final ch. 10 & 11 Flashcards
Which of the following terms involves a random effect of ionizing radiation?
Stochastic event
The responsibility for maintaining radiation monitoring records for all personnel and for providing counseling for individuals who receive monitor readings in excess of allowable limits belongs to the
designated radiation safety officer of a health care facility.
Which of the following is not an x-ray beam limitation device?
Filter
The protective tube housing serves as a shield against _____________________ entering the x-ray tube, thereby preventing electric shock while also facilitating cooling of the x-ray tube.
the high voltage
When using digital fluoroscopy systems, making use of the last image hold feature can
be an effective dose reduction technique
Which of the following agencies is responsible for enforcing radiation safety standards? ICRP NRC NCRP UNSCEAR
NRC
Determine the cumulative effective dose (CumEfD) to the whole body of an occupationally exposed person who is 27 years old.
270 mSv
Biologic effects such as cataracts that result from exposure to ionizing radiation appear to have which of the following?
Sigmoid threshold dose–response curve
For radiation workers, such as medical imaging personnel, occupational risk may be equated with occupational risk in which of the following?
A. Other industries that are generally considered reasonably safe
B. Somewhat hazardous industries
C. hazardous industries
D. extremely hazardous industries
Other industries that are generally considered reasonably safe
Revised estimates derived from more recent reevaluations of dosimetric studies on the atomic bomb survivors of Hiroshima and Nagasaki indicate which of the following?
An increase in the number of solid tumors in the survivor population
When exposed to radiation as part of their educational experience, 18-year-old students should not exceed an effective dose limit of _________ annually.
1 mSv
Which of the following groups has provided sufficient evidence of the induction of stochastic effects in humans resulting from high radiation absorbed doses?
Japanese atomic bomb survivors
- Responsibilities of a medical facility’s radiation safety officer (RSO) include which of the following?
- Developing an appropriate radiation safety program
- Maintaining radiation-monitoring records for all personnel
- Repairing all broken or defective imaging equipment
1 and 2 only
1. Developing an appropriate radiation safety program
- Maintaining radiation-monitoring records for all personnel
To reduce exposure for pregnant imaging professionals and to control the exposure of the unborn during potentially sensitive periods of gestation, the NCRP now recommends a monthly equivalent dose limit not exceeding ______ per month to the embryo-fetus and a limit during the entire pregnancy not to exceed ________ after declaration of a pregnancy.
0.5 mSv, 5.0 mSv
Which of the following is the annual occupational effective dose that applies to radiographers during routine operations?
50 mSv
The radiographic beam should be collimated so that it is which of the following?
No larger than the image receptor
Both alignment and length and width dimensions of the radiographic and light beams must correspond to within:
2% of the SID
What is the function of a filter in diagnostic radiology?
To decrease the x-radiation dose to the patient’s skin and superficial tissue
HVL may be defined as the thickness of a designated absorber required to do which of the following?
Decrease the intensity of the primary beam by 50% of its initial value
The photostimulable phosphor in the computed radiography imaging plate is more sensitive to scatter radiation before and after it is sensitized through exposure to a radiographic beam. Because of this increased sensitivity, which of the following is true?
- Five millimeters of added aluminum equivalent filtration must always be used during routine CR imaging.
- A radiographic grid may be used more frequently during CR imaging.
- Any source-to-image receptor distance can be used during CR imaging without adjustment in technical exposure factors.
2 only
2. A radiographic grid may be used more frequently during CR imaging.
To minimize skin exposure to electrons produced by photon interaction with the collimator, how far below the collimator should the patient’s skin surface be?
At least 15 cm below
Which of the following aluminum equivalents for total permanent filtration meets the minimum requirement for mobile diagnostic and fluoroscopic equipment?
2.5 mm aluminum equivalent
The trough, or bilateral wedge, filter, which is used in some dedicated chest radiographic units, is an example of which of the following?
Compensating filter
To decrease patient exposure during fluoroscopic procedures, the fluoroscopist can:
- Limit the size of the fluoroscopic field to include only the area of anatomy that is of clinical interest
- Employ the practice of pulsed fluoroscopy to reduce the overall length of exposure
- Choose to use a conventional fluoroscope instead of an image intensification fluoroscope
1 and 2 only
1. Limit the size of the fluoroscopic field to include only the area of anatomy that is of clinical interest
- Employ the practice of pulsed fluoroscopy to reduce the overall length of exposure
A diagnostic-type protective tube housing must be constructed so that leakage radiation measured at a distance of 1 m from the x-ray source does not exceed ______ when the tube is operated at its highest voltage at the highest current that allows continuous operation.
1 Gya/hr
