Maddie Physics :(

A radiograph is acquired using 450 milliamperes (mA) and an exposure time of 0.1 seconds (s). What new exposure time must be used to obtain the same receptor exposure if the radiograph is repeated with 300 mA? 0.044 s 0.15 s 0.23 s 0.66 s

0.15 s The receptor exposure will remain the same when the exposure time is changed to 0.15 seconds (s). This ensures that the new milliampere-seconds (mAs) is the same as the original mAs. Start by calculating the original mAs: 450 milliamperes (mA) x 0.1 s 45 mAs. Calculate the new mA by dividing the mAs by the new exposure time: 45 mAs/300 mA 0.15 seconds.

If the patient dose is 1 milligray (mGy) at a 40-inch (102 cm) source-to-image distance (SID), what is the patient dose at a 72-inch (183 cm) SID using the same technical factors? 0.3 mGy 0.55 mGy 1.8 mGy 3.25 mGy

0.3 mGy This question requires the use of the inverse square calculation. Start with the original patient dose 1), multiply by the original distance squared 40 ), and divide by the new distance squared 72 ). That's 1 40 / 72 0.3 µGy. Always check your math to make sure you squared the distances. The distance increased, so the new patient dose must decrease.

If the patient dose is 0.5 milligray (mGy) at a 50 inches (127 cm) source-to-skin distance (SSD), what is the patient dose at a 64 inch (162 cm) SSD using the same technical factors? 0.26 mGy 0.31 mGy 0.39 mGy 0.64 mGy

0.31 mGy This question requires the use of the inverse square calculation. Start with the original patient dose 0.5), multiply by the original distance squared 50 ), and divide by the new distance squared 64 ). That's 0.5 50 / 64 0.31 mGy. Always check your math to make sure you squared the distances. The distance increased, so the new patient dose must decrease.

How many shades of gray can one monitor pixel display at a time? 1 2 3 4

1 A pixel on a monitor can display only one shade of gray at a time

An exposure is produced with 20,000 heat units. What is the required anode cooling time? 0 minutes 1 minute 2 minutes 5 minutes

1 minute Draw a horizontal line from the 20,000 heat units until it connects with the curve. Draw a straight line down from that point to find the elapsed time. 20,000 HU would need 1 minute cooling time.

Radiographic grids are recommended when the anatomic part reaches which of the following thicknesses? 2 cm 4 cm 8 cm 10 cm

10 cm

How long would it take the anode to cool completely after using a 120,000 heat unit exposure? 4 minutes 8 minutes 10 minutes 14 minutes

10 min Drawing a line from 120 across to the curve, then straight down leads to 4 minutes. 14 minutes of total time minus 4 minutes equals 10 minutes to cool.

An x-ray exposure at 40 inches (102 cm) results in a beam intensity of 200 microgray (µGy). What is the new intensity for an x-ray exposure at 50 inches (127 cm)? 128 µGy 160 µGy 250 µGy 312 µGy

128 µGy This question requires the use of the inverse square calculation. The basic form of the inverse square calculation is (I1)/(I2)(D2 )/(D1 ). Another useful form of the calculation is (I2) I1) x (D1 )/(D2 ), which allows us to directly calculate the new intensity without any additional algebra or cross-multiplication. Start with the original intensity 200), multiply by the original distance squared 40 ), and divide by the new distance squared 50 ). That's 200 40 / 50 128 µGy. Always check your math to ensure you squared the distances. The distance increased, so the new intensity should decrease.

If an optimal radiograph is acquired at 72 inches (183 cm) with an air kerma of 4 milligray (mGy), what will the air kerma be if the distance is reduced to 40 inches (102 cm)? 1.23 mGy 4.6 mGy 7.2 mGy 13 mGy

13 mGy This question requires using the inverse square calculation. Start with the original air kerma 4), multiply by the original distance squared 72 ), and divide by the new distance squared 40 ). That's 4 72 / 40 13 mGy. Always check your math to make sure you squared the distances. The distance decreased, so the new air kerma should increase.

