OHIO GXMO STUDY GUIDE REVIEW, GXMO OHIO
REVIEW INFO (QUESTIONS FROM STUDY GUIDE
FROM GXMO CLASS.) 2024 QUESTIONS &
ANSWERS RATED A+
Introduction
This Ohio GXMO (General X-ray Machine Operator) Study Guide Review simulates the
2024 state licensing examination.
The review covers six weighted domains: radiation physics & safety, x-ray equipment
operation, patient positioning & imaging procedures, image production & quality
assurance, Ohio administrative code compliance, and patient care/ethics.
Every item is original, scenario-based, and aligned with Ohio Department of Health
(ODH) Chapter 3701-72 requirements to support mastery-level performance on the
actual 75-question computer-delivered exam.
Exam-length set: 75 original questions
Question 1:
The leakage radiation from an x-ray tube housing must not exceed
A. 0.25 mGy air-kerma in any one hour at 1 m
B. 0.5 mR in any one hour at 50 cm
C. 1 mGy per week at the operator’s position
D. 5 µSv per patient exposure
Answer: A. 0.25 mGy air-kerma in any one hour at 1 m
Solution: Ohio adopts the federal limit of 0.25 mGy (≈25 mR) air-kerma in one hour at
one metre from the focal spot. Options B, C, and D exceed or mis-state the mandated
leakage limit.
Question 2:
A mobile radiograph is ordered on a patient in contact isolation. Which action best
maintains radiation protection standards?
A. Cover the PID with a sterile drape but leave the exposure cord uncovered
B. Place a lead apron only on the patient, not on the cassette
C. Employ the longest possible SID and the highest kVp consistent with contrast goals
D. Increase mAs 30 % to avoid repeat exposures
Answer: C. Employ the longest possible SID and the highest kVp consistent with
contrast goals
pg. 1
,Solution: Increasing SID reduces entrance skin dose; higher kVp allows lower mAs,
further lowering dose. Option A leaves the cord contaminated, B ignores operator
shielding, and D unnecessarily increases patient dose.
Question 3:
According to Ohio Admin. Code 3701-72-04, a GXMO must notify the Department of
Health within ____ days of a radiation equipment theft.
A. 1
B. 3
C. 5
D. 30
Answer: A. 1
Solution: Rule 3701-72-04(C) mandates the next calendar day. Options B, C, and D are
common grace periods for other events (equipment relocation, shielding plan changes,
etc.) but not for theft.
Question 4:
Which interaction contributes most to patient dose in general radiography performed at
90 kVp?
A. Coherent scatter
B. Photoelectric effect
C. Compton scatter
D. Pair production
Answer: C. Compton scatter
Solution: At 90 kVp, Compton events dominate; absorbed energy from Compton
electrons contributes to dose. Photoelectric is significant below 50 kVp; pair production
needs ≥1.02 MeV.
Question 5:
An image shows a 1.5 cm focal-spot blur when the SID is 100 cm and OID is 25 cm. The
true focal-spot size is approximately
A. 0.3 mm
B. 0.6 mm
C. 1.0 mm
D. 1.2 mm
Answer: B. 0.6 mm
Solution: Geometric blur formula: focal-spot = blur × (SID – OID) / OID. 1.5 cm × (100 –
25) / 25 = 4.5 cm / 25 = 0.18 cm ≈ 0.6 mm when converted and rounded.
pg. 2
, Question 6:
The primary purpose of a collimator light-localiser is to
A. Reduce patient motion
B. Align the radiation field with the image receptor
C. Increase contrast resolution
D. Calibrate automatic exposure control
Answer: B. Align the radiation field with the image receptor
Solution: Collimator light visually defines the x-ray field, ensuring full anatomic
coverage while minimising dose. It does not address motion (A), intrinsic contrast (C),
or AEC calibration (D).
Question 7:
Which grid error most severely reduces optical density on the radiograph?
A. 8° lateral decentering
B. 5° focal-distance off-level
C. Upside-down grid
D. 15 % decrease in SID within grid focus range
Answer: C. Upside-down grid
Solution: An inverted grid causes severe grid-cut-off, producing a uniformly light image.
Other errors create partial cut-off but still transmit more primary beam.
Question 8:
During a lateral cervical spine exam, the shoulders are impossible to depress. The GXMO
should
A. Angle the central ray 15° cephalad
B. Increase exposure time to minimise motion
C. Angle the central ray 5–10° caudad
D. Perform the study supine instead
Answer: C. Angle the central ray 5–10° caudad
Solution: Caudad angulation projects the shoulders inferiorly, opening C7-T1 while
maintaining the lateral position. Cephalad angulation (A) would over-project the
clavicles.
