Radiation Safety Flashcards
A Computed Tomography Dose Index (CTDI) for a CT abdomen on a 5 year old patient should not exceed:
A. 10 mGy
B. 85 mGy
C. 40 mGy
D. 20 mGy
D. 20 mGy
A Computed Tomography Dose Index (CTDI) value exceeding the normal range may have been caused by which three of the following?
A. Incorrect patient identification
B. Incorrect technical settings
C. Inadequate contrast volume
D. Equipment malfunction
E. Large patient
B. Incorrect technical settings
D. Equipment malfunction
E. Large patient
After completing a CT scan, what patient dose information must be recorded and stored?
A. Highest recorded Computed Tomography dose index (CTDI)
B. Cumulative Computed Tomography dose Index (CTDI) for all scan series
C. Computed Tomography dose index (CTDI) and dose-linear product (DLP) for each scan series
D. Total dose-linear product (DLP)
C. Computed Tomography dose index (CTDI) and dose-linear product (DLP) for each scan series
Air kerma is measured in units of:
Gray (Gy), Milligray (mGy)
An increased patient size has what of the following effects on x-ray attenuation?
A. Increased attenuation
B. Decreased attenuation
C. No change in attenuation
A. Increased attenuation
Automatic Tube Current Modulation (ATCM) modifies what technical variable during the CT exposure?
A. mA
B. kVp
C. pitch
D. beam width
A. mA
Based on the information provided in this dose report, what scan may have been performed?
A. CT head without contrast
B. CT head with and without contrast
C. CT abdomen with and without contrast
D. CT abdomen and pelvis without contrast.
C. CT abdomen with and without contrast
Concerning radiation-induced cancer, increasing the radiation dose to a patient results in:
A. Increased severity of cancer
B. Decreased severity of cancer
C. Increase probability of cancer
D. Decreased probability of cancer
C. Increase probability of cancer
Consider the following dose data from three different CT scans. Which procedure has the highest risk of acquiring radiation-induced cancer?
Procedure 1: Absorbed dose= 21 mGy, Effective dose= 11 mSv
Procedure 2: Absorbed dose= 80 mGy, Effective dose= 3 mSv
Procedure 3: Absorbed dose= 34 mGy, Effective dose= 10 mSv
Procedure 1: Absorbed dose= 21 mGy, Effective dose= 11 mSv
Consider this scenario: A medical physicist is scanning a CT phantom with several materials, each having a different atomic number. Which material will cause the least amount of attenuation?
A. Atomic number= 6
B. Atomic number= 19
C. Atomic number= 53
D. Atomic number= 56
A. Atomic number= 6
Consider this scenario: During a CT scan of the chest, the technologist administers a radiation dose of approximately 3,000 milligray (mGy) Which two of the following effects may occur?
A. Cataracts
B. Epilation
C. Cancer
D. Decreased fertility
B. Epilation
C. Cancer
Deterministic effects of radiation exposure include which three of the following? Select three:
A. Skin erythema
B. Epilation
C. Cancer
D. Miscarriage
E. Heritable (genetic effects)
A. Skin erythema
B. Epilation
D. Miscarriage
Dose-linear Product (DLP) is equal to:
A. Computed Tomography Dose Index (CTDI) x scan field of view
B. Computed Tomography Dose Index (CTDI) x scan length
C. Computed Tomography Dose Index (CTDI) x beam width
D. Computed Tomography Dose Index (CTDI) x display field-of-view
B. Computed Tomography Dose Index (CTDI) x scan length
During a CT procedure, attenuation of the x-ray beam may be caused by which three of the following?
A. Coherent scattering
B. Bremssrahlung Radiation
C. Compton scattering
D. Photoelectric absorption
E. Characteristic radiation
A. Coherent scattering
C. Compton scattering
D. Photoelectric absorption
During CT scanning, what part of the patient receives the highest dose of radiation?
A. Center of the patient
B. Surface if the patient
C. Anterior side of the patient
D. Posterior side of the patient
B. Surface if the patient
Effective dose is measured with units of:
Sievert (mSv) or Millisievert (mSv)
Equivalent dose is described with units of:
Sievert or millisievert (mSv)
For deterministic effects of radiation, increasing dose results in:
A. Increased severity of the effect
B. Decreased severity of the effect
C. Increased probability of the effect
D. Decreases probability of the effect
A. Increased severity of the effect
How does decreasing kVp affect patient dose?
A. Increases patient dose
B. Decreases patient dose
C. No change in patient dose
B. Decreases patient dose
How does increasing kVp affect patient dose?
A. Increases patient dose
B. Decreased patient dose
C. No-change in patient dose
A. Increases patient dose
How does increasing mA affect patient dose?
A. Increases patient dose
B. Decreases patient dose
C. No change in patient dose
A. Increases patient dose
How does increasing pitch affect patient dose?
A. Increases patient dose
B. Decreases patient dose
C. No change in patient dose.
B. Decreases patient dose
How will changing the total beam collimation from 8 mm to 16 mm affect patient dose?