An image was taken resulting in the creation of 200,000 heat units HU. Approximately how long will it take the anode to cool down completely? 12 minutes 13 minutes 14 minutes 15 minutes

13 minutes After plotting 200,000 heat units HU on the cooling chart line and looking at the x-axis, it falls at 2 minutes. Since it takes 15 minutes to cool completely, simply take 15 - 2 13.

A radiograph is acquired using 200 milliamperes (mA) and an exposure time of 200 milliseconds (ms). What new exposure time must be used to obtain the same receptor exposure if the radiograph is repeated with 300 mA? 89 ms 133 ms 300 ms 450 ms

133 ms The receptor exposure will remain the same when the exposure time is changed to 133 milliseconds (ms). This ensures that the new milliampere-seconds (mAs) is the same as the original mAs. Start by converting the exposure time from milliseconds to seconds. The original exposure time is: 200 ms/1000 0.2 s. Next, calculate the original mAs: 200 mA x 0.2 s 40 mAs. Calculate the new exposure time by dividing the mAs by the new mA: 40 mAs/300 mA 0.133 seconds. Finally, convert the exposure time from seconds to milliseconds by multiplying by 1,000: 0.133 s x 1000 133 ms.

How long would it take the anode to cool completely after using a 240,000 heat unit HU exposure? 0 minutes 1 minute 13 minutes 14 minutes

14 min 240 is at the top of the curve, which means it will take a full 14 minutes for the anode to cool.

An image was taken resulting in 350,000 heat units HU. How long will it take for the anode to cool down completely? 8 minutes 13 minutes 15 minutes 18 minutes

15 minutes After plotting 350,000 heat units HU on the cooling chart line and looking at the X-axis, it falls at 0. Since it takes 15 minutes to cool completely, simply take 15 - 0 15.

How many heat units (HU) are created from a 20-second fluoroscopy study using a highfrequency x-ray machine set at 110 kilovoltage peak (kVp) and 5 milliamperes (mA)? 550 HU 797.5 HU 11,000 HU 15,950 HU

15,950 HU A 20-second fluoroscopy exposure using a high-frequency x-ray machine set at 110 kilovoltage peak (kVp) and 5 milliamperes (mA) produces 15,950 heat units (HU). This number is calculated by the formula kVp x mA x s x w. The waveform factor (w) for a high-frequency generator is 1.45. Therefore, the calculation is 110 x 5 x 20 x 1.45, which equals 15,950

What is the turns ratio for a transformer that has 50,000 turns on the primary side and 1,000 turns on the secondary side? 500:1 1:500 50:1 1:50

1:50 The turns ratio for a transformer that has 50,000 turns on the primary side and 1,000 turns on the secondary side is 150. The turns ratio is the ratio of secondary to primary turns, making this equation 100050,000, or 1000/50,000. Reducing this fraction gives an answer of 150.

Which of the following anode angles with the same size actual focal spot can tolerate the highest technical setting without overheating? 6 degrees 12 degrees 18 degrees 22 degrees

22 degrees A 22-degree anode can tolerate the highest technical settings without overheating. The largest anode angle creates the largest actual focal spot size and, as a result, the largest heat capacity. There is a direct relationship between anode angle and heat capacity - as the anode angle increases, the heat capacity of the anode also increases.

A radiograph acquired at 40 inches results in a receptor exposure of 10 milligray (mGy). What is the new receptor exposure if the radiograph is acquired with the same technical factors and 72 inches? 3.1 mGy 5.6 mGy 18 mGy 32.4 mGy

3.1 mGy (I1)/(I2)= (D1^2)/ )D2^2)

If the patient dose is 1 milligray (mGy) at a 72 inch (183 cm) source-to-image distance (SID),what is the patient dose at a 40 inch (102 cm) SID using the same technical factors? 0.3 mGy 0.55 mGy 1.8 mGy 3.24 mGy

3.24 mGy This question requires using the inverse square calculation. Start with the original patient dose 1), multiply by the original distance squared 72 ), and divide by the new distance squared 40 ). That's 1 72 / 40 3.24 µGy.

