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Monitor and equip
chap 4 and 10
| Question | Answer |
|---|---|
| in keeping with the ALARA concept, most health care facilities issue personnel might receive about _____of the annual occupation EfD limit in any 1 month, or approximately 0.5mSv or 50mrem | 1% |
| a simple detection system of a radiation survey instrument will do what | indicates only the presence or absence of radiation |
| diagnostic imaging personnel should wear a personnel dosimeter during routine operations in an imaging facility because the device provides | indication of working conditions and individual working habits |
| what do the image densities cast by the filters in a film badge permit? | estimation of the energy of the radiation reaching the badge |
| what personnel dosimeter allows a radiation worker to determine occupational exposure received as soon as a specific radiologic procedure is completed? | pocket dosimeter |
| What instrument should be used in a laboratory to detect alpha and beta radiation and small amounts of other types of low-level radioactive contamination? | proportional counter |
| What device is used to measure the visible light emitted bt the sensing material contained in the TLD after exposure to ionizing radiation and heating? | personnel monitoring report |
| When the negatively and positively charged electrodes in the pocket ionization chamber are exposed to ionizing radiation, what does the mechanism do? | it discharges in direct proportion to the amount of radiation to which has been exposed |
| What is a densitometer is used to measure? | optical density |
| What do radiation survey instruments measure? | total qty of electrical charge resulting from ionization of the gas and rate at which an electrical charge is produced |
| What do ionization chamber-type survey meters, proportional counters, and GM detectors have in common? | all contain a gas-filled chamber |
| Which radiation monitor is most commonly used for monitoring occupational exposure in diagnostic imaging? | OSL (optically stimulated luminescence dosimeter) |
| What are some disadvantages of using a TLD as a personnel monitoring device? | it can only be read once because the read out process destroys the stored information, it is necessary to use calibrated dosimeters with TLD’s, the initial cost is higher than that for a film badge |
| Before a pocket dosimeter is used to record radiation exposure, the quartz fiber indicator of the transparent reading scale should indicate a reading of ? | zero |
| The OSL dosimeter uses what kind of detector? | Al2O3 |
| A pocket ionization chamber resembles? | an ordinary fountain pen |
| Where should the control badge sent from monitoring companies with each batch of dosimeters badges be kept? | in a radiation-free area |
| Dosimeter badge readings that exceed a trigger level set by the health care facility are investigated to? | ascertain the cause of the reading |
| What does the TLD readout process do to the information stored in TLD? | destroys it |
| An ionization chamber-type survey meter is also referred to as a? | Cutie pie |
| The increased sensitivity of the OSL dosimeter makes it ideal for monitoring employees working in low-radiation environments and for? | monitoring of pregnant workers |
| The RSO in a health care facility receives and reviews personnel monitoring reports to? | assess compliance with ALARA guidelines |
| Wearing a personnel dosimeter in a consistent location is the responsibility of the? | individual wearing the device |
| On termination of employment a radiographer should receive a copy of? | occupational exposure report |
| What two devices are used for personnel monitoring? | OSL (optically stimulated luminescence dosimeter)and TLD (thermoluminescent dosimeter) |
| When the laser light is incident on the sensing material in an OSL dosimeter the material becomes? | luminescent in proportion to the amount of radiation exposure received |
| What chemical functions as the sensing material in a thermoluminescent dosimeter? | lithium fluoride |
| During routine radiographic procedures when a protective apron is not being worn the primary personnel dosimeter should be attached to the clothing on the front of the body at? | collar level to approximate the maximum radiation dose to the thyroid and the head and neck |
| What are the requirements radiation survey instruments should fill? | reliable to accurately record exposure or exposure rate, durable to withstand normal use, interact with ionizing radiation in a manner similar to the way in which human tissue interacts |
| During diagnostic imaging procedures how should the radiation dose to the abdomen of a pregnant tech be monitored during gestation? | obtained from a second radiation monitor worn at abdominal level |
| When hands of a radiation worker are near the primary beam, the equivalent dose to the hands may be determined through the use of? | TLD ring badge worn on the hand |
| What instrument is used to calibrate radiographic and fluoroscopic x-ray equipment? | ionization chamber with electrometer |
| For x-ray and gamma ray photons with energies from 5KeV to excess Mev what dosimeter gives and accurate reading as low as 1mrem? | OSL (optically stimulated luminescence dosimeter) |
| What instrument should be used to locate a lost radioactive source or detect low-level radioactive contamination? | GM detector (Geiger Mueller) |
| What instrument should be used in an x-ray installation to assess fluoroscopic scatter radiation exposure rate? | ionization chamber with electrometer |
| 1. The beam should be collimated so that it is what? | No larger that the IR |
| 2. Both alignment, length, and width dimensions of the light beam must be within: | 2% of the SID |
