Main property of x-radiation that makes it potentially hazardous is its ability to? - ANSWER-Ionize
Describe the damage potential of ionization? -
... [Show More] ANSWER-Chain reaction in the human body that may eventually cause biologic damage. X-rays are from the Electric Magnetic Spectrum or radiation energy and is considered harmful in high energy ranges.
What is the most likely potential hazard working with diagnostic radiology? - ANSWER-Carcinogenesis - Stochastic/Non-Threshold Effect
.1 Rem = ? Seivert - ANSWER-1 Sievert
0.1 Gray = ? Rad - ANSWER-10 Rad
1 Gray = ? Rad - ANSWER-100 Rad
What is Aplastic Anemia? When dose it occur? - ANSWER-All types of blood cells: Red & White
25 Rads
A decrease in blood count is the earliest response seen to dose radiation. It can occur at dosease as low as? - ANSWER-25 Rads or .25 Gray
What is Cataractogenesis? - ANSWER-Process of Cataract Formation
Cataractogenesis occurs after acute or chronic exposures of how many Rads? - ANSWER-200 Rads, 2 Gray
Skin Eyrythemia (Skin Redning) occurs above? - ANSWER-Above 200 Rad, 2 Gray
Temporary Sterility occurs in the adult male at acute doses of how many Rads? - ANSWER-250 Rads, 2.5 Gray
Pregnant radiographer should? (3) - ANSWER-Always practice TDS
Has legal right for re-assignment of duty
Never confuse collar badge with waist badge
Monthly dosimetry reports is based on what? - ANSWER-OCCUPATIONAL exposures only.
Monthly Dosimeter reports does NOT include? - ANSWER-Natural or Background Radiation
What is the recommended monthly dose-equivalent limit for the fetus in the third trimester? - ANSWER-0.5 mSv
.05 Rem
NRCP 116
Radiation workers cumulative dose-equivalent limit is determined by? - ANSWER-Age x 10 mSv
Age x 1 Rem
NCRP 110
What is the Occupational radiation dose equivalent limit for stochastic effects to the whole body? - ANSWER-50 mSv (5 Rem)
When using a C-Arm mobile unit, the intensification tower should be? - ANSWER-As close as possible to the patient to reduce patient dose and unnecessary magnification.
Radiation exposure in air = ? - ANSWER-Roentgens - Ionization in air dose measurement.
Electrical current being generated by a charge created in air thru ionization by x/gamma radiation is called a? - ANSWER-Ion Chamber
The quantity of radiation exposure measured by an ionization chamber would be? - ANSWER-Coulomb/Kilogram
The C/Kg or R is usually the unit measured in? - ANSWER-Air dose
List the 3 measurements that are more appropriate for measuring absorbed doses for radiation or occupational dose? - ANSWER-Gray (1) - Rad (100)
Seivert (1) - Rem (100)
Curie - Bacquerel
What type of changes are used to measure occupational dose? (3) - ANSWER-Scintillation
Biological
Chemical
Example of personnel monitor that measures radiation thru chemical change reaction? - ANSWER-Film Badge - Operate off Gurney-Mott theory.
Explain the Gurney-Mott Theory...? - ANSWER-Describes how an x-ray photon changes silver halide into atomic silver in the film emulsion--a definite chemical change.
How long can a film badge be worn? - ANSWER-No more than a month
Why shouldn't film badges be worn greater than a month? - ANSWER-Extreme sensitivity to environmental conditions.
TLD's operate thru? - ANSWER-Luminescence (NO chemical rx's occur)
Pocket dosimeters can only work for? - ANSWER-1 day and must be reset everyday.
Upper reading limit of 200-300 rads
Pocket dosimeter uses? - ANSWER-Electrical current as a measurement of charge.
The type of personnel monitor that could be worn the longest is the? - ANSWER-OSD
Optical stimulated detector can be worn up to? - ANSWER-3 months and be sensitive to 2 mR
Leakage radiation should NOT exceed how much mR at 1 meter from the scource? - ANSWER-100 mR per hr
0.1 Rad per hr
NCRP 102
According to Bushong, tabletop intensity should NOT exceed what? - ANSWER-2.1 mR per min for each mA operating at 80 kVp.
Under normal modes of operation, fluoroscopic procedures should NOT exceed? - ANSWER-10 Renkens per min.
What does GSD stand for? - ANSWER-Genetic Significant Dose
What is GSD? - ANSWER-Average gonadal dose received by an exposed population. It is used to estimate the genetic impact of medical radiation dose on the entire population.
Beam limiting devices will? (3) - ANSWER-Improve image quality
Reduce patient dose
Reduce scatter radiation
The purpose of reducing added filtration is to reduce radiation dose to? - ANSWER-Patients skin
Recommended amount of filtration in Fluoro? - ANSWER-3 mm Al Equivalent
Disadvantage to having 3 mm Al Equivalent? - ANSWER-Would require an increase in technical factors defeating the purpose of filtration.
