RAD REVIEW 4.2: Equipment Operation and Quality

45

According to the line-focus principle, to produce an effective focal spot smaller than the actual focal spot the anode target angle must be less than ______ degrees. A 15 B 35 C 45 D 60

the indirect DR system converts the remnant beam to visible light.

An Indirect DR system will always have a lower detective quantum efficiency and a lower spatial resolution than an equivalent Direct DR system. This is because A the indirect DR detector utilizes an electron trap to capture the signal. B the direct DR system converts the remnant beam to visible light. C the indirect DR system stores the image data as an analog signal. D the indirect DR system converts the remnant beam to visible light.

Fill factor

An important feature of the pixel in a flat-panel TFT digital detector active matrix array is the: A Nyquist frequency B Fill factor C Image lag D Modulation transfer function

window width

Changes between the images shown in the figures below represent changes made to (knee xrays)

1, 2, and 3

Component parts of a CT gantry include 1. high-voltage generator 2. multidetector array 3. x-ray tube A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

Widening of the histogram

Off-focus and scatter radiation outside of the exposure field when using CR can cause: A Narrowing of the histogram B Widening of the histogram C Improper alignment of the exposure field D High contrast

CR

Q 7.10: Which of the following possesses the widest dynamic range? A ALARA B PBL C AEC D CR

Pixels/mm or pixel density

Sampling frequency in computed radiography (CR) is expressed as: A The TFT array size B An inverse relationship between focal spot size and matrix size C The light spread between the image plate and the light guide of the scanner D Pixels/mm or pixel density

detector array.

The part of a CT imaging system made of thousands of solid-state photodiodes is the A gantry. B detector array. C collimator assembly. D x-ray tube.

12 cm

Using a multifield image intensifier tube, which of the following input phosphor diameters will provide the greatest magnification? A 35 cm B 25 cm C 17 cm D 12 cm

Beyond a certain exposure level, a large number of pixels will be at maximum digital value (black), resulting in loss of visibility of anatomical structures in that region.

"Saturation" of an image in CR means that: A The CR reader has difficulty converting insufficient exposure signals to produce a diagnostic image; all electronic enhancement mechanisms are maximized B Beyond a certain exposure level, a large number of pixels will be at maximum digital value (black), resulting in loss of visibility of anatomical structures in that region. C There is a large amount of scatter radiation that is contributing to loss of anatomical image detail due to loss of contrast, thus decreasing diagnostic quality of the image D The CR image reader has adequately, and completely, read all the exposure intensities from the pixels resulting from the exposure

Photomultiplier tube

A device contained within many CR readers that functions to convert light energy released by the PSP into electrical energy, is called a: A Transilluminator B Photomultiplier tube C Light gate D Penetrometer

14,000

A radiographic technique of 80 kilovoltage peak (kVp), 500 milliamperes (mA), and 0.25 seconds is selected for a radiographic exposure. How many heat units (HU) would be produced from this single exposure on a high frequency x-ray unit? A 10,000 B 13,500 C 14,100 D 14,000

1 only

A star pattern is used to measure 1. focal spot resolution. 2. scatter resolution. 3. SID resolution. A 1 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3

1 and 2 only

Advantages of battery-powered mobile x-ray units include their 1. ability to store a large quantity of energy 2. ability to store energy for extended periods of time 3. lightweight quality A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

Scanned projection radiography (SPR)

All of the following are equipment options that may be used to record the anatomical image in mobile radiography, except: A Tethered flat panel B Remote (wireless) digital flat panel array C Scanned projection radiography (SPR) D Conventional radiographic film

Excessive beam limiting (collimation)

All of the following are factors that cause low contrast in CR images, except: A High kVp B Inadequate grid efficiency or no grid C Excessive beam limiting (collimation) D Incomplete erasure of the image plate

Edge enhancement

All of the following are potential digital pre-processing problems, except: A Edge enhancement B Defective pixel C Image lag D Line noise

exposure switches must be the two-stage type

All the following statements regarding mobile radiographic equipment are true except A the exposure cord must permit the operator to stand at least 6 ft from the patient, x-ray tube, and useful beam B exposure switches must be the two-stage type C a lead apron should be carried with the unit and worn by the radiographer during exposure D the radiographer must alert individuals in the area before making the exposure

the milliamperage meter

All the following x-ray circuit devices are located between the incoming power supply and the primary coil of the high-voltage transformer except A the timer B the kilovoltage meter C the milliamperage meter D the autotransformer

Phantom image artifact

Backscatter on a digital image can cause an artifact called a A Phantom image artifact B Moiré artifact C Static artifact D Grid cutoff artifact

Initialization

Before a flat-panel detector can be used for a radiographic exposure, it must be prepared. This preparation is referred to as: A Propagation B Initialization C Augmentation D Instrumentation

preventive maintenance.