Question 9:
A quality-control test using a slit camera is performed to measure
A. kVp accuracy
B. Half-value layer
C. Focal-spot size
D. Automatic brightness control
Answer: C. Focal-spot size
pg. 3
REVIEW INFO (QUESTIONS FROM STUDY GUIDE
FROM GXMO CLASS.) 2024 QUESTIONS &
ANSWERS RATED A+
Introduction
This Ohio GXMO (General X-ray Machine Operator) Study Guide Review simulates the
2024 state licensing examination.
The review covers six weighted domains: radiation physics & safety, x-ray equipment
operation, patient positioning & imaging procedures, image production & quality
assurance, Ohio administrative code compliance, and patient care/ethics.
Every item is original, scenario-based, and aligned with Ohio Department of Health
(ODH) Chapter 3701-72 requirements to support mastery-level performance on the
actual 75-question computer-delivered exam.
Exam-length set: 75 original questions
Question 1:
The leakage radiation from an x-ray tube housing must not exceed
A. 0.25 mGy air-kerma in any one hour at 1 m
B. 0.5 mR in any one hour at 50 cm
C. 1 mGy per week at the operator’s position
D. 5 µSv per patient exposure
Answer: A. 0.25 mGy air-kerma in any one hour at 1 m
Solution: Ohio adopts the federal limit of 0.25 mGy (≈25 mR) air-kerma in one hour at
one metre from the focal spot. Options B, C, and D exceed or mis-state the mandated
leakage limit.
Question 2:
A mobile radiograph is ordered on a patient in contact isolation. Which action best
maintains radiation protection standards?
A. Cover the PID with a sterile drape but leave the exposure cord uncovered
B. Place a lead apron only on the patient, not on the cassette
C. Employ the longest possible SID and the highest kVp consistent with contrast goals
D. Increase mAs 30 % to avoid repeat exposures
Answer: C. Employ the longest possible SID and the highest kVp consistent with
contrast goals
pg. 1
,Solution: Increasing SID reduces entrance skin dose; higher kVp allows lower mAs,
further lowering dose. Option A leaves the cord contaminated, B ignores operator
shielding, and D unnecessarily increases patient dose.
Question 3:
According to Ohio Admin. Code 3701-72-04, a GXMO must notify the Department of
Health within ____ days of a radiation equipment theft.
A. 1
B. 3
C. 5
D. 30
Answer: A. 1
Solution: Rule 3701-72-04(C) mandates the next calendar day. Options B, C, and D are
common grace periods for other events (equipment relocation, shielding plan changes,
etc.) but not for theft.
Question 4:
Which interaction contributes most to patient dose in general radiography performed at
90 kVp?
A. Coherent scatter
B. Photoelectric effect
C. Compton scatter
D. Pair production
Answer: C. Compton scatter
Solution: At 90 kVp, Compton events dominate; absorbed energy from Compton
electrons contributes to dose. Photoelectric is significant below 50 kVp; pair production
needs ≥1.02 MeV.
Question 5:
An image shows a 1.5 cm focal-spot blur when the SID is 100 cm and OID is 25 cm. The
true focal-spot size is approximately
A. 0.3 mm
B. 0.6 mm
C. 1.0 mm
D. 1.2 mm
Answer: B. 0.6 mm
Solution: Geometric blur formula: focal-spot = blur × (SID – OID) / OID. 1.5 cm × (100 –
25) / 25 = 4.5 cm / 25 = 0.18 cm ≈ 0.6 mm when converted and rounded.
pg. 2
, Question 6:
The primary purpose of a collimator light-localiser is to
A. Reduce patient motion
B. Align the radiation field with the image receptor
C. Increase contrast resolution
D. Calibrate automatic exposure control
Answer: B. Align the radiation field with the image receptor
Solution: Collimator light visually defines the x-ray field, ensuring full anatomic
coverage while minimising dose. It does not address motion (A), intrinsic contrast (C),
or AEC calibration (D).
Question 7:
Which grid error most severely reduces optical density on the radiograph?
A. 8° lateral decentering
B. 5° focal-distance off-level
C. Upside-down grid
D. 15 % decrease in SID within grid focus range
Answer: C. Upside-down grid
Solution: An inverted grid causes severe grid-cut-off, producing a uniformly light image.
Other errors create partial cut-off but still transmit more primary beam.
Question 8:
During a lateral cervical spine exam, the shoulders are impossible to depress. The GXMO
should
A. Angle the central ray 15° cephalad
B. Increase exposure time to minimise motion
C. Angle the central ray 5–10° caudad
D. Perform the study supine instead
Answer: C. Angle the central ray 5–10° caudad
Solution: Caudad angulation projects the shoulders inferiorly, opening C7-T1 while
maintaining the lateral position. Cephalad angulation (A) would over-project the
clavicles.
Question 9:
A quality-control test using a slit camera is performed to measure
A. kVp accuracy
B. Half-value layer
C. Focal-spot size
D. Automatic brightness control
Answer: C. Focal-spot size
pg. 3