Which of the following monitors is the minimum size recommended by the American College of Radiography ACRfor routine radiography? 2MP (megapixel) 3MP (megapixel) 4MP (megapixel) 5MP (megapixel)

3MP (megapixel) The American College of Radiography (ACR) recommends a 3MP (megapixel) monitor for routine radiography. Mammography uses a minimum of 5MP.

How long would it take the anode to cool completely after using a 20,000 heat unit HU exposure? 2 minutes 4 minutes 10 minutes 20 minutes

4 min Drawing a line from 20 across to the curve, then straight down leads to 10 minutes. 14 minutes of total time minus 10 minutes equals 4 minutes to cool.

A patient has been brought to the imaging department for a radiograph of his knee. Previously,the patient had a portable knee exam completed in the emergency department (ED), using 70 kilovolts (kV), 2.5 milliampere-seconds (mAs), and a 61 grid. The exposure will be completed with the image receptor (IR) in the Bucky tray with a 121 grid. What new mAs will be required for the exposure in the department to compensate for the higher ratio grid? 1.5 mAs 4.16 mAs 7.5 mAs 12.6 mAs

4.16 mAs The exam should be completed with 4.0 mAs. According to the grid conversion formula, the correct calculation for this problem is (2.5 5) / 3 = 4.0. The original mAs is multiplied by the new grid conversion factor, and then that product is divided by the original grid conversion factor. Since the grid ratio is higher in the x-ray room, mAs must be increased in order to maintain an appropriate receptor exposure. The grid conversion formula is: (mAs1) / (mAs2) = (GF1) / (GF2). When all known variables are added to the formula, this becomes (2.5) / (x) = (3) / (5). Solving for (x), this becomes (x) = (2.5) x (5) / (3) = 4.16 mAs.

Consider this scenario: A transformer has 25,000 turns on the primary side and 5,000 turns on the secondary side. What is the voltage produced when 220 volts V are applied? 4.4 V 44 V 1,100 V 11,000 V

44 V In this scenario, the new voltage is 44 volts V. Based on the number of secondary turns compared to the number of primary turns, this is a step-down transformer, so we expect the new voltage to be decreased. The new voltage is calculated by multiplying the original voltage by the turns ratio. That is 220 5,000/25,000 44 V.

Which of the following anode angles with the same size actual focal spot can create a radiographic image demonstrating the highest spatial resolution? 6 degrees 12 degrees 18 degrees 22 degrees

6 degrees A 6-degree anode angle is capable of creating images with the highest spatial resolution. The smallest anode angle creates the smallest effective focal spot size and, as a result, the highest spatial resolution. The relationship between anode angle and spatial resolution is inverse - as the anode angle decreases, the spatial resolution increases.

A radiograph acquired at 60 kilovoltage peak (kVp) results in an underexposed image. What new kVp setting will double the receptor exposure? 51 kilovoltage peak (kVp) 57 kilovoltage peak (kVp) 63 kilovoltage peak (kVp) 69 kilovoltage peak (kVp)

69 kvp Changing the exposure technique from 60 kilovoltage peak (kVp) to 69 kVp will double the receptor exposure. This change is determined by the 15% rule, which states that increasing kVp by 15% will increase the receptor exposure by double. To calculate an increase in 15%, multiply the original kVp by 1.15. For this question, 60 1.15 69 kVp

An x-ray exposure measured at 60 inches (152 cm) results in a beam intensity of 100 microgray (µGy). What is the new intensity for an x-ray exposure at 72 inches (183 cm)? 69 µGy 83 µGy 120 µGy 144 µGy

