V3 - Safety Flashcards
What is the primary purpose of beam filtration?
Protect patient from low energy x-rays
Place the following actions in order of greatest to least impact for reducing occupational exposure during fluoro.
Stand behind the control panel > Double distance from x-ray source or patient > Cut exposure time in half > Wear a led apron
A 6yo pediatric patient arrives in radiology suite for a radiograph of the abdomen. Which set of technical factors provides the best radiation protection?
82 kVp, 7.5 mAs
Which is the primary controlling factor for x-ray beam quality?
kVp
Which fluoroscopic mode results in the lowest patient dose?
Digital pulsed progressive
Which are by-products of photoelectric absorption?
Photoelectron and characteristic photon
When a pregnant patient must undergo a radiographic procedure, which practices will minimize radiation exposure? (3)
- Select appropriate exposure factors for the parts being imaged.
- Shield the abdomen and pelvis whenever this does not interfere with the image.
- Collimate to include only the area of interest.
Which statement correctly describes the amount of kinetic energy required for a photon to remove an inner shell electron from its orbit?
The same as or greater than the electron binding energy.
Which term means the loss or change of a nitrogenous base in the DNA chain?
Mutation
Which describes the relationship between linear energy transfer (LET) and relative biologic effectiveness (RBE)?
As LET increases, RBE increases
What is the advantage of using a high kVp, and low mAs technique with DR systems?
Patient exposure decreases
For which purpose is gonadal shielding recommended?
To reduce the probability of genetic mutations
How will the dose area product (DAP) be affected during a 4 Roentgen exposure if the collimated field is reduced from 8 x 8 cm to 4 x 4 cm?
DAP will be 1/4 of the original
Which human cell is the most resistant to the effects of the radiation?
Neurons
At which energy range does photodisintigration occur?
Above 10 megaelectron volts (MeV)
How should a mobile C-arm fluoroscope be positioned to provide maximum radiation protection to the operator?
With the x-ray tube under the patient and as far from the patient as possible
A radiographer performs an abdomen examination with a mobile DR system. In order to reduce the likelihood of repeat exposure, he decides to increase the technical factors slightly more than necessary. Which term refers to this undesirable practice?
Dose creep
Which combination of technical factors is recommended to reduce patient dose?
High kVp, low mAs
According to FDA, what is the maximum air kerma rate for fixed fluoroscopic units?
10 cGy/min
Which regulatory agency has the authority to control the possession, use, and production of atomic energy in the interest of national security?
Nuclear regulatory commission
Which procedures should imaging personnel perform in order to reduce exposure time during fluoroscopic procedures? (3)
- Use the pulsed progressive mode.
- Use the last image hold feature.
- Reset the cumulative timer before procedure.
Which whole-body dose most closely approximates the LD 50/30 for humans?
3 Sv
A radiographer stands 6 feet from the x-ray source when performing a portable chest exam and receives an exposure of 2 mGy. If the radiographer performs a repeat exam using the same technical factors standing at a distance of 3 feet from the course, how much exposure will be received?
8 mGy
Place the following types of dosimeters in proper order from least radiosensitive to most radiosensitive.
Film badge > TLD > OSL > Pocket ionization chamber
How many millimeters of lead equivalency is recommended for lead aprons worn by pregnant radiographers?
0.5mm
Which type of radiation is produced when an outer shell electron fills an inner shell vacancy?
Characteristic
Over the entire gestational period, what is the fetal exposure limit?
5 mSv
Which interaction with matter contributes to the majority of occupational exposure?
Compton scattering
With all other factors remaining the same, a decrease in kVp will cause an increase in which x-ray beam characteristic?
Wavelength
Biologic damage resulting from the ionization of key atoms causing these molecules to become inactive or functionally altered is much more likely to occur after exposure to which type of radiation?
High LET radiation such as alpha particles
For which lumbar spine projections should a shaped contact shield be applied to provide protection for the gonads of a male patient? (3)
- AP.
- L5-S1 spot.
- AP RPO.
What is the minimum recommended filtration for general diagnostic x-ray units?
2.5mm Al
Which term refers to the removal of an electron from the orbital shell of an atom?
Ionization
Which is the maximum allowable exposure to the embryo or fetus each month?
0.5 mSv
Which organ has the highest tissue weighting factor?
Gonads
Which minimum thickness of lead shielding is required to cover the bucky slot during fluoroscopic exams?
0.25mm
Which is the required amount of inherent filtration for general purpose x-ray tubes?
0.5mm aluminum (AL) equivalent
In the diagnostic energy range, which substances possess the greatest ability to absorb radiant energy through the process of photoelectric absorption?
Bone
In which position should the patient be placed in order to demonstrate the right intervertebral foramina of the cervical spine while minimizing radiation dose to the thyroid gland?
RAO
What is the maximum allowable tabletop intensity in high-level control (HLC) fluoroscopic procedures?
200 mGya/min
If all the other factors remain constant, how is radiation dose related to SOD?
By the Inverse square law
Which dose may cause temporary sterility of both males and females?
2 Gy
What is the annual occupational effective dose limit for a non-pregnant radiation worker?
50 mSv
Which is the most likely result if an exposure is made without the use of a focusing cup?
Increased off focus radiation
Which method should be the first choice to reduce exposure to reproductive organs in every radiographic exam?
Collimate to include only the anatomy of interest
Which factors will impact the radiation barrier calculations for an x-ray room? (3)
- How often the room is used.
- Types of exams performed in the room.
- People in the adjoining room.
Which term is used to describe the intensity of the x-ray beam?
Quantity
A 14yo female patient arrives in the radiology department for a scoliosis series. Which option provides both the best image quality and lowest radiation dose for this patient?
Employ shadow shields
Which type of interaction results in the production of bremsstrahlung x-rays?
A projectile electron slows down near the nucleus of the target atom.
Which value represents the annual maximum dose limit (in mSv) for exposure to the extremities in medical imaging personnel?
500 mSv
Which describes a linear, non-threshold dose response relationship?
No dose may be considered completely safe.
How is the process of thermionic emission described?
Electrons are released when the filament is heated
Which term is an alternate name for the prodromal stage of acute radiation syndrome (ARS)?
Initial stage
