volume, generating less scatter. PDF

Q8. What type of detector system uses a storage phosphor to capture the x-ray signal?

• A. Indirect Digital Radiography
• B. Direct Digital Radiography
• C. Computed Radiography PDF
• D. Film-screen Radiography
• Answer: C – Computed Radiography PDF
• Explanation: CR uses storage phosphors (barium fluorohalide) that trap electrons until laser stimulation. PDF

Q9. What system element affects spatial resolution in direct radiography flat panel detector systems?

• A. Phosphor thickness
• B. Detector element size PDF
• C. Laser spot size
• D. Field of view
• Answer: B – Detector element size PDF
• Explanation: Smaller detector elements (dexels) yield better spatial resolution. PDF

Q10. What is responsible for the heart appearing enlarged on an AP chest image as compared to a PA chest image?

• A. Focal spot size
• B. Focused grids
• C. Greater scatter closer to tube
• D. Outward divergence of the x-ray beam from focal spot PDF
• Answer: D – Outward divergence of the x-ray beam from the focal spot PDF
• Explanation: Anterior position of the heart makes its SOD smaller in AP projection, increasing magnification. PDF

Q11. What is the reason for excluding high-ratio grid use for mobile radiography?

• A. Poorer scatter rejection.
• B. More difficult to align with the focal spot. PDF
• C. More easily mis-positioned upside down.
• D. Cannot be manufactured with short enough focal lengths.
• Answer: B – More difficult to align with the focal spot PDF
• Explanation: Lack of accurate alignment on portable units leads to grid cutoff. PDF

Q12. A radiograph of a neonate airway was obtained in 1.5X geometric magnification mode. What acquisition parameter is most critical to ensure optimal spatial resolution?

• A. Added filtration
• B. High kV
• C. Small focal spot size PDF
• D. Large SID
• E. High mAs
• Answer: C – Small focal spot size PDF
• Explanation: A 0.3 mm small focal spot is crucial for limiting focal spot blur in magnification modes. PDF

Q13. Identify the artifact in the digital radiography image: (Interference moiré pattern)

• A. Dead pixels
• B. Grid line interference PDF
• C. Grid inserted upside down
• D. Patient motion
• Answer: B – Grid line interference PDF
• Explanation: Occurs from aliasing when grid frequency is comparable to detector pixel sampling rate. PDF

Q14. For a dedicated chest radiography room, the x-ray tube for the wall stand should be set with:

• A. Anode side up and cathode side down PDF
• B. Anode side down and cathode side up
• C. Either anode up or down (makes no difference)
• D. Depends on patient size
• E. Depends on radiologist preference
• Answer: A – Anode side up and cathode side down PDF
• Explanation: Thicker anatomy (diaphragm) should be near cathode, thinner anatomy (neck) near anode (heel effect compensation). PDF

Q15. Under automatic exposure control (AEC), increasing the SID from 40″ to 72″ in radiography results in:

• A. Shorter exposure times
• B. Decreased focal spot blurring PDF
• C. An increase in patient exposure
• D. Noisier images
• Answer: B – Decreased focal spot blurring PDF
• Explanation: Magnification (M=SID/SOD) decreases, reducing focal spot blur. PDF

Q16. Match x-ray procedure to effective dose (Abdomen, Extremities, Two-view mammogram, PA chest, Shoulder):

• Answer: 1. Abdomen (0.7 mSv) -> B; 2. Extremities (0.001 mSv) -> A; 3. Two view mammogram (0.4 mSv) -> E; 4. PA chest (0.02 mSv) -> C; 5. Shoulder (0.01 mSv) -> D. PDF

Q17. How does the spatial resolution of an indirect conversion digital radiography system compare to a direct system?

• A. Better
• B. Equivalent
• C. Worse PDF
• Answer: C – Worse than a direct conversion digital radiography system PDF
• Explanation: Light spread in the scintillator of indirect systems adds blurring, reducing resolution. PDF

Q18. In taking an abdominal radiograph of a pregnant patient, what is the single most important thing to ensure lowest dose to fetus while acquiring appropriate image?