69 µGy This question requires the use of the inverse square calculation. The basic form of the inverse square calculation is (I1)/(I2)(D2 )/(D1 ). Another useful form of the calculation is (I2) I1) x (D1 )/(D2 ), which allows us to directly calculate the new intensity without any additional algebra or cross-multiplication. Start with the original intensity 100), multiply by the original distance squared 60 ), and divide by the new distance squared 72 ). That's 100 60 / 72 69 µGy. Always check your math to ensure you squared the distances. The distance increased, so the new intensity should decrease

A grid that has lead strips with a height of 4 mm that are spaced 0.5 mm apart will have a grid ratio of: 2:1 4:1 8:1 16:1

8:1 This grid has a ratio of 81. Grid ratio is determined by dividing the height of lead strips by the distance between them. For the described grid, the ratio is calculated as 4/0.5 8, making the grid ratio 8:1.

An acute abdomen series is completed with three exposures acquired at 80 kilovoltage peak (kVp) and 30 milliampere-seconds (mAs) using a three-phase six-pulse machine. What is the total number of accumulated heat units (HU) for this series? 3,240 HU 7,200 HU 9,720 HU 10,440 HU

9,720 HU This series of exposures results in 9,720 heat units (HU). The HU for one exposure with these settings is calculated by the formula kVp x mAs x w. The waveform factor (w) for a three-phase six-pulse generator is 1.35. The calculation for one exposure is 80 30 1.35, which equals 3,240 HU. Since the series consists of three exposures, this number must be multiplied by three. Therefore, the calculation is 3,240 3, which equals 9,720 HU.

Within a transformer, electromagnetic induction is the process through which: A direct current is converted to an alternating current A fluctuating magnetic field creates an electric current An alternating current is converted to a direct current

A fluctuating magnetic field creates an electric current Electromagnetic induction is the process through which a magnetic field creates ("induces") current to flow. This occurs between the primary and secondary sides of a transformer. Alternating current on the primary side of the transformer creates a fluctuating magnetic field. This magnetic field interacts with the secondary coil of the transformer to create a new current. The new current will be higher or lower than the original current based on the turns ratio.

What is a radiographic histogram? The dimensions of the exposure field The number of pixels in the digital image A measure of patient exposure A graph of exposure frequencies

A graph of exposure frequencies A radiographic histogram is a graph of exposure frequencies detected by the image receptor. These raw exposure values are interpreted and manipulated by the computer system to create a high-quality digital radiograph ready for presentation. The other answer options are not correct. The dimensions of the exposure field is the field of view. The number of pixels in the digital image is the matrix size. The patient exposure is measured by various patient dose units and measurements that are not directly related to the histogram.

The source of x-ray emission within an x-ray tube is called the: Tungsten filament Cathode filament Effective focal spot Actual focal spot

Actual focal spot The actual focal spot is the source of x-ray emission within an x-ray tube. This is the physical area on the anode in which electron interactions create x-ray photons

The source of x-ray emission within an x-ray tube is called the: Tungsten filament Cathode filament Effective focal spot Actual focal spot

Actual focal spot size The actual focal spot is the source of x-ray emission within an x-ray tube. This is the physical area on the anode in which electron interactions create x-ray photons.

A portable anteroposterior AP radiograph of the chest demonstrates superimposition of the clavicles over the lung apices. How should this error be corrected? Adjust receptor position Adjust tube angulation Instruct patient to increase inhalation Instruct patient to elevate shoulders

Adjust tube angulation Superimposition of the clavicles over the lung apices should be corrected by adjusting the tube angulation. Increasing the caudal angle of the x-ray tube will ensure that the clavicles appear below the level of the lung apices. The other answer options are not correct. The receptor position does not need to be changed as the field of view is correct. Increasing inhalation and elevating the shoulders have minimal effect on the position of the clavicles.

