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RADT465 Safety
ARRT registry review covering safety content area
| Question | Answer |
|---|---|
| What does the term wavelength mean? | the distance from one crest to the next crest ( 8) |
| What does the term frequency mean? | the number of waves in a given period of time (8) |
| How are frequency and wavelength related? | Inversely ; the higher the frequency, the shorter the wavelength (8) |
| How much of the primary beam is Bremsstrahlung radiation? | 70-90% (8) |
| How much of the primary beam is Characteristic radiation? | 10-30% (8) |
| Explain Bremsstrahlung radiation | An electron (-) accelerates towards the nucleus of an atom (+) and is deflected, causing a loss of energy ; creates polyenergetic beam (8) |
| Explain Characteristic radiation | An electron accelerates towards an atom and ejects K-shell electron. The K-shell vacancy is filled by a higher energy level electron. The difference in the energy creates a K-shell characteristic photon; Always have 69 keV energy (8) |
| What is the definition of attenuation? | ionizing radiation passing through tissues and slowing down (8) |
| What does the photoelectric effect contribute to? | Patient dose with characteristic x-ray photons (8) |
| What does Compton scattering contribute to? | Occupational dose; mostly coming from the patient (8) |
| What are some examples of effects based on a a linear, nonthreshold dose response curve? | radiation-induced leukemia, cancer, and genetic effects , late effects(8) |
| What type of dose response curve do x-rays follow? | Linear nonthreshold; there is no "safe" dose (8) |
| What are stochastic effects? | "all or nothing" ; they are not determined by levels of severity (8) ; follows the linear nonthreshold dose response curve |
| What is another name for stochastic effects? | probabilistic (8) |
| What are some examples of effects based on a nonlinear threshold dose response curve? | Skin erythema, early effects (8) |
| What is another name for nonstochastic effects? | deterministic or predictable (8) |
| What is the Law of Bergonie and Tribondeau? | Highly radiosensitive cells are those that are undifferentiated (stem cells), young & immature, and highly mitotic cells (reproductive cells) Ex.) intestinal epithelial cells (8) |
| What is the definition of LET? | Linear Energy Transfer; the rate at which energy is deposited by radiation as it passes through tissue (8) |
| What can specifically occur during the 2nd and 10th weeks of pregnancy if certain radiation levels are met? | Fetal anomalies (8) |
| What types of genetic effects can occur during the first trimester of pregnancy if a specific radiation level is met? | Fetal anomalies, skeletal/organ anomalies, neurologic anomalies, childhood malignant diseases, slowed growth/lack of development (8) |
| What level of fetal irradiation can cause embryonic resorption or spontaneous abortion in the first 2 weeks of pregnancy? | 250 mGy (.25 Gy) (8) |
| What is the genetically significant dose? | average annual gonadal dose to the childbearing population ; 0.2 mSv (8) |
| What are somatic effects? | effects that affect the body itself (8) ; can be early or late |
| What are some examples of late somatic effects? | Ca, cataractogenesis, life-span shortening (8) |
| What level of ionizing radiation does Hematopoietic syndrome of ARS occur? | at least 0.5-1.0 Gy (8) |
| What level of ionizing radiation does Gastrointestinal syndrome of ARS occur? | 10-100 Gy (8) |
| What level of ionizing radiation does CNS syndrome of ARS occur? | >50 Gy (8) |
| What are the four stages of ARS? | Prodromal, Latent, Manifest illness, and Recovery/Death (8) |
| What is the most important consideration in reducing patient exposure? | patient communication (9) |
| What are the three types of beam restrictors? | aperture diaphragms, cones, and collimators (9) |
| What should the accuracy of the collimators be when doing QC testing? | 2% of the SID (9) |
| What types of generators are predominantly used in radiography? | 3-phase & high frequency because nearly constant potential waveform and reduced patient dose (9) |
| If operating equipment using less than 50kV, how much filtration is required? | 0.5 mm Al (9) |
| If operating equipment using 50-70 kV, how much filtration is required? | 1.5 mm Al (9) |
| If operating equipment using above 70kV, how much filtration is required? | 2.5 mm Al (9) |
| What is the total filtration requirement? | 2.5 mm Al equivalent (9) |
| How close to the FOV do the gonads have to lie to use shielding? | 5 cm (9) |
| What are the two types of AECs? | Ionization chambers and phototimers (9) |
| What is the minimum response time? | the shortest exposure time that can be used with a particular AEC (9) |
| What is the definition of linearity? | Same exposure rate across adjacent mA stations (9) |