• A. Use high kV
• B. Shield the fetus
• C. Reduce the FOV with collimation PDF
• D. Position prone instead of supine
• E. Remove anti-scatter grid
• Answer: C – Reduce the FOV with collimation PDF
• Explanation: Internal scatter from mother is the main fetal dose source; collimating reduces irradiated tissue volume and scatter. PDF

Q19. For a KUB on an average-sized patient, what would be a reasonable technique?

• A. 75 kV, 20 mAs, 40″ SID PDF
• B. 120 kV, 12 mAs, 40″ SID
• C. 50 kV, 50 mAs, 72″ SID
• D. 75 kV, 2.5 mAs, 72″ SID
• Answer: A – 75 kV, 20 mAs, 40″ SID PDF
• Explanation: Balances moderate kV (adequate contrast), reasonable mAs (low noise), and standard SID. PDF

Module 9: Mammography

Q1. What are the minimal images required for locating a lesion in a stereotactic breast biopsy system?

• A. 3 PDF
• B. 5
• C. 9
• D. 15
• Answer: A (Note: Text explanation mentions scouting followed by two images at +15 and -15 degrees; option A corresponds to 3 total images). PDF

Q2. What is the typical focal spot size for contact mammography?

• A. 3.0 mm
• B. 1.0 mm
• C. 0.3 mm PDF
• D. 0.1 mm
• Answer: C – 0.3 mm PDF
• Explanation: Nominal 0.3 mm large focal spot is used for routine contact images to provide high resolution; 0.1 mm is used for magnification. PDF

Q3. What is the advantage of using low kV?

• A. Low radiation dose
• B. Low exposure time
• C. High subject contrast PDF
• D. High spatial resolution
• Answer: C – High subject contrast PDF
• Explanation: Low kV accentuates attenuation differences between tissues via increased photoelectric effect. PDF

Q4. Which of the following is reduced if inadequate compression pressure is applied?

• A. Scattered radiation
• B. Entrance skin exposure
• C. Geometric blur
• D. Image contrast PDF
• Answer: D – Image contrast PDF
• Explanation: Inadequate compression increases scatter, geometric blur, and dose, resulting in lower image contrast. PDF

Q5. What is the purpose of aligning the cathode with the chest wall and anode with the nipple?

• A. Achieves uniform exposure PDF
• B. Decreases focal spot size
• C. Minimizes motion artifact
• D. Reduces acquisition time
• Answer: A – Achieves uniform exposure PDF
• Explanation: Takes advantage of the heel effect to place highest x-ray intensity over the thickest part (chest wall). PDF

Q6. What could be the cause of degraded image quality seen in the mammogram? (Blurred structures)

• A. Low kV
• B. Motion PDF
• C. Contrast
• D. Noise
• Answer: B – Motion PDF
• Explanation: Patient motion leads to image blurring. PDF

Q7. What artifact is shown (arrow) in the breast axillary region?

• A. Skin fold
• B. Motion
• C. Antiperspirant PDF
• D. Dead pixel
• Answer: C – Antiperspirant PDF
• Explanation: Antiperspirant can mimic calcifications or lesions in the axillary region. PDF

Q8. The pixel size in digital mammography should be less than:

• A. 50 um
• B. 70 um
• C. 100 um PDF
• D. 140 um
• Answer: C – 100 um PDF
• Explanation: Pixel sizes range between 50 and 100 um to detect microcalcifications as small as 100 um. PDF

Q9. What is the most likely cause of the artifact shown? (Light regions with dark speckled areas / underexposure)

• A. Dead pixels
• B. Underexposure PDF
• C. Motion
• D. Antiperspirant
• Answer: B – Underexposure PDF
• Explanation: Low signal-to-noise ratio from underexposure causes amplified noise and speckled light regions. PDF

Q10. What is the radiation dose of 3D tomosynthesis compared to a 2D mammogram?

