V2 - Image Production Flashcards
Which factor will increase x-ray beam quantity at the IR without increasing heat units produced by the tube?
Decreased filtration
A breathing technique is planned for a RAO sternum radiograph. The intended exposure is 50 mAs at 75 kVp at 100 cm SID. Which mA station is preferred, assuming the radiographer ensures exposure occurs during the act of inspiration?
50
Which is one function of a picture archiving and communication system (PACS) network?
Downloading images from different imaging modalities
Which term refers to the process by which digital radiography (DR) systems adjust for exposure errors so that the image is displayed with proper brightness and contrast levels?
Automatic rescaling
Which description best defines a histogram?
Graph where x-axis is the amount of exposure read, and the y-axis is the number of pixels
Which best describes anode heel effect?
A phenomenon where x-ray intensity is greater under the cathode
Which term refers to unwanted fluctuations in the brightness of an image?
Noise
Why is it important for the radiographer to observe the mAs readout at the end of each exposure when using AEC?
This value may be used as a basis for calculating manual techniques
Historically, rhenium was alloyed to the tungsten in the filament of valve tubes to increase electron emission. What is the major reason that isn’t used in x-ray tube filaments?
To permit fine control of electron emission by filament heating current
What is the result if the total lead content of a grid is decreased?
Decreased scatter absorption
Which factor would the radiographer choose to maximize recorded detail in the image?
Small focal spot
Pelvis routine calls for an AP with a perpendicular CR, and an axial AP with a 40 degree cephalic angle. Using a caliper measurement, the technique chart yields a perfect set of exposure factors for the perpendicular AP. How will the necessary exposure factors for the axial differ from the perpendicular AP?
Greater measurement, higher kVp and mAs
What could cause a CR image with very noticeable lines uniformly in the same direction over the entire image? (3)
Noise resulting from the plate reader electronics. Grid used with grid frequency equal to the image reader’s laser scan lines. Grid utilized with grid lines running parallel to the laser scan lines of the image reader device.
What would a continuous, fine, horizontal white line across the CR image indicate?
Dirt on the light guide or laser head
Which material is used on most anode disks and is light, strong, and heat-resistant?
Molybdenum
An imaging department, having difficulty obtaining acceptable tangential patella images, has opted to have the post processing mode set to “fixed” for all patella images. Why is this a good choice?
Fixed mode works well for exams where it is difficult to center the image on the IR
A step up transformer with 300 turns in the primary coil is supplied with 220 volts to this primary. How many secondary turns are needed to produce a 66,000 volt output?
90,000 turns
Which is the preferred method for indicating the correct anatomic side on a radiographic image?
Place the side marker directly on the IR prior to exposure
If a radiographer wanted to double image density without doubling the patient’s dose, which action should be taken?
Increase kVp by 15%
In order to increase the number of shades of gray displayed on a digital image what should be done?
Increase window width
What results from utilizing a lower grid ratio?
Lower contrast, but greater error of margin in CR placement
How does emphysema impact radiographic imaging of the chest?
Emphysema is a destructive disease, meaning the chest tissue is more radiolucent
Which component of radiographic noise in digital imaging is controlled by the radiographer?
Quantum mottle
Digital radiography has the ability to produce 16,000 shades of gray. What appropriate bit depth (dynamic range) does this represent?
14 bit depth
Determine the file size for an image with a 512 x 512 matrix and 12 gray scale bit depth.
393216 bytes
How can contrast scale be modified on a digital image? (2)
- Alter window width.
- Collimate more closely.
Assuming other exposure factors remain the same, which SID causes the greatest reduction in x-ray quantity at the IR?
72 inches
Which type of exposure technique chart would allow the radiographer to make small, fine adjustments for orthopedic work?
Variable kVp
Which component of a diagnostic x-ray tube restricts the primary beam to the area of interest?
Collimator
Which CR or DR produces images with the highest spatial resolution?
Amorphous selenium - direct capture DR
A radiographer is performing a portable abdomen is using an IR with a 8:1 grid. The radiographer knows a technique for the abdomen using a 12:1 grid is 80 kVp using 50 mAs. Which would the new technique be in order to maintain image quality?
80 kVp @ 40 mAs
How does a radiographer maximize signal to digital image receptors? (3)
- Longer exposure time.
- Compression of the body part.
- Shorter SID.
Place the following mAs selections in order from which will cause the greatest exposure to the IR to the least exposure, if all other factors remain.
highest mAs to the lowest
Which advantage does a 500 mA station have over a 200 mA station?
Increased photon flux to the IR
Which pathologic condition will result in the greatest attenuation of the beam?
Ascites
If a transformer has a great number of turns in the secondary coil than in the primary coil, how will the output voltage be affected?
Increased
In a conventional tomography, the radiographer is able to control the thickness of the tomographic slice by altering which of the following?
Exposure angle
In which way can the radiographer minimize motion due to peristalsis?
Decreases exposure time
At 50 inch SID, how closely must the ex-ray beam and the light field be aligned?
1 inch
Which statement is correct regarding the relationship of patient dose to exposure index (EI)?
EI gives an approximation of the patient’s dose
If CR imaging plates haven’t been used, how often should they be erased?
48 hours
Which function are RIS networks are capable of performing?
Tracking radiology scheduling information
A finished radiograph has marked quantum mottle. Positioning, collimation, and identification markers are correct. Which action should the radiographer take?
Repeat the image with an appropriate increase in technical factors
If all the bucky digital images from one radiographic room seem to appear excessively noisy, what might the radiographer suspect?
The AEC is set at an inappropriate speed class
What is a method of electronic display resolution quality control testing?
Society of Motion Picture and Television Engineers (SMPTE) test pattern
What is the purpose of shuttering?
To black out areas of light and make fine details more visible
How much compensation is needed for a change to a small focal spot?
None
Which will increase the appearance of noise in a digital image, assuming only the named factor in each response is changed?
Large matrix
If 7 mAs provide optimal density without a grid, which mAs should be used with a 12:1 grid?
GCF of 5
CR imaging creates images with poorer resolution than that of film screen. What compensates for this loss of resolution?
The wide latitude
