RADIOGRAPHER ONLINE EXAM PRACTICE KIT 16
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The amount of radiation deposited per unit length of tissue travelled by incoming photons is called:
More energy is deposited by particulate forms of radiation than by waveforms of radiation
Cataractogenesis , life span shortening ,embryological effects, and carcinogenesis are examples of:
All are examples of radiation effects on the individual being exposed
Compton interaction:
Choices A is incorrect because photoelectric interaction produces contrast
Rem multiplied by a radiation weighting factor equals:
The correct equation would be rads multiplied by a radiation weighting factor equals rem.
Effective dose limit:
Correct B is incorrect because no level of radiation is considered completely safe.Correct C is incorrect because no such immunity has been proved.Correct B is incorrect because the effective dose limit for the general public is 500 mrem per year
Radiation with a high LET:
High LET radiation is depositing a lot of energy in the tissues, causing much ionization.
Radiation protection is based on which dose response relationship?
It is assumed that for every dose of radiation , a lot of energy in the tissues causing much ionization.
Which of the following states that the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation?
Cells such as epithelial ,ovarian, and sperm cells.
Which of the following causes about 95% of the cellular response to radiation?
Because the cellular cytoplasm is substantially larger than the cellular nucleus, it is more likely to be struck by incoming x-ray photons.Thus most of the cellular response to radiation is indirect.The direct effect results from x-ray photons directly striking the cellular nucleus.
When radiation strikes DNA , which of the following occurs?
Indirect effect occurs when radiation strikes the cytoplasm of the cell.Target theory states that there is a master molecule that governs cellular activities , that is DNA.
The amount of radiation that causes the number of genetic mutations in a population to double is called the:
This is 50 to 250 rads in humans
the units of equivalent dose, activity,in-air exposure and absorbed dose are:
Be sure to review the units of measurement
Medical x-rays are an example of:
This is human produced radiation
The equivalent dose limit for an embryo or fetus is:
This is the same as the general public’s annual limit for infrequent exposure
The photoelectric effect:
choice B and D refer to electrons and brems radiation ,which apply to action inside the x-ray tube;the photoelectric effect is a photon interaction.
The effective dose limit for radiographers:
Be sure to get the amount and unit of measurement correct
The average dose to active bone marrow as an indicator of somatic effects on a population is called:
This is the definiton of mean marrow dose(MMD).It is not called the bone dose.The doubling dose is the amount of radiation that causes the number of mutations ina population to double. the GSD is the genetically significant dose.
A radiation dose that if received by the entire population would cause the same genetic injury as the total of doses received by the members actually being exposed is called:
This describes the GSD is the genetically significant dose(not genetic dose).The doubling dose is the amount of radiation that causes the number of mutations in a population to double. Mean marrow dose is the average dose to active bone marrow as an indicator of somatic effects on population.
A lead apron of at least what thickness should be worn while being exposed to scatter radiation?
Shielding of lead equivalent, not aluminium equivalent , is used to protect from scatter radiation.The requirement for lead apron is atleast 0.25-mm Pb equivalent,it should be 0.5mm mm Pb equivalent,which is what the question asks.There is a difference between shall and should.
Use of thyroid shield of at least what thickness should be used for fluroscopy?
The requirement for a thyroid shields,if used, during fluroscopy is 0.5 -mm lead, not aluminium equivalent.
How thick are primary protective barriers?
Primary protective barriers consists of 1/16 inch lead equivalent, not aluminium equivalent, secondary protective barriers consists of 1/32 inch lead equivalent
Primary protective barriers, if the wall must extend to a height of at least:
Primary protective barriers in the wall must extend to a height of at least 7 feet, because the height is taller than most people.
Secondary protective barriers, if the wall must extend to a height of
Secondary protective barriers extends from where the primary protective barriers ends to the ceiling with a1/2 inch overlap.
The protective curtain hanging from the fluroscopy tower must at least
The protective curtain hanging from the fluroscopy tower must at least 0.25 mm Pb, not AI , equivalent. Be sure to remember all the shielding requirements
The Bucky slot cover must be atleast:
Be sure to remember all the shielding requirements
Filters made of aluminium and copper are placed in the film badge to measure x-ray:
Filters made of aluminium and copper are placed in the film badge to measure x-ray energy striking the film badge. This is a measure of the beam’s quality, not quantity.
Film badges are changed:
A film badge should not be worn longer than 1 month, at which time a film badge report with readings is returned to the institution.
Thermoluminescent dosimeters use what type of energy to indicate dose?