When can a technologist reuse the computed radiography CR receptor after the appearance of a ghost image? After it's been cleaned After it's been thoroughly erased on a functioning CR reader Immediately, since the ghost image is gone After 24 hours of nonuse

After it's been thoroughly erased on a functioning CR reader Technologists can reuse a computed radiography CR receptor that had a ghost image as long as it's been thoroughly erased by a functioning CR reader. Cleaning the CR reader will not remove a ghost image, nor will waiting 24 hours, although those both may lessen the appearance of a ghost image. Technologists should definitely not reuse it immediately without thoroughly erasing it first.

The waveform of commercial power supply to the x-ray circuit is a(n): Direct current Alternating current Pulsed current

Alternating current The x-ray circuit is powered by an alternating current AC, as is all of the commercial power supply in the United States. The alternating current must be changed into a direct current to produce x-rays in the x-ray tube.

A transformer with a turns ratio of 401 will change amperage in which of the following ways? Amperage will increase Amperage will decrease Amperage will not be affected

Amperage will decrease The ratio 401 indicates this is a step-up transformer. There are 40 times more turns on the secondary side of the transformer compared to the primary side. Transformers are named according to their effect on the voltage, and the amperage does the reverse. A step-up transformer steps up (increases) the voltage, and the amperage decreases. A step-down transformer steps down (decreases) the voltage and the amperage increases

A technologist can identify an image produced with excessively high milliampere-seconds (mAs) based on which of the following? The appearance of quantum mottle The appearance of excessive image contrast The appearance of vertical streaks in the image An exposure indicator outside of the acceptable range

An exposure indicator outside of the acceptable range An image produced with excessively high milliampere-seconds (mAs) would be OVER-exposed. This would result in a receptor indicator outside of the acceptable range, and it may cause an artifact called saturation. Quantum mottle is the result of UNDER-exposure and would not be caused by a high mAs. Changes in mAs would not cause streaks or any change in contrast.

The Line-Focus Principle describes the geometric relationship between which of the following factors within an x-ray tube? Anode angle and the effective focal spot size Focusing cup voltage and x-ray energy spectrum Tube voltage and the x-ray energy spectrum Filament size and the actual focal spot size

Anode angle and the effective focal spot size The Line-Focus Principle describes the geometric relationship between the anode angle and the effective focal spot size. As the anode angle decreases, the effective focal spot size decreases

Which of the following projections would result in foreshortening of the anatomy being imaged? Cross-table lateral foot Axial plantodorsal calcaneus Anteroposterior AP elbow Anteroposterior AP lordotic chest

Anteroposterior AP lordotic chest For an anteroposterior AP lordotic chest radiograph, the patient is required to lean back against the upright image receptor, placing the thorax at an angle to the image receptor IR. The x-ray beam is directed perpendicularly to the receptor. Since the part is angled in relation to the beam and receptor, foreshortening of the thoracic cavity will result, with the lungs appearing much shorter than in a routine posteroanterior PA chest radiograph.

Which technologist mistake is most likely to cause processing errors within a computed radiography CR system? Incorrect focal spot selection Asymmetrical collimation Incorrect source-to-image distance SID Failure to include a radiographic marker

Asymmetrical collimation Asymmetrical collimation can cause processing errors in a computed radiography CR system. The exposure field should always be evenly collimated on 2 or 4 sides. While incorrect focal spot selection and source-to-image distance SID will affect the resolution, they would still be processed properly. Failure to include a radiographic marker will not result in a processing error.

During quality-control testing of the x-ray machine, the physicist observes that the actualkilovoltage peak (kVp) output does not match the prescribed kVp. Which component of the x-ray circuit may be responsible for this failure? Circuit breaker Autotransformer Kilovoltage peak (kVp) meter Exposure timer

Autotransformer Failure of the x-ray machine to produce the correct kilovoltage peak (kVp) may indicate a failure in the autotransformer. The autotransformer is an important component responsible for modifying the incoming line voltage to match the prescribed voltage set by the x-ray operator. The other components listed do not have any effect on the indicated or actual kVp. The kVp meter measures the output kVp, but it has no influence on setting the output kVp.