• A. Comparable PDF
• B. 2 times higher
• C. 3 times higher
• D. 4 or more times higher
• Answer: A – Comparable PDF
• Explanation: Dose is ~1-1.5 mGy AGD, comparable to a digital 2D contact mammogram. PDF

Q11. Which of the following would be used to perform a 2D screening mammogram on a large dense breast?

• A. W/Mo
• B. Mo/Mo
• C. Rh/Rh PDF
• D. W/Al
• Answer: C – Rh/Rh PDF
• Explanation: Large dense breasts require higher energies, achieved using rhodium targets and filters. PDF

Module 10: Fluoroscopy and Interventional Imaging

Q1. What is best practice for kV settings during DSA?

• A. Mask kV higher
• B. Post-contrast kV higher
• C. Mask and post-contrast kV equal PDF
• D. kV variations do not impact DSA quality
• Answer: C – Mask and post-contrast kV equal PDF
• Explanation: Equal kV prevents incomplete subtraction of stationary anatomy caused by attenuation differences. PDF

Q2. What metric best correlates with stochastic risk in fluoroscopy?

• A. Kerma-Area Product (KAP) PDF
• B. Fluoroscopic Exposure Time
• C. Reference Air Kerma
• D. Cumulative Dose
• Answer: A – Kerma-Area Product (KAP) PDF
• Explanation: KAP estimates total x-ray energy imparted to tissues, which relates to stochastic effects. PDF

Q3. What is the goal of the automatic exposure rate control system (AERC)?

• A. Maintain constant patient skin entrance dose rate
• B. Maintain constant dose rate to image receptor PDF
• C. Increase dose rate to image receptor for larger patients
• D. Decrease dose rate to image receptor for smaller patients
• Answer: B – Maintain constant dose rate to image receptor PDF

Q4. Which dose metric reported in fluoroscopy may have units of Gy⋅cm2?

• A. Cumulative dose
• B. Peak skin dose
• C. kerma-area product PDF
• D. Effective dose
• Answer: C – kerma-area product PDF
• Explanation: Units are dose times area (mGy⋅cm2). PDF

Q5. What fluoroscopic mode results in the highest air kerma rate?

• A. Pulsed, 30 pps
• B. Pulsed, 15 pps
• C. Continuous
• D. Cine/Digital Run PDF
• Answer: D – Cine/Digital Run PDF
• Explanation: Cine/digital run results in the highest patient radiation exposure rate. PDF

Q6. Under ABC/AERC in fluoroscopy, which combination results in lowest patient skin entrance dose rate?

• A. High kV, low mA PDF
• B. Low kV, high mA
• C. High kV, high mA
• Answer: A – High kV, low mA PDF
• Explanation: High-kV x-rays are more penetrating, so fewer mA are required to achieve target receptor dose. PDF

Q7. In fluoroscopy, x-ray scatter 1 m from a patient is roughly what percent of patient skin entrance exposure?

• A. 0.001%
• B. 0.01%
• C. 0.1% PDF
• D. 1.0%
• E. 10%
• Answer: C – 0.1% PDF

Q8. Which of the following is a stochastic effect that could occur in a high-dose fluoroscopic procedure?

• A. Erythema
• B. Epilation
• C. Desquamation
• D. Dermal necrosis
• E. Carcinogenesis PDF
• Answer: E – Carcinogenesis PDF
• Explanation: Carcinogenesis is stochastic; the others are deterministic skin effects. PDF

Q9. What is the threshold for The Joint Commission reviewable fluoroscopic sentinel event?

• A. Greater than 2 Gy delivered to a single field
• B. Greater than 2 Gy delivered over all fields
• C. Greater than 15 Gy delivered to a single field PDF
• D. Greater than 15 Gy delivered to all fields
• Answer: C – Greater than 15 Gy delivered to a single field PDF

Q10. Where should the image receptor be positioned in order to minimize patient dose?