Lithium fluoride crystals, which release energy as visible light when heated , are used to record dose in TLDs.
TLDs are heated and release what type of energy to indicate dose?
TLDs are heated and release visible light energy to indicate dose. This energy is read by photomultiplier tube.
Optically stimulated luminescence (OSL) dosimeters are sensitive to exposure as low as:
Optically stimulated luminescence (OSL) dosimeters are sensitive to exposure as low as 1 mrem, which takes them 5 times as sensitive as TLDs. This feature along with their wide dynamic range, greater accuracy, and long term stabilty, make them ideal for personnel monitoring
The recording material in an OSl dosimeter is
The recording material in an OSl dosimeter is aluminium oxide,which is then scanned by a laser beam.Film badges use film as the recording material;TLDs use lithium fluroide.Silver halide is the active ingredieni in radiographic film emulsion.
The energy stored in an OSl dosimeter is released when the dosimeter is exposed to:
The energy stored in an OSl dosimeter is releasedby exposure to a laser. The energy is then released as visible light.The energy stored in a TLD is released by heat.
OSl dosimeter may be worn for:
OSl dosimeter may be worn for up to a quarter,although in may cases they may be changed monthly.
OSL dosimeter may be scanned and reanalyzed:
One of the key advantages of OSL dosimeter is the capability of reanalysis for confirmation of dose, which is especially important if a dose in a question.
The most commonly used gonadal shield is the:
The flat contact shield, which consists of a piece of lead placed over the gonads, is most commonly used. It may be as simple as alead apron properly placed. The shadow shield which is suspended from the x-ray housing and does not come in contact with patient, when sterile technique is required.A collimator is not considered a gonadal shielding device.
For optimal radiation protection,what speed of exposure technique should be used?
Low mAs reduces the amount of radiation striking the patient. Chossing the optimum kVp for the part being radiographed increases the quality of the x-ray beam. Low kVp, high mAs would result in the opposite
For optimal radiation protection, what type of IR should be used?
The fastest practical speed for the part being radiographed should be used to reduce patient dose. Slow speed increases patient dose.
The minimum source to skin distance for portable radiography is:
Be sure to review the source to – skin distance requirements.
The personal dosimetry report reads in what units of measurement?
The personal dosimetry report usually reads in units of mrem, the unit of equivalent dose and effective dose, which uses a radiation weighting factor to modify the absorbed dose amount to account for greater damage inflicted by some forms of radiation. Rad meaures the absorbed dose.Roentgen measures the amount of in- air radiation.Curies measure the quantity of radioactive material.
How often is filtration adjusted by the radiographer?
Filtration is adjusted by a medical radiation physcist, not by the radiographer. Compensating filtration such as wedge filters are manipulated by the radiographer.
According to NCRP report #160, the effective dose for a typical CT examination is:
The current alternatives 120 times per second
According to NCRP report #160, the typical dose for a lumbar spine examination is:
As wavelength increases,frequency decreases and vice versa.
Of the total radiation exposure , 36 % involves:
The smallest particle of an element that retains the characteristics of the element in an atom.
A typical chest x-ray involves a dose of:
According to Einstein matter cannot travel at or or beyond the speed of light.
According to NCRP Report #160, a typical dose for a pelvis and hip examination:
A step up transformer and steps up voltage and step down current.
An ionization chamber circui places:
The ionization chamber is the most common form of automatic exposure control.
Full wave rectification uses:
Choice B looks tempting, but silicone is a substance that is sometimes used in plastic surgery.
A full wave rectified , three phase , 12 pulse x-ray machine produces approximately ………………..% more average photon energy than a full wave rectified ,single phase x-ray machine
Hence the use of the constant 1.41 when calculating heat units for this type of equipment.
According to the anode heel effect, the intensity of radiation is greater at the ………………. side of the x-ray tube
This is where you should place the thicker part being radiographed.
The amount of time needed for an AEc to terminate the exposure is called:
During this time, the exposure is still taking place.
A tube rating chart is used to determine:
Although seldom used, this is based on heat units that would be produced for a given exposure.
Where is the electron beam focused?
Electrons focusing lenses.
Where is the electron image produced?
Photocathode
From where the visible image distributed to viewing or recording media?
Output phosphor
Where is x-ray converted to visiblee light?
Input phosphor . Be sure to review the parts of the image intensifier and know what occurs at each.
A particular x-ray room is “shooting dark”. The problem arises when a change is made from 200 to 300 mA using fixed kVp techniques at 0.16 second.which of the following would lead to an accurate diagnosis of the problem?