Which statement describes the relationship between kilovoltage peak (kVp) and beam intensity? Beam intensity is inversely proportional to the square of the kilovoltage peak (kVp) Beam intensity is directly proportional to the square of the kilovoltage peak (kVp) Beam intensity is inversely proportional to the kilovoltage peak (kVp) Beam intensity is directly proportional to the kilovoltage peak (kVp)

Beam intensity is directly proportional to the square of the kilovoltage peak (kVp) Beam intensity is directly proportional to the square of the kilovoltage peak (kVp). For example, if the kVp is increased by a factor of 2, the beam intensity increases by a factor 2 squared. This is why the kVp is usually changed in small increments.

An exposure is made using 100 milliamperes (mA) and 0.05 seconds (s). How will the beam intensity change if the exposure is repeated using 200 mA and 0.025 s? Beam intensity increases Beam intensity decreases Beam intensity remains the same

Beam intensity remains the same In this situation, the beam intensity remains the same. While the milliamperes (mA) have increased by double, the exposure time (s) has been reduced by half. When the total mAs is calculated for each exposure, the mAs is the same and therefore the beam intensity is also the same. 100 mA x 0.05 s 5 mAs. 200 mA x 0.025 s 5 mAs. The other answer options are not correct. The beam intensity increases when the mAs increases. The beam intensity decreases when the mAs decreases. There are other factors that significantly influence the beam intensity - such as kilovoltage peak (kVp) and filtration - but this question deals only with the mAs.

The anode heel effect is defined as a variation in which of the following? Patient thickness across the x-ray field Contrast resolution across the x-ray field Beam quality across the x-ray field Beam quantity across the x-ray field

Beam quantity across the x-ray field The anode heel effect is a variation in beam quantity (intensity) across the x-ray field. Some x-rays are absorbed in the heel of the anode, causing the anode side to be less intense and the cathode side to be more intense. Contrast resolution is determined by the x-ray system's hardware and software.

Which of the following tissues and materials corresponds to the highest signal intensity at theimage receptor? Liver Spleen Spine Bowel gas

Bowel gas Bowel gas corresponds to the highest signal intensity at the image receptor compared to the other answer options. Bowel gas is extremely low density, which means it attenuates very little radiation. As a result, most radiation-striking areas of bowel gas will pass through the gas and strike the image receptor. These areas where a significant amount of radiation transmits through the patient and strikes the image receptor are described as high signal intensity. The liver, spleen, and spine are denser, will attenuate more radiation, and result in a lower radiation signal intensity at the image receptor

In the following image, what pathology is indicated by distended loops of air-filled bowel and increased subject contrast throughout the abdomen? Bowel obstruction Ascites Pleural effusion Hepatic carcinoma

Bowel obstruction Bowel obstruction presents radiographically as distended loops of air-filled bowel and increased subject contrast throughout the abdomen. The other answer options are not correct. Ascites refers to excessive fluid accumulation in the abdomen, which results in decreased subject contrast. Hepatic carcinoma refers to liver cancer, which does not have a direct effect on the subject contrast within the abdomen. Pleural effusion is a condition of fluid accumulation in the pleural space around the lungs.

Which aspect of the x-ray circuit diagram includes the low-voltage portion of the step-up transformer? Circuit A Circuit B Circuit C

Circuit A Circuit A (red) represents the low-voltage-portion of the step-up transformer, commonly called the primary circuit. The entire x-ray circuit is three interconnected circuits that each make essential contributions to the process of x-ray production. Included in the diagram are the primary circuit (A), the secondary circuit (B), and the filament circuit (C).

Which aspect of the x-ray circuit diagram represents the secondary circuit of the x-ray system? Circuit A Circuit B Circuit C

Circuit B Circuit B (blue) represents the secondary circuit of the x-ray system. The secondary circuit may be referred to as the high-voltage portion of the circuit because the circuit voltage was converted from volts (V) to kilovolts (kV). Included in the diagram are the primary circuit (A), the secondary circuit (B), and the filament circuit (C).