• A. Twice the source to patient surface distance
• B. As close to the patient surface as possible PDF
• C. As far from the patient surface as possible
• D. Half the distance to isocenter
• Answer: B – As close to the patient surface as possible PDF
• Explanation: Maximizes receptor signal via inverse square law, requiring less radiation. PDF

Q11. What is the FDA limit for entrance skin exposure rate in high dose rate exposure mode (“boost” mode)?

• A. 87 mGy/s (10 R/s)
• B. 87 mGy/min (10 R/min)
• C. 174 mGy/s (20 R/s)
• D. 174 mGy/min (20 R/min) PDF
• Answer: D – 174 mGy/min (20 R/min) PDF

Q12. What is a typical effective dose from an upper gastrointestinal series?

• A. 0.06 mSv
• B. 0.6 mSv
• C. 6 mSv PDF
• D. 60 mSv
• Answer: C – 6 mSv (range 1.5–12 mSv). PDF+ 1

Q13. Image intensifier (II) type image receptors are most susceptible to what artifact?

• A. Pincushion distortion PDF
• B. Conebeam errors
• C. Dead detector elements
• D. Flat-field artifact
• Answer: A – Pincushion Distortion PDF
• Explanation: Caused by projection onto a curved input surface of an II. PDF

Q14. Flat panel fluoroscopy systems are susceptible to which of the following?

• A. Pincushion Distortion
• B. S-Distortion
• C. Vignetting
• D. Dead Pixels PDF
• Answer: D – Dead Pixels PDF

Q15. Increasing what parameter increases the magnitude of S-distortion?

• A. Receptor dose
• B. kV
• C. Field of view PDF
• D. mA
• Answer: C – Field of view PDF
• Explanation: Deviations in electron trajectories from stray magnetic fields are greatest at the edges of the image intensifier (large FOV). PDF

Module 11: Computed Tomography

Q1. What image quality parameter may be reduced if a patient scan is conducted using tube-current modulation and the localizer image is acquired with the patient positioned below isocenter?

• A. Low-contrast visibility
• B. Detail
• C. Quantum noise PDF
• D. Temporal resolution
• Answer: C – Quantum noise PDF
• Explanation: Positioning below isocenter makes the patient appear larger on the scout, leading to higher tube current, which reduces quantum noise. PDF

Q2. Match American College of Radiology CT Accreditation CTDIvol Dose Reference Levels (75 mGy, 35 mGy, 25 mGy, 15 mGy) to protocols:

• Answer: A.2 (Adult Head – 75 mGy), B.4 (Pediatric Head 1 yr – 35 mGy), C.1 (Adult Body – 25 mGy), D.3 (Pediatric Body 40-50 lbs – 15 mGy). PDF

Q3. An increase in what parameter can improve visibility of low-contrast structures in a CT image without increasing radiation dose?

• A. Tube current
• B. Rotation time
• C. Slice thickness PDF
• D. Increase kV
• Answer: C – Slice thickness PDF
• Explanation: Larger slice thickness increases signal per voxel, reducing noise and improving low-contrast visibility without altering patient dose. PDF

Q4. What parameter was most likely changed from image A to produce image B? (Less noisy vs higher resolution blurring)

• A. Beam energy
• B. Tube current
• C. Gantry angle
• D. Convolution kernel PDF
• Answer: D – Convolution kernel PDF
• Explanation: Changing the convolution kernel (reconstruction filter) alters spatial frequencies, simultaneously affecting noise and resolution. PDF

Q5. What is the cause of the artifact indicated by the arrow in the volume rendered image? (Helix artifact)

• A. Patient motion
• B. Beam hardening
• C. Poor detector calibration PDF
• D. Partial volume averaging
• Answer: C – Poor detector calibration PDF
• Explanation: Appears as a helix on 3D volume renders and partial/full ring artifacts on axial images. PDF

Q6. Which of the following actions would you take to reduce the metal streak artifact in the CT image?