Biomedical repair technicians often perform repairs of diagnostic imaging equipment without a complaint of malfunction, but rather to test and replace parts of the machine known to experience wear and tear with normal operation. These types of repairs are called A acceptance testing. B quality assurance repairs. C service call repairs. D preventive maintenance.

The thin film transistor (TFT) detector element (DEL) size

Cassetteless digital systems have a fixed spatial resolution determined by: A The image plate laser divergence B The focal spot size used C The thin film transistor (TFT) detector element (DEL) size D The proximity of the phosphor screen crystals

1, 2, and 3

Characteristics of DR imaging include solid-state detector receptor plates a direct-capture imaging system immediate image display A 1 only B 1 and 3 only C 2 and 3 only D 1, 2, and 3

1 and 3 only

Characteristics of an effective grid interspace material include 1. Low atomic number 2. Absorbs moisture 3. Radiolucent A 1 only B 2 only C 1 and 3 only D 1, 2, and 3

radiopaque objects

Congruence of the x-ray beam with the light field is tested using A a pinhole camera B a star pattern C radiopaque objects D a slit camera

The secondary current is decreased.

Consider a step-up transformer that increases the voltage induced on the secondary side of the transformer. What is the relationship of the primary side current to the secondary side current? A The secondary current is stepped up. B The secondary current is decreased. C There is no change in the current through the step-up transformer. D The secondary current is increased.

slip rings.

Continuous rotation of the CT x-ray tube and detector array, with simultaneous movement of the CT couch, has been accomplished through implementation of A additional cables. B slip rings. C multiple rows of detectors. D electron beam CT.

1 only

Deposition of vaporized tungsten on the inner surface of the x-ray tube glass window 1. acts as additional filtration 2. results in increased tube output 3. results in anode pitting A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

charge-coupled device (CCD)

Digital fluoroscopy units use which of the following devices in lieu of a television camera tube? A charge-coupled device (CCD) B photometer C photomultiplier tube D light gate

1, 2, 3

Excessive anode heating can cause vaporized tungsten to be deposited on the port window. This can result in 1. decreased tube output. 2. tube failure. 3. electrical arcing. A 1 only B 2 only C 1 and 2 only D 1, 2, and 3

line-focus principle

Figure 5-7 illustrates the A inverse-square law B line-focus principle C reciprocity law D anode heel effect

Collimator accuracy test

Figure 7-5 illustrates which of the following? A Screen resolution test B Nine-penny test C Collimator accuracy test D Focal-spot size test

Excessive windowing

Histogram data that is skewed relative to the values of interest (VOI) of the histogram analysis used for a particular exam may be caused by all of the following, except: A Anatomical structures not centered to the IP B Excessive windowing C The X-ray beam is not correctly aligned to the edges of the IP D The beam edge is irregular because of overlap of a radiopaque shadow, such as a gonadal shield

30

If 82 kVp, 300 mA, and 0.05 second were used for a particular exposure using 3-phase, 12-pulse equipment, what mAs would be required, using single-phase equipment, to produce a similar radiograph? A 7.5 B 20 C 30 D 50

10

If 85 kV and 20 mAs were used for a particular abdominal exposure with single-phase equipment, what mAs would be required to produce a similar radiograph with 3-phase, 12-pulse equipment. A 40 B 25 C 20 D 10

6 in.

If the distance from the focal spot to the center of the collimator's mirror is 6 in., what distance should the illuminator's light bulb be from the center of the mirror? A 3 in. B 6 in. C 9 in. D 12 in.

110 kV

If the primary coil of the high-voltage transformer is supplied by 220 V and has 200 turns, and the secondary coil has 100,000 turns, what is the voltage induced in the secondary coil? A 40 kV B 110 kV C 40 V D 110 V

1, 2, and 3

Image quality in digital fluoroscopy is influenced by 1. pixel size. 2. contrast. 3. noise. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

The Nyquist frequency, which is 1/2X the pixel pitch (mm)

In digital imaging, the maximum spatial resolution is equal to: A The Nyquist frequency, which is 1/2X the pixel pitch (mm) B The wavelength of the detector system's analog-to-digital convertor's electrical signal C The distance between the silver halide crystals in the image receptor D The detective quantum efficiency of the imaging system; this should be at least 2X the frequency of the analog-to-digital convertor electrical signal

