hesi image production v3

With all other factors remaining the same, which source-to-image-receptor-distance (SID) results in the greatest exposure to the image receptor (IR)? A. 40 inches. B. 72 inches. C. 44 inches. D. 60 inches.

a

Which device provides the required amount of voltage for x-ray production? A. Transformer. B. Battery. C. Rheostat. D. Capacitor.

a A transformer provides a predetermined amount of voltage for the production of x-rays. A battery is a device that produces electrons and is capable of storing a charge for an extended period. A capacitor is a device used for temporary storage of an electrical charge. A rheostat is an adjustable form of resistor.

All other factors remaining the same, how will increasing the source to image receptor distance (SID) from 40 inches to 60 inches affect the appearance of a radiographic image? A. Decreased magnification. B. Decreased sharpness. C. Increased shape distortion. D. Increased density.

a

At which location is the ionization chamber located in an automatic exposure control (AEC) device? A. Between the grid and the image receptor (IR). B. Between the patient and the image receptor (IR). C. Between and the x-ray tube and the patient. D. Between the image receptor (IR) and the wall.

a

How does aliasing appear radiographically when using computed radiography (CR)? A. Two superimposed images, slightly out of alignment. B. A white line along the length of the image. C. Black lines, branching across the image. D. Excessive noise on the image.

a

Opening the collimators wider than necessary using digital radiography has which effect on image quality? A. Image noise is increased. B. There is no effect on image quality. C. The contrast resolution of the image is decreased. D. The spatial resolution of the image is increased.

a

Which acronym describes a network of computers that manages digital images? A. PACS. B. RIS. C. HIS. D. DICOM.

a

Which device is located in the primary section of a general x-ray circuit? A. Timer circuit. B. Rheostat. C. Step-down transformer. D. Milliampere (mA) meter.

a

Which effect does switching to the small focal spot size have on the manifest image? A. Image unsharpness decreases. B. Image density increases. C. Size distortion decreases. D. Scale of contrast increases.

a

Which factor will have the greatest impact on decreasing recorded detail or spatial resolution? A. Motion. B. Source-to-image-receptor-distance (SID). C. Object-to-image-receptor-distance (OID). D. Focal spot size.

a

Which milliampere seconds (mAs) value should be selected for a patient measuring 30 centimeters if 22 mAs is optimal for a patient measuring 25 centimeters? A. 44 mAs. B. 40 mAs. C. 33 mAs. D. 28 mAs.

a

Which post-processing action is always acceptable? A. Annotating with an upright marker to show the patient was in an erect position. B. Placing an anatomically appropriate annotated marker showing which side is the left side. C. Using electronic masking to eliminate unnecessary anatomy. D. Changing the processing algorithm to a different procedure.

a Annotating with an upright marker to show the patient was in the upright position is an appropriate measure. Use of electronic masking to remove unnecessary anatomy should never be done. If the anatomy has been exposed, it should be included on the image. Placing an anatomically appropriate marker annotation is appropriate if the marker on the original image is not visible. However, this is not the best practice. Even though an image may be improved by changing the processing algorithm, this should not be done.

Which post-processing techniques may be used with digital imaging? (Select the three that apply.) A. Electronic masking. B. Filtering. C. Smoothing. D. Automatic brightness control (ABC). E. Quantum noise.

a b c

A radiograph of optimal density is produced at 15 milliampere seconds (mAs) and a source to image receptor distance (SID) of 40 inches. Which mAs value is required to produce the same radiographic density if this exam is repeated at an SID of 48 inches? A. 16 B. 22 C. 10 D. 18

b

Consider these different abdomen images of the same patient. What most likely caused the difference in these images? A. Image B was produced with a large effective focal spot (EFS). B. Image A was produced at a shorter source to image receptor distance (SID). C. Image A was produced with less object to image receptor distance (OID). D. Image B was produced with a larger image receptor (IR).

b

The radiographer is using automatic exposure control (AEC) on a sinus examination. The quality control technologist directs the radiographer to repeat the parietoacanthial (Water's) projection with increased contrast. Thus the radiographer changes kilovolts peak (kVp) from 85 to 72. What change to AEC settings or positioning is needed? A. Align the head about 1" higher relative to the central detector cell. B. No change. C. + 1 on the density control. D. - 1 on the density control.

b

Which advantage is gained by increasing the standard source to image receptor distance (SID) from 40 inches to 48 inches? A. Increased radiographic contrast. B. Increased image resolution. C. Increased x-ray tube life. D. Increased signal to noise ratio (SNR).

b

Which effect does a step-up transformer have on voltage and current? A. Voltage and current are increased. B. Voltage is increased and current is decreased. C. Voltage and current are decreased. D. Voltage is decreased and current is increased.

b

Which effect will a low signal-to-noise ratio (SNR) have on the appearance of a digital radiographic image? A. Decreased spatial resolution. B. Decreased contrast resolution. C. Decreased brightness. D. Decreased dynamic range.