The lowest exposure readings on a radiographic histogram usually represent areas of: Soft tissue Collimated exposure Unattenuated exposure Calcification

Collimated exposure The lowest exposure readings on a radiographic histogram usually represent the collimation. Very few x-ray photons penetrate the collimation, so the resulting exposure readings under the collimation are very low. These low exposure readings are excluded from the values of interest during histogram analysis.

Which of the following is the most important factor influencing the contrast of the radiographic image? Kilovoltage peak (kVp) Grid ratio Patient size (morphology) Computer processing

Computer processing Computer processing is the most important factor controlling the contrast of a radiographic image. kVp, grids, and patient size (morphology) all have a small effect on image contrast, but their influence is limited. Computer processing is extremely effective at creating radiographs with the ideal image contrast even when these other procedural factors are less than perfect.

The primary effect of scatter radiation on radiographic image quality is decreased: Receptor exposure Contrast Brightness Spatial resolution

Contrast Scatter radiation decreases image quality by decreasing contrast. Scatter radiation adds a layer of gray fog over the image and contributes no meaningful information to image formation. A grayer image is one with reduced, or lower, contrast. Receptor exposure is the amount of radiation hitting the Image Receptor, if scatter is present it will increase the total amount. Spatial Resolution would be affected by focal spot size, source-to-image distance SID, and object-to-image distance OID. Scatter does not have an effect on Spatial Resolution. Brightness is primarily controlled by pixel values and monitor luminance.

Which aspect of the x-ray circuit diagram represents the primary side of the step-down transformer? A B C D E

D Component D represents the primary side of the step-down transformer. The primary side always has more wire turns than the secondary side in a step-down transformer. This configuration decreases the voltage but increases the amperage. A is the autotransformer, B is the primary winding of the step-up transformer, C is the secondary winding of the step-up transformer, and E is the secondary winding of the step-down transformer.

In order to improve spatial resolution, a technologist should: Decrease source-to-image distance SID Increase object-to-image distance OID Increase focal spot size FSS Decrease focal spot size FSS

Decrease focal spot size FSS Decreased focal spot size FSS increases spatial resolution and decreases penumbra. By decreasing the source-to image distance SID, the photons are striking the edges of the object at more extreme angles and creating a larger area of penumbra and decreasing spatial resolution. Increasing object-to-image distance OID decreases spatial resolution by causing size distortion and penumbra.

The default technique for the lateral projection of the thoracic spine is 400 milliamperes (mA), 0.1 seconds (s), 80 kilovoltage peak (kVp), and 40 inches source-to-image distance (SID). How should the technologist modify this technique to blur the ribs and increase the visibility of the spine while maintaining the same receptor exposure? Increase mA and decrease exposure time Decrease mA and increase exposure time Increase mA and decrease kVp Decrease mA and increase kVp

Decrease mA and increase exposure time The technologist should decrease the milliamperes (mA) and increase the exposure time(s) in order to blur the ribs and increase visibility of the spine while maintaining the same receptor exposure. Increasing exposure time allows for the movement of the patient breathing to blur out the ribs on the radiograph. Since the exposure time is increased, there must be a corresponding decrease in the mA to ensure the total mAs is the same and the receptor exposure is the same

How does increasing window width affect the displayed image? Increased contrast Decreased contrast Increased sharpness Decreased sharpness

Decreased contrast Increasing window width results in decreased contrast. Window width is a post-processing setting that controls the displayed image contrast. Increasing window width expands the grayscale, creating more gray in the image, less black and white, and lower contrast. Window with has no effect on the sharpness or spatial resolution of the radiographic image.

What technical change is required to decrease receptor exposure when using automatic exposure control AEC? Increased milliamperage (mA) Decreased kilovoltage peak (kVp) Increased back-up timer Decreased density setting

Decreased density setting Decreasing the density setting is the primary way to decrease receptor exposure when using automatic exposure control (AEC). The design of the AEC system is to maintain the appropriate receptor exposure, even when variables such as the patient size, milliamperage (mA), and kilovoltage peak (kVp) are changed. Decreasing the density setting decreases the exposure level at which the system terminates the exposure. Changes to mA and kVp affect the exposure rate and the exposure time, but the total receptor exposure remains the same.

