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Chapter 9
| Question | Answer |
|---|---|
| What is the annual effective dose limit for whole-body exposure of a radiation worker? | 5 rem (50mSv) per year |
| What is the cumulative effective dose limit for a 28-year-old radiation worker? | 280mSv (28rem) equation-(10 X age) |
| Explain the ALARA concept | Keeping all occupational exposre as little as reasonably achievable. |
| What are three basic principles used for minimizing an individual's exposure to ionizing radiation. | Reduce the amount of time spent in the vicinity of the radiation source while its operating, increase the distance between the radiation source and individual to be protected, interpose a shielding material which will attenuate the radiation from the sour |
| What is the difference between primary and secondary protective barrier? | Primary can be struck by the primary or useful beam exiting the x-ray tube. Secondary can only be struck by scattered and leakage radiation. |
| How can a radiographer minimize radiation exposure to the patient? | beam limitations, technique selection, filtration, grids, gonadal shielding, image receptors, projection, equipment, repead radiographs, and patient exposure estimate |
| What is the equivalent dose limit for the embryo-fetus per month? | .5mSv (.5rem or 50mrem) per month |
| According to NRC regulations, how does a woman declare herself pregnant? | In writing, dated, and it must include the estimated month of conception. |
| These groups have shared in the establishment of radiation protection standards | Advisory groups |
| International commission on radiological protection (ICRP) was formed in what year? What is it? and when was it chartered by congress? | Formed in 1928. It is a committee on radiation protection and measurement formed in 1929. 1964 as National council on radiation protection and measurement |
| What is NCRP and what do they do? | National council on radiation protection and measurement. its a nonprofit organization that collects, analyzes, develops, and disseminates information on: radiation protection, radiation measurements, quantities, and units |
| What is NAS-BEIR? | National academy of sciences Advisory Committee on the Biological Effects of Ionizing Radiation. |
| What is UNSCEAR? | United Nations Scientific Committee on the Effects of Atomic Radiation. |
| What are the 2 Regulatory Agencies in the U.S.? | NRC (U.S. Nuclear Regulatory Commission) and the FDA (U.S. Food and Drug Administration) |
| What are agreement states? and is SC one of them? | When the NRC has entered into agreements with the states to oversee and enforce the regulation. In these agreements it is the state's responsibility to enforce NRC regulations. South Carolina IS and agreement state! |
| What does a regulatory Agency do? | They carry the force of law and can inspect facilities, issue fines, and revoke radiation use authorizations. |
| What are the classifications of biological effects? | Stochastic and deterministic (nonstochastic) |
| What is stochastic effect? | has no threshold. its random in nature (ex. cancer or genetic effects). regardless of the amount of dose some will experience an effect. As dose increases the chance of occurrence increases |
| what is Deterministic effects? | Those of which have a threshold. Once threshold is surpassed an increase in dose will increase the severity of response. ex. cataracts, skin erythema and sterility |
| these individuals have a significant potential for exposure to radiation in the course of their employment. | Occupationally exposed worker. |
| Individuals whose duties may occasionally bring them into areas where radiation exposure may occur. | Occasionally exposed workers. |
| individuals who incur as an occupational risk, a certain likelihood of exposure to ionizing radiation in the course of their normal duties. | Radiation workers |
| What is the dose limit for the general public for both frequent and infrequent exposures (continuous) annually | Frequent- .1 rem (1 mSv). Infrequent .5 rem (5mSv) |
| What is the NRC? | Nulcear Regulatory Commission which is a federal agency where regulations are laws and are recorded in Federal register |
| What are the principles of personnel exposure reduction? (3 cardinal rules) | Time, Distance, Shielding |
| What are structural protective barriers? | Materials having effective x-ray attenuating properties and of thicknesses sufficient to reduce exposures to the desired levels. commonly used materials include lead sheet, concrete, lead glass, steel and leaded acrylic. |
| What are the two classifications of protective barriers? | Primary and secondary barriers. |
| What is a primary barrier? | Are struck by the primary or useful beam exiting the x-ray tube. |
| What is a secondary barrier? | Can only be struck by scattered or leakage radiation. (always thinner than primary barriers) The primary beam cant be directed at the secondary barrier |
| When are protective devices used, name some types, and what is the thickness of lead in them? | Protective devices are used when it is not possible to remain behind a barrier. ex. lead aprons, lead gloves, lead glasses, and thyroid shields. they range from .25-1.0 mm lead equivalent |
| Name some ways to protect the patient. | Beam limitations, technique selection (high kVp/low mAs decrease pt. dose), Filtration, Grids, Gonadal shielding, image receptors, projection, repead radiographs (try not to), patient exposure estimates, and equipment |
| What does filtration do? | removes low energy photons |
| What is the thickness required for filters? | 2.5 mm Al/eq filtration required when operating at or above 70 kVp |
| What happens when you increase filtration? | Technique increases. pt. dose is still reduced with greater filtration |
| What should you do when using grids? | use lowest possible grid ratio to effectively remove scatter |
| What is the most important thing to remember when decideing to shield the gonadal area? and what are the types of gonadal shields? | Gonadal shielding should be used any time th gonads lie within 5 cm of the primary beam. Flat contact, shaped contact, and shadow shields. |
| When is the fetus of a pregnant woman particularly radiosensitive? | From 8-15 weeks of gestation |
| What is the monthly equivalent dose limit for a fetus? | .05 rem |
| When is the risk of malformation significant? | 15 rad |
| What is the dose equivalent for a pregnant radiation worker? | .5 rem for entire pregnancy |
| What is the fetal equivalent dose limit for a fetus of a pregnant radiation worker? | .05 rem per month |
| When you have a pregnant patient what is the current recommendation? | Reschedule x-ray. The ordering physician must consider patient's entire clinical status, including possibility of pregnancy |
| Radiation exposure limits pertinent to the protection of radiation workers are known as what? | Dose limits |
| These are subdivided into what two groups? | Whole body and certain tissues and organs |
Created by:
MissPiggy