All of these are correct actions

In order to avoid background radiation artifacts when using CR, it is important to: A Erase all image plates that have not been used for 48 hours B Erase all image plates if there is any question about how long it has been since the plate has been erased C Erase an image plate if there is any doubt as to when it was last erased, especially in the case of pediatric radiography D All of these are correct actions

105

In the radiographic rating charts shown below, what is the maximum safe kVp that may be used with the 1-mm focal spot, single-phase x-ray tube, using 300 mA and 1/50-second exposure? A 80 B 95 C 105 D 112

Rescaling

Once the values of interest numbers are assigned, what is the process that then adjusts an over/underexposed image? A Values B Brightness C Rescaling D Image contrast

To allow the radiologist to split the PACS monitor and display the current image and a prior image side-by-side for comparison

One reason why only one image is preferred per image plate is: A To ensure that the anatomical part is properly centered to avoid undercutting of the image B To allow the radiologist to split the PACS monitor and display the current image and a prior image side-by-side for comparison C To ensure optimal radiation safety, since only one image is exposed on one image plate D To reduce the chances of grid cutoff artifacts

Display matrix size

Quality Control (QC) testing is used to evaluate digital display monitors in all of the following ways, except A Display luminance response B Display resolution C Display matrix size D Display noise

Daily

Quality control testing of digital display monitors should be conducted A Daily B Weekly C Monthly D Annually

(1) 1. Technologists selects body part... (2) 5. exposure switch is fully pressed... (3) 4. Remnant beam exits the patient... (4) 6. light emission from scintillation layer is converted... (5) 2. TFT array sorts and transmits electronic signal (6) 3. Processing software applies body part / projection-specific LUT... (7) 7. Adjusted data set is sent to console display...

Sort the steps of image formation if an indirect DR system is used: 1. Technologist selects body part and projection from the control console's APR menu. 2. TFT array sorts and transmits electronic signal to the image processing software. 3. Processing software applies body part/projection-specific LUT to incoming data stream. 4. Remnant beam exits the patient and interacts with the cesium iodide layer of the image receptor. 5. Exposure switch is fully pressed, generating and broadcasting an x-ray beam that exits the tube. 6. Light emission from the scintillation layer is converted to electric charge at the photodetector. 7. Adjusted data set is sent to console display.

transfer the output-phosphor image to the TV monitor.

TV camera tubes used in image intensification, such as the Plumbicon and Vidicon, function to A increase the brightness of the input-phosphor image. B transfer the output-phosphor image to the TV monitor. C focus and accelerate electrons toward the output phosphor. D record the output-phosphor image on the IR.

1 and 2 only

The advantages of capacitor-discharge mobile x-ray equipment include 1. compact size 2. light weight 3. high kilovoltage capability A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

1, 2, and 3

The batteries in battery-operated mobile x-ray units provide power to 1. the x-ray tube 2. machine locomotion 3. the braking mechanism A 1 only B 2 only C 1 and 2 only D 1, 2, and 3

A. Improved image quality for unequal thickness anatomical parts B. decreased image unsharpness D. smaller effective focal spot

The benefits of utilizing a smaller target angle include which of the following? (select the three that apply) A Improved image quality for unequal thickness anatomical parts B Decreased image unsharpness C Increased image unsharpness D Smaller effective focal spot E Larger effective focal spot

spinning top

The device used to test the accuracy of the x-ray timer is the A densitometer B sensitometer C penetrometer D spinning top

Raster pattern

The electron beam in a television cathode ray tube (CRT) is projected onto the output phosphor in a: A Vertical pattern B Fixed direct beam C Broad field D Raster pattern

The mAs increases during the exposure, called "mAs creep"

The following are disadvantages of a capacitor-discharge mobile unit, except: A The mAs increases during the exposure, called "mAs creep" B The capacitor may continue to discharge after the exposure C The actual kilovoltage achieved during an exposure is significantly lower than the set kVp D At lower kVp settings, the capacitors discharge more slowly and, therefore, a considerable residual kV may exist after the desired exposure time

timer accuracy in a three-phase x-ray machine.