• A. Perform an air calibration
• B. Increase pitch
• C. Increase beam collimation
• D. Increase tube voltage PDF
• Answer: D – Increase tube voltage PDF
• Explanation: Higher x-ray beam energy increases penetration through metal, reducing streak artifacts. PDF

Q7. What acquisition parameter may alter the CT number (Hounsfield Unit)?

• A. mA
• B. Collimation
• C. Rotation time
• D. kV PDF
• Answer: D – kV PDF
• Explanation: Linear attenuation coefficients vary with beam energy and tissue composition. PDF

Q8. What gantry/beam geometry is used in modern multi-detector channel CT scanners?

• A. Translate-rotate
• B. Rotate-rotate PDF
• C. Rotate-stationary
• D. Stationary-translate
• Answer: B – Rotate-rotate PDF

Q9. Match typical CT numbers to healthy tissues (-1000 HU, -120 HU, 140 HU, 800 HU):

• Answer: A.1 (-1000 HU -> Air), B.3 (140 HU -> Contrast-enhanced vessel/bone), C.2 (-120 HU -> Fat), D.4 (800 HU -> Bone/dense structure). PDF

Q10. What CT exam typically results in the highest study CTDIvol?

• A. Routine abdomen
• B. High resolution chest
• C. Cardiac CTA
• D. Brain perfusion PDF
• Answer: D – Brain perfusion PDF
• Explanation: Involves 30 to 50 repeated scans at the same location, yielding CTDIvol values of 150 to 250 mGy. PDF

Q11. According to ACR accreditation standards, at what frequency should CT scanners be tested to evaluate for artifacts?

• A. Daily PDF
• B. Weekly
• C. Monthly
• D. Quarterly
• Answer: A – Daily PDF
• Explanation: Technologist conducts a daily axial scan of a uniform phantom for artifact evaluation. PDF

Q12. What factor influences in-plane spatial resolution?

• A. Detector width
• B. Pitch
• C. Tube voltage
• D. Display field of view PDF
• Answer: D – Display field of view PDF
• Explanation: Selected display FOV determines pixel size; smaller pixels improve in-plane spatial resolution. PDF

Module 12: Ultrasound

Q1. What property in this cyst image causes posterior enhancement?

• A. Increased attenuation
• B. Decreased attenuation PDF
• C. Increased speed of sound
• D. Decreased speed of sound
• Answer: B – Decreased attenuation PDF
• Explanation: Cysts attenuate less and are anechoic, allowing higher-intensity beams to reach tissue behind them, creating a brighter echo (posterior enhancement). PDF

Q2. Determine the attenuation of a 5 MHz ultrasound beam in soft tissue traveling round trip to a depth of 2 cm assuming 100% reflection.

• A. 3 dB
• B. 5 dB
• C. 7.5 dB
• D. 10 dB PDF
• Answer: D – 10 dB PDF
• Explanation: Using rule of thumb (0.5 dB/cm/MHz), Attenuation = 0.5×5 MHz×4 cm total round trip=10 dB. PDF

Q3. What do changes in brightness of the spectral Doppler waveform represent?

• A. Changes blood velocity
• B. Variations in signal intensity PDF
• C. Pulsatile flow
• D. Larger calculated Doppler shift
• Answer: B – Variations in signal intensity PDF
• Explanation: Brightness represents signal intensity, proportional to the number of blood cells moving at that velocity. PDF

Q4. What is a benefit of using harmonic imaging compared to conventional imaging?

• A. Increased mechanical index
• B. Enhanced contrast PDF
• C. Higher frame rates
• D. Better depth information
• Answer: B – Enhanced contrast PDF
• Explanation: Harmonic frequencies remove echo clutter from fundamental reflections, enhancing tissue contrast. PDF

Q5. What is an advantage of using a curvilinear transducer instead of a linear transducer?