b

Which image, when performed according to normal standards, will demonstrate the greatest magnification of the anatomy of interest? A. Lateral forearm. B. Lateral cervical spine. C. Anteroposterior (AP) lumbar spine. D. Posteroanterior (PA) hand.

b

Which set of exposure factors is most likely to provide clear visualization of the upper cervical spine through the mandible when performing an anteroposterior (AP) "wagging jaw" projection (Ottonello Method)? A. 85 kilovolts peak (kVp), 200 milliamperes (mA), 0.2 seconds. B. 75 kilovolts peak (kVp), 25 milliamperes (mA), 2.0 seconds. C. 85 kilovolts peak (kVp), 400 milliamperes (mA), 0.1 seconds. D. 75 kilovolts peak (kVp), 100 milliamperes (mA), 0.5 seconds.

b The Ottonello Method for the cervical spine requires the patient to perform a chewing motion during the exposure. An exposure time of at least 1 to 2 seconds is required to allow for blurring of the mandible and visualization of C1 and C2. The other techniques listed do not allow for sufficient exposure time to produce this effect.

The center of the x-ray beam must be aligned to the center of the bucky tray to within what percent of the source to image receptor distance (SID)? A. 3%. B. 1%. C. 2%. D. 4%.

b The center of the x-ray beam must be aligned to the center of the bucky tray to within 1% of the SID.

Which factors affect spatial resolution in digital imaging? (Select the two that apply.) A. Increased pixel pitch. B. Greater number of pixels. C. Smaller pixels. D. Smaller matrix size. E. Increased bit depth.

b c

A portable chest x-ray is taken at 56 inches using 12 milliampere-seconds (mAs) at 72 kilovolts peak (kVp). Which technique should the radiographer use if the chest x-ray is repeated in the radiology department at 72 inches to maintain density? A. 6 mAs at 84 kVp. B. 6 mAs at 72 kVp. C. 24 mAs at 72 kVp. D. 24 mAs at 60 kVp.

c

An image of the abdomen demonstrates appropriate density and scale of contrast, but motion blur is present due to peristalsis. If the original image was obtained with a 200 milliampere (mA) station and an exposure time of 0.35 seconds, which set of technical factors will produce a comparable exposure while minimizing motion artifact? A. 300 mA and 0.23 seconds. B. 400 mA and 0.35 seconds. C. 500 mA and 0.14 seconds. D. 100 mA and 0.7 seconds.

c

Assuming that automatic exposure control is to be used, what backup milliampere-seconds (mAs) are sufficient for a large (100 kg) adult anteroposterior (AP) lumbar spine done at 80 kilovolts peak (kVp)? A. 40 mAs. B. 80 mAs. C. 100 mAs. D. 60 mAs.

c

How does a wide window width affect an image? A. Increases contrast. B. Increases brightness. C. Decreases contrast. D. Decreases brightness.

c

In cassette-based computed radiography (CR) systems, the photostimulable phosphor plate is made of which material? A. Calcium tungstate. B. Amorphous silicon. C. Barium fluorohalide. D. Cesium iodide.

c

The collimator light must be aligned to the radiation field to within what percent of the source to image distance (SID)? A. 4%. B. 3%. C. 2%. D. 5%.

c

Which combination results in an image with the greatest recorded detail? A. 2 inch object-to-image-receptor-distance (OID), 44 inch source-to-image-receptor-distance (SID), 0.6 mm focal spot size (FSS). B. 4 inch object-to-image-receptor-distance (OID), 72 inch source-to-image-receptor-distance (SID), 1.2 mm focal spot size (FSS). C. 2 inch object-to-image-receptor-distance (OID), 72 inch source-to-image-receptor-distance (SID), 0.6 mm focal spot size (FSS). D. 4 inch object-to-image-receptor-distance (OID), 44 inch source-to-image-receptor-distance (SID), 1.2 mm focal spot size (FSS).

c

Which is an advantage of digital imaging systems compared to traditional film-screen systems? A. Higher spatial resolution. Incorrect B. Reduced image noise. C. Improved contrast resolution. D. Less sensitivity to scatter.

c

Which milliampere-seconds (mAs) setting is most likely to produce quantum mottle? A. 100 mAs. B. 25 mAs. C. 2.5 mAs. D. 50 mAs.

c

Which technical factor increases the number of x-ray photons reaching the image receptor (IR)? A. Small focal spot size. B. Decreased milliamperage (mA). C. Increased milliamperage (mA). D. Large focal spot size.