Exposure linearity tests the accuracy of the mA stations
An outpatient radiographic room is used primarily for tabletop radiography of the extremities. On a particularly busy afternoon, the radiographers find that similar exposure techniques on successive patients results in substantially different radiographers. Which of the following would lead to an accurate diagnosis of the problem?
Exposure reproducibility tests the accuracy of successive exposures when the same techniqueis used.
Localized lack of sharpness on a radiograph may be diagnosed with which of the following tests?
It will be visualized as ablurry pattern on the image of the mesh.
X-ray beam quantity is expressed in terms of:
Half value layer is the amount of absorbing material that reduces the intensity of the beam by half.
The accuracy of collimation at a 40- inch SID must be:
The accuracy of collimation must be within 2 % of the SID.
The accuracy of kVp at 80 kVp must be:
The accuracy of kVp must be within 4 kVp.
The apparent size of the focal spot as viewed by the image receptor is called the
The actual focal spot is the physical area on the anode from which the x-ray emanate
Which of the following interactions is the primary source of diagnostic x-rays?
The rays appear to be coming from a smaller area. This results in a sharper image.
Which of the following interactions is the primary source of diagnostic x-rays?
X-rays are also produced by the characteristic interaction at the anode.
Which set of exposure factors would produce the greater density?
This technique has the highest mAs and the highest kVp.
Which set of exposures factors would produce the greatest density?
This technique has the highest mAs and the highest kVp.
The components of a grid are:
Be sure to keep lead and aluminium in their proper places.
What is the purpose of a grid?
The primary beam does not contain scatter, contrast goes up when a grid is used, and the dose to the patient actually goes up, not down.
Which of the following list of substances that make up the human body best places them in incresing order of density?
Choice A is nearly correct, but choice D includes tooth enamel.Read all answers carefully.
Bit depth describes:
Bit depth is equal to 2n, where n is the number of bits.
If it is necessary to reduce radiographic density by half, and it is impossible to do so by changing mAs ,the radiographer may:
kVp is governed by the 15% rule.
Compared with film, the dynamic range for digital imaging is:
Grid cutoff may be described as:
Dynamic range is defined as:
Modulation transfer function (MTF) is:
2n(where n equals the number of bits) defines:
A scintillator:
The magnitude of the signal differences in the remnant beam refers to:
A term used to describe the mathematical formula used by the computer to restrict the image
It is critical to choose the correct algorithm for each projection.
When speed is essential in completing an imaging examination , the prefered IR is:
This is currently the fastest way to obtain the image.
Pixel is an acronym meaning:
Improper use of grids with a digital imaging system may cause an artifact known as:
An integrated systems of images and information is called:
Picture Archiving and Communication System
Image noise may be described as:P
The measurement of the luminance of a monitor is called:
Grid radius is:
Violation of the grid radius will cause grid cutoff.
Visibility of an object’s edge may be limited by:
Detective quantum efficiency indicates:
Digital receptors have what kind of response to exposure?
If an angle on the anode is decreased,what effect is there on recorded detail?
A smaller effective focal spt is produced.
If mAs is increased by four times,what is the effect on radiographic contrast?
Although kVp is the controlling factor of contrast, a change in mAs of this magnitude would bury the contrast under excessive density.
If SID is increased,what is the effect on density?
Density decreases as distance is increased, with no changes in exposure factors.
If SID is increased,what is the effect on recorded detail?
A decrease in OID results in less magnification of the image.
A photodiode converts:
If kVp is incresed, what happens to radiographic contrast?
Higher kVp results in more Compton interactions and a more uniform penetration of the part.
Amorphous silicon is used in:
However, this technology is evolving rapidly.
In a conversion from nongrid to a 12: 1 grid, what happens to radiographic contrast?
The grid absorbs scatter radiation . In addition, because no compensation has been made in mAs, the absorption of image- forming rays will be quite noticeable.
If SID is decresed from 60 inches to 30 inches, what happens to magnification?
A shorter SID will rsult in greater magnification
If kVp is decreased, what happens to recorded detail?
There is no correlation between kVp and recorded detail.kVp, and the contrast it provides , does control visibility of detail.
If the IR is removed from tabletop to Bucky, what happens to recorded detail?
This results in increase OID. The point could be made that such a small change(approximately 2 inches) would cause little appreciable effect. It is not likely that the certified exam would attempt to examine such a fine point. However, the single best answer is B, because there is an increase in OID.
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