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Unit 4 Flashcards

QuestionAnswer
What is the distance between two consecutive wave crests? Wavelength (pg. 229)
Approximately 79% of manmade radiation exposure in the United States is made from _____________ and ____________. X-rays and nuclear medicine (pg.231)
List four sources of natural background radiation. Radon and thoron gases, space radiation, internal sources, and terrestrial sources (pg. 231)
What is the source of electrons in diagnostic x-ray? Heated cathode filament (pg. 232)
This type of radiation creates about 70-90% of the primary x-ray beam. Bremsstrahlung (pg. 232)
What type of radiation does a relatively low-energy x-ray photon interact with tissue and expends all of its energy to eject an inner shell electron? Photoelectric (pg. 233)
What illustrates the relationship between exposure to ionizing radiation and possible resultant biologic responses? Dose-response curves (pg. 234)
How much radiation does an average chest x-ray emit? .10 mSv or (10 mrem) (pg. 235)
What describes that their is no safe dose and even one photon can cause a response? Nonthreshold (pg.236)
Chromosome aberrations are more likely to occur at ___________ temperatures because repair processes are inhibited. Lower (pg. 241)
How much radiation can result in embryonic resorption or spontaneous abortion during the first 2 weeks of gestation? At least 250 mGy/25 rad (pg. 242)
What sex receives more gonadal radiation exposure? Females (pg. 243)
What is the term when a high dose of radiation delivered to the whole body in a short period of time? Somatic (pg. 245)
What are the four stages of acute radiation syndrome? Prodromal, Latent, Manifest illness, and recovery or death (pg. 246)
What dose leads to Cardiovascular Syndrome where there is a collapse of circulatory system, as increased pressure in the cranial vault, vasculitis, meningitis, ataxia, and shock? 5000 rad (50 Gy) (pg. 246)
What percent of cancers could result from diagnostic radiation? 5% (pg. 253)
What happens when beam is restricted? Reduces patient dose, reduces production of scattered radiation, and improves image quality (pg. 254)
What percent does the NCRP state a single side for SID should be? 3% (pg.256)
Beam filtration results in an x-ray beam to have what? Higher average energy (pg. 257)
What is the purpose of filtration? To reduce patient skin dose (pg. 257)
What is the Aluminum equivalent necessary for equipment operated above 70 kV? 2.5 mm (pg. 258)
List the three items when gonadal shielding should be used? The gonads lie in, or within 5 cm of the collimated field, the patient has reasonable reproductive potential, and if diagnostic objectives permit (pg. 259)
When should breast shields be used? Female patients during scoliosis series (pg. 261)
Ionization chambers and phototimers are two types of what? Automatic Exposure Controls (pg. 264)
Rare earth phosphors are at least ______________ times faster than the earlier calcium tungstate phosphors? Four (pg. 265)
When are 16:1 grid ratio recommended for use? Examinations using 100 kV (pg. 265)
This refers to consistency in exposure output during repeated exposures at a particular setting? Reproducibility (pg. 266)
What is the SSD must be ________ for stationary fluoroscopic equipment? 15 inches (pg. 267)
The quality assurance term used to describe consistency in exposure at adjacent mA station is? Linearity (pg. 270)
What is the limit for occupational dose for technologist for 1 year? 100 mrem/yr (1mSv/yr) (pg.273)
What is the tabletop intensity limit for a fluoroscopic beam? 10 R/min (pg. 275)
What is the most important cardinal rule? Distance (pg. 277)
What is the thickness that lead aprons and secondary radiation barriers must be? .25 mm Pb (pg. 278)
How often should lead aprons and gloves be imaged? Annually (pg. 279)
What mA do most fluoroscopy image-intensified units operate between? 1 and 3 mA (pg. 281)
A pregnant radiographer should wear a special second radiation monitor at waist level _______________ her lead apron? Under (pg. 281)
How high do primary radiation barriers must be? 7 feet (pg. 283)
What is the length the exposure cord must be on a mobile unit? 6 feet from the x-ray tube and patient (pg. 281)
What is the SI unit for rem? Sievert (Sv) (pg. 288)
What describes the radiation absorbed dose? Rad/ Gray (pg. 288)
What measures ionization in air? Roentgen/ Air Kerma (pg. 288)
List the four used personal radiation monitors. Optically stimulated luminescence, thermoluminescent dosimeter, film badge, and pocket dosimeter (pg. 289)
What is the minimum dose OSL dosimeter can read out? 1 mrem (pg. 290)
How long are film badges used for? 1 month (pg. 291)
What does a TLD contain? Crystalline chips of lithium fluoride (pg. 291)
Which dosimeter is more sensitive and precise TLD or film badge? TLD because it can measure doses as low as 5 mrem compared to film badge (pg.292)
When would a pocket dosimeter be used? When working with high exposures or large quantities of radiation for a short period of time (pg. 292-293)
What type of radiation is a radiographer exposed to? Low-energy, low-LET radiation (pg. 293)
What does the NCRP Report No. 116 require occupationally exposed individuals 18 years of age and older not to receive exposures over? 5 rem (50 mSv) /yr (pg. 294)
How do you calculate the lifetime cumulative exposure for the occupationally exposed individual? 1 rem x age in years (pg. 295) {example 23 year old. 1 rem x 23 = 23 rem (230 mSv) (lifetime at the age)
How often are film badges processed? Monthly (pg. 296)
What do OSL, film badges, pocket dosimeters, and TLD measure? Exposures to x, beta, and gamma radiations (pg. 296, 298)
What type of crystals are used in an optically luminescent dosimetry system? Aluminum Oxide (pg. 298)
Created by: bulanowski