c

A fixed kilovolts peak (kVp)-variable milliampere (mA) chart recommends exposure factors of 70 kVp and 32 mAs for an anteroposterior (AP) abdomen projection on an average-size patient. Based on this chart, which fixed kVp technique is most appropriate for an AP projection of a double contrast upper gastrointestinal (UGI) image? A. 70 kVp, 42 mAs. B. 80 kVp, 16 mAs. C. 60 kVp, 64 mAs. D. 90 kVp, 8 mAs

d

How are automatic exposure control (AEC) devices for mammography different than those used with diagnostic radiography? A. Exposures are indirectly terminated. B. Detector location is fixed. C. Fewer detectors are available. D. Greater accuracy is required.

d

How will raising the window level affect the digital image? A. Decreases brightness. B. Decreases contrast. C. Increases contrast. D. Increases brightness.

d

Which device in the x-ray circuit changes alternating current to direct current? A. Filament. B. Autotransformer. C. Rheostat D. Rectifier.

d

Which is the best way to avoid excessive quantum noise when using cassette-based digital systems? A. Calibrate the system to operate at a higher speed class. B. Erase the imaging plate prior to each exposure. C. Adjust the window level to decrease image brightness. D. Increase the amount of exposure to the image receptor.

d

Which is the primary advantage of a rotating anode? A. More heat is generated at the filament. B. More heat is generated at the target. C. Less heat is generated at the filament. D. Less heat is generated at the target.

d

Which milliamperage (mA) station will result in a milliampere seconds (mAs) value of 44 if the exposure time is 0.11 seconds? A. 44 mA. B. 444 mA. C. 40 mA. D. 400 mA.

d

Which radiopaque marker is image-appropriate after micturition has taken place? A. Post-evacuation. B. Decubitus. C. Upright. D. Post-void.

d

Which scenario causes foreshortening of the anatomy on the image? A. The entire arm in contact with the image receptor, and the central ray directed perpendicular to the long axis of the arm. B. A two inch gap between the arm and the image receptor (IR), and the central ray directed perpendicular to the long axis of the arm. C. The arm flat against the image receptor (IR), and the central ray angled along the long axis of the arm. D. The humerus in contact with the image receptor (IR), the forearm lifted off the image receptor, and the central ray directed perpendicular to the long axis of the humerus.

d

Which substance is added to the x-ray tube housing to increase heat dissipation? A. Methane. B. Water. C. Liquid nitrogen. D. Oil.

d

Which term refers to a graphical representation of pixel values? A. Exposure indicators. B. Algorithm. C. Modulation transfer function (MTF). D. Histogram.

d

Which term refers to the positive electrode of the x-ray tube? A. Diode. B. Triode. C. Cathode. D. Anode.

d

Which x-ray tube orientation represents the correct application of the anode heel effect? A. The cathode end is positioned toward the elbow for a lateral humerus projection. B. The anode end is positioned toward the elbow for a lateral forearm projection. C. The cathode end is positioned toward the knee for an anteroposterior (AP) femur projection. D. The anode end is positioned toward the head for an anteroposterior (AP) thoracic spine projection.

d

When using digital imaging, which has the greatest influence on contrast? A. Milliampere-seconds (mAs). B. Kilovolts peak (kVp). C. Modulation transfer function (MTF). D. Lookup table (LUT).

d In digital imaging, a LUT (C) assigns predetermined grayscale values. KVp (A) controls contrast in film-screen imaging. MAs (B) does not affect contrast. MTF (D) is related to spatial resolution. Johnston and Fauber, Essentials of Radiographic Physics and Imaging, Ch. 12, "Using digital receptors," p. 164. Carter and Veale, Digital Radiography and PACS, 2nd ed., Ch. 3, "Look-up table," p. 42.

Which procedure is most effective for reducing localized image blurring caused by involuntary patient motion? A. Take exposures during suspended respiration. B. Clearly explain each procedure. C. Use immobilization techniques. D. Decrease exposure times.

d Involuntary motion, often due to peristalsis or tremors, may result in localized image unsharpness. This type of motion artifact is most effectively minimized by short exposure times. The other methods described are effective for preventing more generalized blurring caused by voluntary motion. (Although breathing is mostly under autonomic control,respiration can normally be controlled temporarily by will, and is therefore considered a voluntary activity for the duration of a typical x-ray exposure.)

A lateral lumbar spine image was obtained with a field size of 11x14 inches at 95 kilovolts peak (kVp) and automatic exposure control (AEC) with the center detector selected. The resulting image demonstrates excessive quantum noise. Which is the most likely cause for this appearance? A. The field size was too large. B. The kVp was too high. C. The incorrect AEC detector was selected. D. The patient was not accurately centered.

d High levels of quantum noise result from too few photons striking the image receptor. In this instance, it is most likely that the lumbar spine was not positioned over the correct (center) detector, causing the surrounding soft tissues to be penetrated and the exposure to be terminated prematurely. With accurate positioning and correct AEC detector selection, a kVp of 95 should produce a quality lateral lumbar spine image. Although excessive scatter radiation increases image noise, a field size of 11 x14 inches should provide sufficient scatter control. Selection of the center detector is appropriate for this exam.