• A. Increased attenuation
• B. Improved resolution
• C. Expanded field of view PDF
• D. Higher Frame Rates
• Answer: C – Expanded field of view PDF

Q6. In Doppler ultrasound, what angle is within the preferred range to obtain accurate velocity measurements?

• A. 15 degrees
• B. 25 degrees
• C. 55 degrees PDF
• D. 75 degrees
• Answer: C – 55 degrees (Preferred range is 45 to 60 degrees). PDF+ 1

Q7. Identify the artifact in this ultrasound image: (Comet tail)

• A. Mirror image artifact
• B. Shadowing artifact
• C. Comet tail artifact PDF
• D. Side lobe artifact
• Answer: C – Comet tail artifact PDF
• Explanation: Result of multiple reflections (reverberations) between closely spaced reflectors. PDF

Q8. Identify the artifact seen with gallstones in the figure:

• A. Comet tail
• B. Mirror image
• C. Shadowing PDF
• D. Twinkle
• Answer: C – Shadowing PDF

Q9. Name the artifact identified by the arrow: (Duplication beyond diaphragm)

• A. Mirror image PDF
• B. Speed displacement
• C. Grating lobe
• D. Enhancement
• Answer: A – Mirror image PDF
• Explanation: Arises from multiple beam reflections between a mass and a strong reflector like the diaphragm. PDF

Q10. How does mechanical index depend on transducer frequency?

• A. Proportional to the square
• B. Inversely proportional to the square
• C. Proportional to the square root
• D. Inversely proportional to the square root PDF
• Answer: D – Inversely proportional to the square root PDF
• Explanation: MI is directly proportional to peak rarefactional pressure and inversely proportional to the square root of the frequency. PDF

Q11. What is the wavelength of a 1.5 MHz wave?

• A. 1.5 cm
• B. 1.0 cm
• C. 1.5 mm
• D. 1.0 mm PDF
• E. 1.5 um
• Answer: D – 1.0 mm PDF
• Explanation: Speed of sound (1500 m/s) divided by frequency (1.5 MHz) gives 1.0 mm. PDF

Q12. What is a disadvantage of spatial compounding compared to normal scan mode?

• A. Reduced signal-to-noise ratio
• B. Increased spatial blurring of moving objects PDF
• C. Increased prominence of speckle noise
• D. Reduced depth of penetration
• Answer: B – Increased spatial blurring of moving objects PDF
• Explanation: Persistence of frame averaging reduces temporal resolution and causes blurring of moving structures. PDF

Module 13: Magnetic Resonance Imaging

Q1. What MR pulse sequence timing diagram is illustrated? (90 deg pulse, 180 deg pulse, single echo)

• A. Gradient echo (GRE) sequence
• B. Fast spin echo (FSE) sequence
• C. Echo Planar Imaging (EPI) sequence
• D. Spin echo (SE) sequence PDF
• Answer: D – Spin echo (SE) sequence PDF

Q2. How does scan time change if ETL (Echo Train Length) is increased from 1 to 4?

• A. Quartered PDF
• B. Halved
• C. Doubled
• D. Quadrupled
• Answer: A – Quartered PDF
• Explanation: Acquisition time reduction is inversely proportional to echo train length in FSE sequences. PDF

Q3. Which part of k-space determines image sharpness?

• A. Center of k-space
• B. Peripheral part of k-space PDF
• C. Left half of k-space
• D. Right half of k-space
• Answer: B – Peripheral part of k-space PDF
• Explanation: Center controls SNR/contrast; periphery contributes to high-frequency detail and sharpness. PDF

Q4. According to ACR guidelines, who is allowed unrestricted access to Zone III?

• A. Level 1 MR personnel only
• B. Level 2 MR personnel only
• C. Both Level 1 and Level 2 MR personnel PDF
• D. Neither Level 1 or level 2 MR personnel
• Answer: C – Both Level 1 and Level 2 MR personnel PDF

Q5. What is the most commonly reported adverse event associated with MRI?

