What is the primary function of the milliampere-seconds during a radiographic exposure?
The regulation of the optical density in the image
The amount of darkening from the black metallic silver deposited in the film is termed?
optical density
What radiographic image that is likely to show the highest optical density?
Gas
The greatest amount of attenuation occurs in what corresponding tissue?
bone
the primary exposure factor that is used for regulating radiographic contrast is
Kilovoltage peak
when a barium-type contrast agent is employed, the desired degree of penetration can be accomplished by using what kilovoltage setting
90-110kvp
a radiographic image is said to possess excessine optical density; this image would appear to be what?
Darker than normal
A reduction of scattered radiation on a radiographic image is likely to occur with a/an?
increased collimation
An increase of 15% in kilovoltage will necessitate a?
50% decrease in the mAs to maintain the same optical density
What pathological change in a patient is likely to require an increase in penetration to maintain the desired optical density?
pulmonary effusion & acromegaly
An abdominal radiographic is taken of a pt measuring 21cm. If all the same conditions are maintained & a second image is taken on a different pt measuring 29 cm, the image will have? (3 things)
1. reduced optical density
2.reduced radiographic contrast
3.reduced spatial resolution
The dose a pt recieves during a diagnostic exposure is directly proportional to the?
mAs employed
A decrease in the amount of scatter produced in a tissue will occur as?
kilovoltage peak setting is decreased
Which of the primary exposure factors has the greatest affect on beam quality, attenuation, & exposure latitude?
kilovoltage peak setting
A radiographic image is produced with insufficient contrast & excessive optical density. Which of the following changes in the exposure factors will best correct for this error?
Decrease the mAs and KVp
An increase in the exposure factors to maintain the desired optical density is often required for pts with?
hydrothorax
An increase in the number of xray photons reaching the image receptor is normally associated with?
increased optical density
Which of the following tissues will have the lowest absorption coefficient to xray photons in the 50-120kvp range?
free air or gas
As the wavelengths of the photons in an xray beam are increased the.....
beam penetration decreases
Radiographic contrast can be defined as the?
difference in the optical densities between adjacent areas of the radiograph
The kilovoltage peak setting is most closely related to the?
radiographic contrast of the image and penetration of the beam
Many skeletal disorders will require an increase in technique due to an overgrowth in bone tissue. These are referred to as?
osteoblastic conditions
An example of a pathological change in a pt that will require an increase of penetration to maintain the desired image quality is?
1. pneumoconiosis
2.Empyema
3. Ascites
A radiographic image is produced using 20 mAs and 74 KVp. Which of the following are likely to occur on a second image taken with 15% increase in the kVp value?
The radiographic contrast of the first image will exceed that of the second
The milliamperage-seconds value employed during an xray exposure is directly proportional to?
the quantity of xrays produced in the exposure
A radiographic image is produced of a high tissue density structure. The area of the radiographic image corresponding to this structure will show a?
low optical density
A radiograph that shows a short scale contast often results from the use of?
low kilovoltage techniques
Which of the following sets of technical factors will result in a radiographic image with the least amount of involuntary motion?
~mA Time kVp
200 100ms 80
400 .05sec 80
800 .03sec 80
800 75ms 70
800 .03sec. 80
The utilization of high kVp (above 90 kVp) for radiographs of the abdomen will result in?
High exposure latitude and long scale contrast
When a fixed kVp technique chart is employed for the selection of exposure factors what is the expected result from underestimating the physical density of tissue in the patient?
A radiographic image with an insufficient optical density
The appropriate degree of penetration for a small body part (finger-hand) is normally accomplished by using a kilovoltage setting in the range of?
55-65kVp
Which of the following is likely to occur if kilovoltage is increased for a radiographic exposure?
1. Increased optical density
2. Longer scale contrast
A beam with a low penetrability is often referred to as a soft beam or?
Low quality beam
Which of the following substances possesses the highest degree of radiopacity?
Lead
A radiographic image produced showing a small degree differential attenuation, is best described as having a?
Low radiographic contrast
In order to see a noticeable change in the optical density, a change of _______ in the mAs is required?
30%
A radiographic image of a child has been obtained using 100 mA 20ms at 74 kVp, but due to movement, the radiographic image is unacceptable. In order to reduce motion, a 60% reduction in time is desired. What new timer setting should be employed?
8ms
What is the primary function of the milliamperage-seconds during a radiographic exposure?
The regulation of the optical density in the image
Window level controls?
how light or dark an image
Window width?
controls the ratio of black to white or contrast
Electronic memory artifact occurs when exposures are taken in to rapid of a sequence. T or F?
true
Thin film transitor is?
~thin layer of transistors on a sub
~will detect either light or electrons
~a transistor will be located @ each pixel can be smaller and can be switched on & off more quickly
Amorphous silicon detector uses?
thin films of silicon integrated with arrays of photodiodes
Direct Capture detectors consists of?
a photoconductor (amorphous selenium (A- Se))
When scintillators are struck by x-rays, what happens?
visible light is emitted proportional to the incident x-ray energy
The scintillation layer in the imaging plate is excited by?
x-ray photons & the scintillator reacts by producing visible light
Direct Conversion DR TFT?
a million-plus pixels can be read & converted to a composite digital imaging in less then 1 sec
The Nyquist theorem states that the sampling frequency must be twice the input signal bandwidth? T or F?