| What is the definition of reproducability? | Every time a specific technique is used, it should produce the same exposure rate (9) |
| How does the ESE compare to the exit dose> | ESE is significantly higher (9) |
| What is the QC rule for reproducability? | must not exceed 5% variation (9) |
| What is the QC rule for linearity? | must not exceed 10& variation (9) |
| How can single-phase equipment's timer be tested vs. three-phase equipment? | simple spinning top vs. synchronous spinning top (oscilloscope) (9) |
| What type of switch must the exposure switch be? | Dead-man's switch (9) |
| NCRP recommends personal monitoring to workers receiving what dose? | 5mSv/year ; 10% of the occupational dose limit) (10) |
| What is the annual occupational dose limit? | 50mSv/year (10) |
| What is the cumulative dose for an individual? | 10 mSv X age |
| What is the intensity of scatter radiation 1m from the patient? | 1/1000th of the intensity of primary beam (10) |
| Leakage radiation from tubes may not exceed what level? | 1 mGya/hr when measured at 1m from the tube (10) |
| How much lead should the image intensifier have? | 2.0 mm Pb (10) |
| How much lead should the Bucky slot cover have? | 0.25 mm Pb (10) |
| How much lead should the screen drape and tableside shield have? | 0.25 mm Pb (10) |
| How much lead should aprons have? | Must be at least 0.25 mm Pb, but the NCRP recommends 0.5 mm Pb (10) |
| How much lead should gloves have? | 0.25 mm Pb (10) |
| Where is the greatest amount of occupational exposure received? | Fluoroscopy and mobile radiography (10) |
| What is a controlled area? | Area accompanying radiology personnel and patients (10) ; receiving less than 1mSv per week |
| What do primary protective barriers consist of? | 1/16th inch (1.5mm) lead thickness and 7 ft height ; any area struck by useful beam (10) |
| What do secondary protective barriers consist of? | 1/32th inch (0.75 mm) lead thickness and above 7 feet height; control booth (10) |
| Uncontrolled area exposure should be limited to ...? | 21 mSv/ year (10) |
| What factors determine the thickness of primary barriers? | occupancy factor, workload, and use factor (10) |
| Fluoro equipment must provide _______ between the tabletop and x-ray source? | 30 cm (12 in) (10) |
| What are the SI units? | Gray, Sieverts, and Air Kerma (11) |
| What are the 5 types of personal radiation monitors? | OSL, TLD, film badge, pocket dosimeter, and ion storage device (11) |
| What is the NCRPs recommended occupational dose limit for students younger than 18 ? | 1 mSv (11) |
| What is the NCRPs recommended occupational dose limit for the skin, hands, and feet? | 500 mSv (11) |
| What is the NCRPs recommended occupational dose limit for the lens of the eyes? | 150 mSv (11) |
| What is the NCRPs recommended occupational dose limit for the embryo/fetus? | 0.5 mSv (monthly) and 5.0 mSv for entire gestation (11) |
| What are OSL dosimeters and how are they read? | Optically stimulated luminescence; contain aluminum oxide that absorbs and stores the energy from the radiation; the dosimeter is read with a laser and can be read multiple times and quarterly ; most commonly used (11) |
| What are film badge dosimeters and how are they read? | film package enclosed in special holder; read through open window using various filters; used for 1 month (11) |
| What are TLDs and how are they read? | Thermoluminescent; contains lithium fluoride crystals; LiF is heated and produces a visible light ;can read doses as low as 5mrem (11) |
| What are pocket dosimeters and how are they read? | indicative when working with high exposures or large quantities of radiation for short periods of time; immediate reading by user; air is ionized and causes fiber indicator to register radiation in mR (11) |
| What is the direct ion storage dosimeter and how is it read? | newest type; no send off of dosimeters for readings, gas filled ionization chamber that uses bluetooth to relay info via phone or computer technology ; can be read and reread (11) |
| Reference (8) | Saia, D.A. (2018). Radiation Physics and Radiobiology. In S. Barnes, C. M. Thomas (Eds.), Radiography Prep (9th ed., pp. 237-260).Chicago, IL: McGraw-Hill Education. |
| Reference (9) | Saia, D.A. (2018). Patient Protection. In S. Barnes, C. M. Thomas (Eds.), Radiography Prep (9th ed., pp. 261-280).Chicago, IL: McGraw-Hill Education. |
| Reference (10) | Saia, D.A. (2018). Personnel Protection. In S. Barnes, C. M. Thomas (Eds.), Radiography Prep (9th ed., pp. 281-294).Chicago, IL: McGraw-Hill Education. |
| Reference (11) | Saia, D.A. (2018). Radiation Exposure and Monitoring. In S. Barnes, C. M. Thomas (Eds.), Radiography Prep (9th ed., pp. 295-308).Chicago, IL: McGraw-Hill Education. |
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Mrlynn
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