• A. Missile events
• B. Implant movement
• C. Thermal injuries PDF
• D. Hearing loss
• Answer: C – Thermal injuries PDF

Q6. According to ACR safe practice guidelines, can a patient with an MR conditional pacemaker be scanned?

• A. Yes, under any conditions
• B. Yes, under specific conditions (e.g., field strength, SAR) PDF
• C. No, never.
• D. Undetermined.
• Answer: B – Yes, the pacemaker may be safely scanned under specific conditions. PDF

Q7. What combination of TE and TR times is used to generate a spin-echo T1-weighted image of the brain?

• A. Short TR, Short TE PDF
• B. Long TR, Long TE
• C. Short TR, Long TE
• D. Long TR, Short TE
• Answer: A – Short TR, Short TE PDF
• Explanation: Short TR provides T1-weighting; very short TE minimizes T2 effects. PDF

Q8. What method of fat suppression results in the greatest reduction in fat signal for a patient with an MR safe metal implant?

• A. Spectral selective fat suppression
• B. STIR technique PDF
• C. Saturation Band
• D. DIXON method
• Answer: B – STIR technique PDF
• Explanation: STIR relies on T1 relaxation times rather than frequency selection, making it robust against field inhomogeneities from metal implants. PDF

Q9. What type of image, when combined with diffusion weighting, would generate contrast in a diffusion-weighted image?

• A. T1 weighting
• B. T2 weighting PDF
• C. T2/T1 weighting
• D. Proton density weighting
• Answer: B – T2 weighting PDF
• Explanation: Strong diffusion gradients extend echo times to 60-100 ms, introducing significant underlying T2 weighting. PDF

Q10. What is the most likely explanation for the ribbon (ghost) artifact observed when using FSE with a body array coil?

• A. Motion artifacts
• B. RF interference
• C. Peripheral signal artifacts PDF
• D. Bad RF coil
• Answer: C – Peripheral signal artifacts PDF
• Explanation: Caused by anatomy within the active volume of the coil but outside the FOV (Annefacts). PDF

Q11. How would you mitigate the susceptibility artifact shown on this gradient echo image?

• A. Use flow suppression
• B. Use a spin echo sequence PDF
• C. Increase TE
• D. Increase TR
• Answer: B – Use a spin echo sequence PDF
• Explanation: The 180-degree RF pulse in spin echo reverses spin dephasing due to field inhomogeneities, making it less sensitive to magnetic susceptibility than gradient echo. PDF

Q12. What artifact is present in the image? (Flow ghosting near vessel)

• A. Patient motion
• B. Flow PDF
• C. RF interference
• D. Gradient failure
• Answer: B – Flow artifact PDF

Q13. What artifact is indicated with the arrow in this axial MPR image? (Ear not covered / wrapping around)

• A. Flow artifact
• B. Gibbs ringing
• C. RF interference
• D. Aliasing PDF
• Answer: D – Aliasing PDF

Q14. How would you correct the aliasing artifact?

• A. Increase TR
• B. Decrease TE
• C. Decrease NEX
• D. Increase FOV PDF
• Answer: D – Increase FOV PDF
• Explanation: Aliasing occurs when object size exceeds FOV; increasing FOV resolves it. PDF

Module 14: Nuclear Medicine

Q1. A licensee may release any individual administered radioactive material if the total effective dose equivalent to any other individual is not likely to exceed what value?

• A. 1 mSv
• B. 5 mSv PDF
• C. 15 mSv
• D. 50 mSv
• Answer: B – 5 mSv (Per 10 CFR 35.75). PDF+ 1

Q2. An incorrect patient weight 100 kg greater than actual weight is entered into a PET scanner. What effect will this have on reported SUV?

• A. Reported SUV value is correct
• B. Reported SUV value greater than correct SUV value PDF
• C. Reported SUV value less than correct SUV value
• Answer: B – Reported SUV value greater than the correct SUV value PDF
• Explanation: Administered activity is in the denominator of the SUV formula; a larger weight reduces the denominator value, increasing the calculated SUV. PDF

Q3. Why does I-131 deliver 100 times more dose to the thyroid per mCi than I-123?