| 3. What is the function of a filter in diagnostic radiology? | To decrease the x-radiation dose to the pt’s skin and superficial tissue |
| 4. HVL may be defined as the thickness of a designated absorber required to do what? | Decrease the intensity of the primary beam by 50% of its initial value |
| 5. Because of the increased sensitivity to scatter of the photostimulable phosphor in CR imaging plate, which is true? | A radiographic grid may be used more frequently during CR imaging |
| 6. To minimize skin exposure to electrons produced by photon interaction with the collimator, how far below the collimator should the pt’s skin surface be? | Atleast 15 cm below |
| 7. Which of the following aluminum equivalents for total permanent filtration meets the minimum requirement for mobile diagnostic and flouro equipment? | 2.5 mm aluminum equivalent |
| 8. The trough or bilateral wedge filter which is used in some dedicated chest x-ray units is an example of which of the following? | Compensating filter |
| 9. To decrease pt exposure during flouro, the flouroscopist can: | limit the size of the field to include only area of interest and employ the practice of pulsed flouro to reduce length of exposure |
| 10. 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. | 100 mR/hr (2.58 x 10^-5 C/kg per hour) |
| 1. To meet radiation safety features, radiographic equipment must have: | correctly functioning control panel, protective tube housing, radiographic examination table designed to reduce pt radiation dose |
| 2. There are various types of digital radiography image receptors. Some use a scintillator such as amorphous silicon, to: | Convert x-ray energy into visible light |
| 3. The luminance of the collimator light source must be: | Adequate to permit the localizing light beam to outline the margins of the radiographic beam adequately on the pts anatomy |
| 4. Which of the following results in an increase in the pt dose? | Use of a radiographic grid |
| 5. The pt dose decreases and the life of the flouro tube increases with which of the following? | Intermittent, or pulsed, flouro |
| 6. When fluoroscopic field size is limited to include only the area of clinical interest by adequately collimating the x-ray beam, pt area or integral dose: | decreases substantially |
| 7. Digital radiography eliminates the need for almost all retakes resulting from improper technique selection because the image: | Contrast and overall brightness can be manipulated after image acquistion |
| 8. Computed radiography involve: | Use of conventional radiographic equipment, selection and use of standard technical exposure factors, and traditional pt positioning performed by a radiographer |
| 9. Which of the following is the most versatile for defining the size and shape of the radiographic beam? | Light-localizing variable-aperture rectangular collimator |
| 10. The use of digital radiographic systems offers a number of advantages over both CR and conventional film-screen systems. Some of these include: | immediate imaging results and lower dose |
| 11. In CR imaging, when a grid is required to radiograph anatomy sections over 10 cm in thickness or for techniques that exceed 70 kVP, pt dose received is: | Significantly higher than is delivered with film-screen imaging because the mAs required is significantly higher |
| 12. Flouro equipment equipped with high-level control(HCL) may permit a skin entrance exposure rate as great as which of the following? | 20 R/min |
| 13. To protect the pts skin form exposure to electrons produced by photon interaction with the collimator, the skin surface should at least_____ below the collimator. | 15 cm |
| 14. To reduce pt entrance dose during C-arm flouro procedures, the patient-image intensifier distance should be: | As short as possible |
| 15. Which of the following may reduce pt exposure to off-focus radiation? | placing the first pair pf shutters in the collimator as close as possible to the x-ray tube window |
| 16. Which of the following is an effective technique for reducing pt dose when a digital flouro system is used? | Using the last-image-hold feature |
| 17. Compared with pts who undergo cineflouro procedures that use lower frame rates, pts who undergo more rapid dynamic function studies (eg heart catherterization) receive: | Higher radiation doses |
| 18. HLCF is an operating mode for state-of-the-art flouro equipment in which exposure rates are: | Substantially higher than those normally allowed in routine flouro procedures |
| 19. Monitoring and documentation of procedural flouro time is essential to good practice. The responsibility for monitoring and documentation generally belongs to: | the radiographer assisting with the procedure |
| 20. HVL is expressed in: | Milimeters of aluminum |
| 21. Dose reduction and uniform imaging of the body parts tat vary considerably in thickness or tissue composition may be accomplished by use of: | Compensating filters constructed of aluminum, lead-acrylic, or other suitable material |
| 22. Resolution of a digital image is sharper when pixels are: | Smaller |
| 23. For certain radiographic examinations the use of asymmetric fil emulsion and intensifying screen combinations result in a recorded image with: | Greater uniformity and a decrease in pt exposure |
| 24. Compared with the resolution of an optimal quality image produced on radiographic film, the resolution of a digital image is: | actually somewhat less |
| 25. Some of the reasons for high exposures during interventional procedures include: | the flouro tube operated for long periods of time in continuous and not pulsed mode, not using the protective curtain or shields on the image intensifier as a means of protection, and extensive use of cine as a recording medium |
Created by:
StudyGroup