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RAD 205: Review
HESI VS3: Safety
| Question | Answer |
|---|---|
| Over the entire gestational period, what is the fetal exposure limit? | 5 mSv |
| The energy range photodisintegration occurs at is ___. | above 10 MeV |
| Which whole-body dose most closely approximates the LD 50/30 for humans? | 3 Sievert |
| 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 |
| The removal of an electron from the orbital shell of an atom is: | ionization |
| Practices which will minimize radiation exposure when a pregnant patient must undergo a radiographic procedure include: | 1. select appropriate exposure factors for the part being imaged 2. Collimate only to area of interest 3. Shield the abdomen and pelvis when this does not interfere with image |
| Which combination of technical factors is recommended to reduce patient dose? | high kVp, low mAs |
| Which interaction with matter contributes to the majority of occupational exposure? | Compton scattering |
| How many millimeters of lead equivalency is recommended for lead aprons worn by pregnant radiographers? | 0.5mm of lead equivalent |
| Which factors provide the best radiation protection for a young pediatric patient? | 82 kVp, 7.5 mAs (high kVp, low mAs) |
| Biologic damage resulting from ionization of key atoms causing these molecules to become inactive or functionally altered is much likely to occur after exposure to which type of radiation? | High-LET radiation such as alpha particles |
| What is the advantage of using high kVp, low mAs technique with digital radiography (DR) systems? | Patient exposure decreases |
| Imaging personnel should perform these three things to reduce exposure time during fluoroscopic procedures: | 1. use the last image hold feature 2. Use the pulsed progressive mode 3. Reset the cumulative timer before procedure |
| What is an alternate name for the prodromal stage of acute radiation syndrome (ARS)? | initial stage |
| Which human cell is the most resistant to the effects of radiation? | neurons (have low metabolic and reproduction rate) |
| Which are byproducts of photoelectric absorption? | photoelectron and characteristic photon |
| What is the primary controlling factor for x-ray beam quality? | kilovolt peak (kVp) |
| Which describes linear, non-threshold dose-response relationship? | no dose may be considered completely safe |
| Which fluoroscopic mode results in the lowest patient dose? | digital pulsed progressive |
| which is the most likely result if an exposure is made without the use of a focusing cup? | increased off-focus radiation |
| What is the maximum allowable tabletop intensity in high-level control (HLC) fluoroscopic procedures? | 200 mGya/min |
| What is the maximum allowable millisievert exposure to the embryo or fetus each month? | 0.5 mSv |
| A radiographer stands 6 ft 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 at a distance of 3 ft from the source, how much exposure will be received? | 8 mGy inverse square law; original intensity/new intensity = (new distance/original distance)^2 |
| Which method should be the first choice to reduce exposure to the reproductive organs in every radiographic exam? | Collimate to include only the anatomy of interest |
| Which value represents the annual maximum dose limit for exposure to the extremities in medical imaging personnel? | 500 mSv |
| Which option provides both the best image quality and lowest radiation dose for a 14 y.o. female patient for a scoliosis series? | employ shadow shields |
| How will the dose area product (DAP) be affected during a 4 roentgen exposure if the collimated field is reduced from 8x8cm to 4x4cm? | DAP will be 1/4 of the original |
| 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 term means the loss or change of a nitrogenous base in the DNA chain? | Mutation |
| Which type of radiation is produced when an outer-shell electron fills an inner-shell vacancy? | Characteristic |
| 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 |
| What term is used to describe the intensity of the x-ray beam? | Quantity |
| Place in order of least to most radiosensitive: Pocket ionization chamber, Thermoluminescent dosimeter (TLD), film badge, Optically stimulated luminescent dosimeter (OSL) | 1. Film badge 2. TLD 3. OSL 4. Pocket ionization chamber |
| Place in order of greatest to least impact for reducing occupational exposure during fluoro: Wear a lead apron, stand behind control panel, double distance from x-ray source or patient, cut exposure time in half | 1. stand behind control panel 2. Double distance from x-ray source or patient 3. cut exposure time in half 4. wear a lead apron |
| 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 |
| What term describes an undesirable practice when the technologist increases the technical factors slightly more than necessary to reduce likelihood of a repeat exposure? | dose creep |
| What is the minimum thickness of lead shielding required to cover the bucky slot during fluoroscopic exams? | 0.25mm |
| What is the primary purpose of beam filtration? | protect patient from low energy x-rays |
| What 3 factors will impact the radiation barrier calculations for an x-ray room? | 1. people in adjoining rooms 2. types of exams performed in the room 3. how often the room is used |
| If all other factors remain constant, how is radiation dose related to source-to-object distance (SOD)? | by the Inverse Square Law |
| What is the purpose of gonadal shielding? | to reduce the probability of genetic mutations |
| Which dose may cause temporary sterility of both males and females? | 2 Gy |
| 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 |
| With all other factors remaining the same, a decrease in kVp will cause an increase in which x-ray beam characteristic? | wavelength |
| How is the process of thermionic emission described? | electrons are released when the filament is heated |
| According to the FDA, what is the maximum air kerma rate for fixed fluoroscopic units? | 10 cGy/min |
| What is the annual occupational effective dose limit for a non-pregnant radiation worker? | 50 mSv |
| In the diagnostic energy range, which substances possess the greatest ability to absorb radiant energy through the process of photoelectric absorption? | bone |
| Which is the required amount of inherent filtration for general purpose x-ray tubes? | 0.5 mm Al equivalent |
| For which lumbar spine projections should a shaped contact shield be applied to protect the gonads of a male patient? | AP, AP oblique (RPO), and L5-S1 Lateral spot |
| What is the minimum recommended filtration for general diagnostic x-ray units? | 2.5 mm Al |
| Which describes the relationship between linear energy transfer (LET) and relative biologic effectiveness (RBE)? | as LET increases, RBE increases |
| Which organ has the highest tissue weighting factor? | Gonads |
Created by:
Gabipattie