A. Increased patient dose
B. Decreased patient dose
C. No change in patient dose
B. Decreased patient dose
If a technologist receives a “dose alert” during a CT scan, he or she should:
A. Notify the patient
B. Notify the ordering physician
C. Review the exposure parameters
D. Review the examination identification
C. Review the exposure parameters
If a technologist receives a “dose alert” during a CT scan, he or she should:
A. Consider reducing the patient dose
B. Consider cancelling the examination
C. Complete a pregnancy test on the patient
D. Complete a creatinine test on the patient
A. Consider reducing the patient dose
If a technologist receives a “dose notification” during a CT scan, he or she should:
A. Consider reducing the patient dose
B. Consider cancelling the examination
C. Complete a pregnancy test on the patient
D. Complete a creatinine test on a patient
A. Consider reducing the patient dose
If the pitch for a CT study is changed from 1.1 to 1.0, which of the following three changes will occur, assuming all other variables remain unchanged?
A. Increased computed tomography dose (CTDI)
B. Increased dose-linear product (DLP)
C. Decreased patient dose
D. Increased patient dose
E. Decreased image quality
A. Increased computed tomography dose (CTDI)
B. Increased dose-linear product (DLP)
D. Increased patient dose
Increasing the kilovoltage peak (kVp) for a CT procedure results in:
A. Increased attenuation
B. Decreased attenuation
C. No change in attenuation
B. Decreased attenuation
Region of interest (ROI) measurements throughout a single CT image produced the following CT number readings. Which area demonstrates the highest level of attenuation?
ROI 1= -67 HU
ROI 2= -323 HU
ROI 3= +4 HU
ROI 4= +37 HU
ROI 4= +37 HU
Scanning an area of increased tissue density will result in _______ x-ray attenuation.
Increased
The Computed Tomography Dose Index (CTDI) for an adult abdominal scan should not exceed:
A. 25 mGy
B. 85 mGy
C. 40 mGy
D. 75 mGy
A. 25 mGy
The Computed Tomography Dose Index (CTDI) is calculated using:
A. Dose data collected from the patient after the scan.
B. Dose data collected from the cylinder phantoms
C. Dose data collected from the patient during the scan
D. Dose data stored by the American College of Radiology (ACR)
B. Dose data collected from the cylinder phantoms
The computed tomography dose index (CTDI) represents the:
A. Average recorded radiation dose to the phantom
B. Highest recorded radiation dose to the phantom
C. Lowest recorded radiation dose to the phantom
D. Average radiation dose at the center of the phantom
A. Average recorded radiation dose to the phantom
The diameter of the computed tomography dose index (CTDI) body phantom is:
A. 25 cm (10 in)
B. 16 cm (6 in)
C. 32 cm (12 in)
D. 50 cm (20in)
C. 32 cm (12 in)
The energy of ions created in air from x-rays.
Air Kerma
The main purpose of traditional lead shielding is to reduce:
A. Superficial dose in the exposure field
B. Superficial dose outside of the exposure field
C. Scatter radiation absorption in the exposure field
D. Scatter radiation absorption outside of the exposure field
D. Scatter radiation absorption outside of the exposure field
The number of ionization events in air is described as:
Exposure
The patient below is being scanned using the computed tomography angiography (CTA) pulmonary embolism protocol. This shielding technique is unacceptable because the:
A. Patient’s arms are outside of the shield
B. Shield is in the exposure field
C. Patient is not shielded in 360 degrees
D. Patient should not be shielded.
B. Shield is in the exposure field
The patient in the following image is being scanned using the CT head protocol. This shielding technique is unacceptable because the:
A. patient’s arms are on top of the shield
B. Shield is in the exposure field
C. Patient is not shielded in 360 degrees
D. Shield is designed for occupational use only
C. Patient is not shielded in 360 degrees
The patient in the following image is being scanned using the CT renal stone protocol. This shielding technique is unacceptable because the:
A. Patient’s arms are under the shield
B. Shield is the exposure field
C. Patient is shielded in 360 degrees
D. Shield is designed for occupational use only
B. Shield is the exposure field
The purpose of a “dose notification” is to:
A. Make the technologist aware that a high computed tomography dose index (CTDI) has been used.
B. Make the technologist aware that a high computed tomography dose index (CTDI) will be used.
C. Make the technologist aware that the scan length is too long
D. Make technologist aware that a low computed tomography dose index (CTDI) will be used.
B. Make the technologist aware that a high computed tomography dose index (CTDI) will be used.
When performing a CT of the neck, where should bismuth shielding be placed?
A. Over the anterior neck
B. Over the posterior neck
C. Over the gonads
D. Around the entire pelvis.
A. Over the anterior neck
When performing a CT of the neck, where should lead shielding be placed?
A. Over the anterior neck
B. Over the posterior neck
C. Over the anterior pelvis
D. Around the entire pelvis
D. Around the entire pelvis
When performing a CT of the patient’s chest, abdomen, and pelvis, where should lead shielding be placed?
A. Around the chest, abdomen, and pelvis
B. Around the pelvis only
C. Around the gonads only
D. Lead shielding should not be used.
D. Lead shielding should not be used.