The image in Figure 6-6 was obtained while testing A rectifier operation in a single-phase x-ray machine. B rectifier operation in a three-phase x-ray machine. C timer accuracy in a single-phase x-ray machine. D timer accuracy in a three-phase x-ray machine.

is much larger than the output phosphor

The image intensifier's input phosphor differs from the output phosphor in that the input phosphor A is much larger than the output phosphor B emits electrons, whereas the output phosphor emits light photons C absorbs electrons, whereas the output phosphor absorbs light photons D is a fixed size, and the size of the output phosphor can vary

ADC

The luminescent light emitted by the PSP is converted to a digital image by the A DAC B scanner-reader C ADC D helium-neon laser

Slow-scan direction

The movement of the IP through the transport system of a CR reader is referred to as the: A Slow-scan direction B Charge-coupled direction C Nyquist direction D Fast-scan direction

Field centered to IP with four collimation margins parallel to the IP edges

The optimal alignment of the anatomical part being imaged for all digital receptors should be: A Field centered to IP with at least two collimation margins and parallel to the IP edges B Centered anywhere on the IP, but having four distinct collimation margins, regardless of parallel orientation to the IP edges C Centered to the IP with at least one collimation margin aligned to nearest edge of IP D Field centered to IP with four collimation margins parallel to the IP edges

1 and 2 only

The output phosphor can be coupled with the Vidicon TV camera or charge-coupled device (CCD) via 1. fiber optics. 2. an image distributor or lens. 3. closed-circuit TV. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

2 and 3 only

The primary parts of the cathode include the 1. focal track. 2. filament. 3. focusing cup. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

0.05 second

The radiograph illustrated in the figure below was made using a single-phase, full-wave-rectified unit with a timer and rectifiers that are known to be accurate and functioning correctly. What exposure time was used to produce this image? A 1/10 second B 0.05 second C 1/12 second D 0.025 second

single-phase, full-wave rectified unit

The radiograph shown in Figure 5-5 was made using a A three-phase, 6-pulse rectified unit B three-phase, 12-pulse rectified unit C single-phase, full-wave rectified unit D high-frequency rectified unit

Grid

The radiographer must consider focal range when using which of the following accessory devices? A Collimator B Grid C Immobilization device D Lead marker

Expose one image on the smallest IP available with collimation margins aligned parallel to the edges of the IP

The safe approach to avoid an exposure field recognition error when using CR is to: A Expose one image on the smallest IP available with collimation margins aligned parallel to the edges of the IP B Expose multiple images on one IP, but make sure all collimation margins overlap C Expose one image on the IP, but do not collimate D Expose multiple images on one IP, but make sure all collimation margins are parallel to each other and do not overlap

grid-controlled

The type of x-ray tube designed to turn on and off rapidly, providing multiple short, precise exposures, is A high speed B grid-controlled C diode D electrode

rectification

The x-ray tube is a DC electrical device, while the transformers that power it are AC devices. An arrangement of diodes between the two converts the AC voltage waveform into a pulsed DC output. The process of converting an electrical signal from AC into DC is called A electrification B rectification C amplification D ionization

Halo effect artifact

Too much edge enhancement of the image in digital systems can cause an unwanted artifact called the: A Photoelectric effect artifact B Scaling artifact C Hounsfield artifact D Halo effect artifact

1 and 2 only

Types of moving grid mechanisms include 1. oscillating. 2. reciprocating. 3. synchronous. A 1 only B 1 and 2 only C 1 and 3 only D 2 and 3 only

2 and 3 only

Use of a portion of the input phosphor during fluoroscopy, rather than the entire input phosphor, will result in 1. a larger field of view (FOV). 2. a magnified image. 3. improved spatial resolution. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

12 cm

Using a multifield image intensifier tube, which of the following input phosphor diameters will require the highest patient dose? A 35 cm B 25 cm C 17 cm D 12 cm

Hospital information system

What does HIS stand for under hospital organizations? A Healthcare information system B Health information system C Hospital information system D Housing information system

Picture archiving and communication system

What does the term PACS stand for in digital imaging? A Picture archiving and communication system B Pixel archiving and contrast system C Patterns archiving and communication system D Pair archiving and communication system

To direct electrons to the focal track

What is the function of the x-ray tube component numbered 2 in Figure 7-18? A To release electrons when heated B To release light when heated C To direct electrons to the focal track D To direct light to the focal track

The aluminum layer absorbs backscatter radiation, preserving the signal-to-noise ratio for the image.

What is the purpose of the aluminum layer in a CR (photostimuable phosphor) cassette? A The aluminum layer is used to filter low energy x-rays in the primary beam, saving patient dose. B The aluminum layer reflects blue light toward the photomultiplier tube during image processing. C The aluminum layer traps the electrons, which are later released via stimulation with red laser light. D The aluminum layer absorbs backscatter radiation, preserving the signal-to-noise ratio for the image.