• A. Higher energy Gamma Radiation
• B. Abundance of Beta Radiation PDF
• C. Longer Half Life
• D. Greater Specific Activity
• Answer: B – Abundance of Beta Radiation PDF
• Explanation: I-131 emits energetic beta particles that deposit local dose within less than a centimeter. PDF

Q4. According to NRC regulations, administered activity must be within what percentage of prescribed activity?

• A. 5%
• B. 10%
• C. 15%
• D. 20% PDF
• Answer: D – 20% (Per 10 CFR 35.63(d)). PDF+ 1

Q5. What is the effective half-life of Tc-99m in an organ if its biological half-life is 3 hours? (Physical half-life of Tc-99m = 6 hours)

• A. 2 hours PDF
• B. 3 hours
• C. 6 hours
• D. 9 hours
• Answer: A – 2 hours PDF
• Explanation: 1/Teff​=1/3+1/6=3/6, so Teff​=2 hours. PDF

Q6. What collimator should be used when imaging Indium-111?

• A. Low energy
• B. Medium energy PDF
• C. High energy
• Answer: B – Medium energy PDF
• Explanation: In-111 emits gamma rays at 171 keV and 245 keV; low-energy septae are too thin, while high-energy is less efficient. PDF

Q7. What reconstruction algorithm causes streaking artifact outside the body as indicated by the arrow in the cardiac perfusion image?

• A. Filtered backprojection PDF
• B. Conjugate gradient
• C. Ordered-subset expectation maximization
• D. Bayesian penalization
• Answer: A – Filtered backprojection PDF
• Explanation: Breakdown of ideal assumptions (noise-free, perfect radial sampling) in filtered backprojection leads to positive/negative line streaks. PDF

Q8. The bone image was collected with the camera head placed 30 cm from the body. What can be done to improve spatial resolution?

• A. Increase total counts
• B. Use larger pixel matrix
• C. Move the camera closer to the patient PDF
• D. Apply post-image smoothing filter
• Answer: C – Move the camera closer to the patient PDF
• Explanation: Planar gamma camera spatial resolution is depth-dependent and improves when distance from source decreases. PDF

Q9. What is the cause of the photopenic area at the diaphragm-lung interface on the FDG PET/CT coronal image?

• A. Scatter correction error
• B. Respiratory motion misregistration PDF
• C. Non-attenuation corrected reconstruction
• D. Non-metabolic mass
• Answer: B – Respiratory motion misregistration PDF
• Explanation: Temporal mismatch between CT and PET causes attenuation undercorrection at the liver/diaphragm boundary. PDF

Q10. What can be determined from the image quality of the dynamic planar Tc-99m DTPA study of the kidneys? (Linear streak down image)

• A. Damaged collimator
• B. Improperly tuned photomultiplier tubes PDF
• C. Injection site extravasation
• D. Damaged patient table
• Answer: B – Improperly tuned photomultiplier tubes PDF

Q11. What is the primary reason that 180° RAO-LPO instead of 360° acquisition orbits are used for cardiac SPECT?

• A. Speed up data collection
• B. Reduce attenuation PDF
• C. Improve patient comfort
• D. Permit use of MLEM reconstruction
• Answer: B – Reduce attenuation PDF
• Explanation: Keeps the camera closest to the heart along the chest wall, minimizing distance and attenuation. PDF

Q12. What is the purpose of photomultiplier tubes in nuclear medicine instrumentation?

• A. Detect electron-ion pairs and convert them to current
• B. Convert visible light into electrical signal PDF
• C. Integrate charge to be read out later
• D. Focus gamma rays onto the crystal
• Answer: B – Convert visible light into electrical signal PDF
• Explanation: Photocathodes convert light to electrons, and dynodes amplify the signal. PDF