What is the usual amount of filtration in Fluoro? - ANSWER-2.5 mm Al Equivalent
What effect does excessive filtration have on xray image? - ANSWER-Reduced contrast
# of grid lines per inch or centimeter defines? - ANSWER-Grid Frequency
For all dedicated chest units whose tube potential routinely exceeds 90 kVp, the minimum recommended grid ratio is? - ANSWER-8:1
Techniques below or at 90 kVp would utilize what grid ratio? - ANSWER-8:1
Techniques above 90 kVp would utilize what grid ratio? - ANSWER-12:1
What is the ratio of a grid whose lead strips are 0.25 mm thick, 1.6 mm high and are seperated by a 0.10 mm alluminum spacer? - ANSWER-16:1 grid
During latent image formation, the concentration of metallic silver in the exposed crystals occurs in the region of the sensitivity specks. This explanation of the formation of the image is reffered to as? - ANSWER-Gurney-Mott theory
What type of interactions cause ionization of irradiated material? - ANSWER-Photoelectric - Changes inner shell electrons
Compton - Affects outer shell electrons
Which of the following xray interactions with matter is primarily responsible for contrast? - ANSWER-Photoelectric effect
Radiation produces at very discrete energies of approx 69 kiloelectron colts (kev) when electrons interact with the K shell of the tungsten target atom is called? - ANSWER-Characteristic Radiation
Pair-Production affects what portion of the cell? - ANSWER-Nucleus. It does NOT cause ionization.
What type of radiation would produce the greatest amount of biological damage in human tissue? - ANSWER-High LET's
What is the active component of the TLD? - ANSWER-Lithium Fluoride
What is used in input phosphors? - ANSWER-Cesium Iodide
What is used in output phosphors? - ANSWER-Zinc Cadmium Sulfide
What must be done to Xray film to make it compatible to rare earth phosphors? - ANSWER-Add light absorbing dye in the x-ray film emulsion
About what percentage of radiographic density is due to light emitted by an intensifying screen phosphor? - ANSWER-95-98%
What occurs when exit radiation interacts with a Photo-Stimulable imaging plate? - ANSWER-Energy Absorption
What is used in scintillation gamma cameras in nuclear medicine/CT? - ANSWER-Sodium Iodide
What color of light emitted by lanthanum oxy-bromide rare earth crystals in the intensifying screen? - ANSWER-Blue
Maximum # of electron that may be found in the L-Shell of an atom? - ANSWER-8
What is the most radiosensitive part of any human cell? - ANSWER-Chromosome
DNA
Nucleus
What is arguably the MOST radiosensitive cell in the human body? - ANSWER-Mature Lymphocyte
Example of Radiosensitive stem cells? - ANSWER-Neuroblasts
Spermatogonia
Human tissue considered to be the most radio-resistant? - ANSWER-Erythrocyte
What is a Erythrocyte? - ANSWER-End cells w/ no nucleus
Like mature nerve cells, are practically immune from radiation and have about a 4 month life span
Example of Deterministic Effect? - ANSWER-Cataracto-genesis
Examples of Deterministic or Non-Stochastic associated with a threshold dose? - ANSWER-Cataracts (2 grey - 200 Rad)
Examples of Stochastic, Non-Deterministic, Non threshold dose? - ANSWER-Leukemia
Thyroid Cancer
Genetic Effects
Whole body doses only need...? - ANSWER-Very low doses for cancer & genetic effects.
What is a cutie pie? - ANSWER-Radiation survey monitor or it can be a hot personnel monitoring device.
Reduction in resolution often seen with the use of higher tube currents in a single focus tube is a phenomenon called? - ANSWER-Blooming
What type of exposure factors provide the least patient exposure? - ANSWER-Lowest kVp and lowest mAs would cause the lowest patient dose.
What film change can be made to reduce the dose to the patient and surrounding radiographer? - ANSWER-Use higher speed screen w/ a comparable change in mAs
Radiographing Lumbar vertebrae of a geriatric patient, what technique change could be made to reduce patient exposure but maintain significant density? - ANSWER-Increase kVp by 15% with a 50% reduction in mAs
What should be considered when using AEC? - ANSWER-Proper selection of ionization chamber(s)
Precise positioning over desired chambers
NOT Proper selection time
If using automatic exposure control (AEC) device to make an exposure, what would be adjusted to ensure proper optical density from pt to pt? - ANSWER-Set Field Detector's (Chambers)
Set Density compensation (+1, +2...)
NOT Set time!
Where should ionization chambers be located if it is to be used as an efficient automatic exposure - ANSWER-Between the patient and the image receptor
Underexposed radiograph produced by AEC device might result from? - ANSWER-Having insufficient backup time set for a very large patient
Appearance of grid lines on radiograph with the table Bucky in use indicates? - ANSWER-Exposure time too short
What would be used by tech to compensate for the caring densities of anatomic structures on a routine PA projection of the chest? - ANSWER-Trough Filter
Using compression band will have what effect during the production of a radiograph? - ANSWER-Reduces scatter radiation
Decreases radiographic contrast
NOT reduces patient motion
What radiographic procedure requires an image demonstrating a long scale of contrast? - ANSWER-Chest
When using AEC w/ DR, selecting the center chamber on a PA radiogragh results in? - ANSWER-Appropriate density in the lungs
As the field size is increased with all other factors remaining constant, the scale of contrast will? - ANSWER-Be lengthened
What could decrease the production of scatter radiation? - ANSWER-Decrease in kVp
Which of following pathological conditions would allow the x-ray beam to easily penetrate the pt? - ANSWER-Rheumatoid arthritis
Which pathologic condition would require increase in technical factors? - ANSWER-Ascites
What is Ascites? - ANSWER-Fluid in the peritoneal cavity
What would affect shape distortion? - ANSWER-Tube Angulation
If a radiograh demonstrates excessive size distortion, which of the following corrections should be made before repeating? - ANSWER-Increase SID
Image noise can be decreased by? - ANSWER-Increasing xray dose
Purpose does a photo-cathode serve? - ANSWER-Converts light photons to electrons
What type of generator would incorporate a DC chopper in order to convert 60 hz AC to pulsed DC? - ANSWER-High frequency
Disadvantage of a flat panel direct capture detector is? - ANSWER-Difficult in mobile imaging
How many heat units are genera [Show Less]