Stator

What x-ray tube component does the number 6 in Figure 5-4 indicate? A Anode stem B Rotor C Stator D Focal track

1, 2, and 3

When using the smaller field in a dual-field image intensifier, 1. a smaller patient area is viewed. 2. the image is magnified. 3. the image is less bright. A 1 only B 1 and 3 only C 2 and 3 only D 1, 2, and 3

1 and 2 only

Which among the following components is (are) part of the gantry of a CT imaging system? 1.X-ray tube 2.Detector array 3.Control panel A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

A. x-ray tube C. operating console D. high voltage generator

Which of the following are the principle components of the x-ray imaging system? (select the three that apply) A X-ray tube B Patient table C Operating console D High voltage generator E Printer/CD burner

1.2-mm focal spot, 92 kVp, 1.5 mAs

Which of the following combinations would pose the least hazard to a particular anode? A 1.2-mm focal spot, 92 kVp, 1.5 mAs B 0.6-mm focal spot, 80 kVp, 3 mAs C 1.2-mm focal spot, 70 kVp, 6 mAs D 0.6-mm focal spot, 60 kVp, 12 mAs

Quantum noise

Which of the following denotes undesirable fluctuations in brightness, dependent on the number of x-ray photons reaching the IR? A Grainy image B Artifacts C Degrades D Quantum noise

Motor

Which of the following devices converts electrical energy to mechanical energy? A Motor B Generator C Stator D Rotor

Smoothing

Which of the following digital post-processing methods remove high-frequency noise from the image? A Edge enhancement B Windowing C Smoothing D Aliasing

1, 2, and 3

Which of the following is (are) tested as part of a QC program? 1. Beam alignment 2. Reproducibility 3. Linearity A 1 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3

1, 2, and 3

Which of the following is (are) tested as part of a quality control (QC) program? 1. Beam alignment 2. Reproducibility 3. Linearity A 1 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3

Flat panel image receptor

Which of the following is a device that can be used in lieu of an image intensifier/charge-coupled device combination in digital fluoroscopy? A Charge-coupled device B Flat panel image receptor C photometer D photomultiplier tube

Vidicon

Which of the following is a type of television camera tube that converts a visible image on the output phosphor of the image intensifier into an electronic signal? A Ionization chamber B Vidicon C Charge-coupled device D Cathode ray tube

MF = source-image-distance / source-object-distance

Which of the following is the formula used to determine magnification factor (MF)? A MF = source-image-distance / object-image-distance B MF = source-image-distance / source-object-distance C MF = source-object-distance / source-image-distance D MF = object-image-distance / source-image-distance

1 only

Which of the following is/are components of the secondary, or high voltage, side of the x-ray circuit? 1. Rectification system 2. Autotransformer 3. kV meter A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

Exposure field recognition errors may occur

Which of the following may occur if the X-ray exposure field is not properly collimated, positioned, and sized? A Modulation transfer function failure B Moiré artifact C Exposure field recognition errors may occur D Ghost artifact

Tethered or wireless flat-panel digital mobile units

Which of the following mobile radiography applications enables the radiographer to view the radiographic image before leaving the patient? A Fixed digital units of any type B Tethered or wireless flat-panel digital mobile units C Portable units using conventional radiographic film D Battery operated conventional radiography mobile units

Slit camera

Which of the following requires two exposures to evaluate focal-spot accuracy? A Pinhole camera B Slit camera C Star pattern D Bar pattern

1 and 3 only

Which of the following statements regarding dual x-ray absorptiometry is (are) true? 1. Radiation dose is low. 2. Only low-energy photons are used. 3. Photon attenuation by bone is calculated. A 1 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3

1 only

Which of the following voltage ripples is (are) produced by single-phase equipment 1. 100% voltage ripple 2. 13% voltage ripple 3. 3.5% voltage ripple A 1 only B 2 only C 2 and 3 only D 1, 2, and 3

1 and 2 only

Which of the following x-ray circuit devices operate(s) on the principle of mutual induction? 1. High-voltage transformer 2. Filament transformer 3. Autotransformer A 1 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3

Number 1

Which of the x-ray circuit devices shown in Figure 6-5 operates on the principle of self-induction? A Number 1 B Number 3 C Number 5 D Number 7

1 only

Which of the x-ray circuit devices shown in Figure 7-16 operates on the principle of self-induction? 1. Number 1 2. Number 2 3. Number 3 A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3

Stator

Which part of an induction motor is located outside the x-ray tube glass envelope? A Filament B Focusing cup C Stator D Rotor

1, 2, and 3

X-ray tubes used in CT differ from those used in x-ray, in that CT x-ray tubes must 1. have a very high short-exposure rating 2. be capable of tolerating several million heat units 3. have a small focal spot for optimal resolution A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3