How does increased kilovoltage peak (kVp) affect differential attenuation of the x-ray beam? Increased differential attenuation Decreased differential attenuation kVp does not affect differential attenuation

Decreased differential attenuation Increased kilovoltage peak (kVp) results in decreased differential attenuation of the x-ray beam. In other words, a higher kVp results in more uniform penetration of the patient and more similar attenuation of the beam. As a result, the signal intensities striking the image receptor are all very similar which results in slightly lower image contrast. Fortunately, modern radiography equipment is very effective at creating ideal contrast even when the kVp is too high or too low.

Which effect will occur when using an automatic exposure control (AEC) system to image a hyposthenic (small body habitus) patient? Decreased spatial resolution Increased contrast resolution Increased receptor exposure Decreased exposure time

Decreased exposure time Imaging a hyposthenic patient with an automatic exposure control AEC system will result in a decreased exposure time. A hyposthenic patient is small or less robust. A high percentage of x-rays transmit through smaller patients, which allows the ideal receptor exposure in a shorter amount of time. The reverse would be true for larger patients. They absorb more radiation, resulting in less x-ray transmission and longer exposure time.

The use of an x-ray tube with a small anode angle results in which two of the following? Select two) Decreased heel effect Decreased focal spot size Increased focal spot size Decreased heat capacity

Decreased focal spot size, Decreased heat capacity A small anode angle results in decreased focal spot size, which decreases the heat capacity of the anode. This also results in more photons being absorbed in the anode and an increased anode heel effect.

A decrease in photon energy results in which of the following? Increased frequency and increased wavelength Decreased frequency and decreased wavelength Decreased frequency and increased wavelength Increased frequency and decreased wavelength

Decreased frequency and increased wavelength Photon frequency and photon energy are directly proportional, so as energy decreases, frequency decreases. However, photon frequency and photon wavelength are inversely proportional. As frequency decreases, wavelength increases.

What is the advantage of a focused grid as compared to a parallel grid? Increased image contrast Decreased grid cut-off Increased recorded detail Decreased distortion

Decreased grid cut-off There is less grid cut-off with the focused grid. There is less absorption of useful radiation by the grid because the lead strips are angled to match the divergence of the beam.

When using automatic exposure control AEC, which of the following technical changes will increase the total exposure time without increasing the receptor exposure? Decreased milliamperage (mA) Increased kilovoltage peak (kVp) Decreased back-up timer Increased density setting

Decreased milliamperage (mA) When using automatic exposure control (AEC, decreasing the milliamperage (mA will result in an increased exposure time. Decreasing the mA decreases the exposure RATE, so it takes more time to reach the desired exposure level at which the system terminates the exposure. Changes to mA affect the exposure RATE and the exposure TIME, but the total receptor exposure remains the same

Performing a radiograph of the clavicle in the posteroanterior PA position instead of anteroposterior AP will increase spatial resolution because of which of the following? It is more comfortable for the patient Increased object-to-image distance OID Increased source-to-image distance SID Decreased object-to-image distance OID

Decreased object-to-image distance OID Placing the anatomical part closer to the image receptor IR) decreases object-to-image distance OID). The clavicle sits more anterior in the thorax, so performing clavicle posteroanterior PA) will reduce OID. When OID is decreased, spatial resolution is increased. Source-to-image distance SID) will remain unchanged with PA and anteroposterior AP) clavicle projections; it will stay at 40 inches 102 cm) SID.

Increasing the source-to-image distance SID will result in which of the following? Increased quantity and increased quality of photons Decreased quantity and decreased quality of photons Increased quantity and will have no effect on the quality of photons Decreased quantity and will have no effect on the quality of photons

Decreased quantity and will have no effect on the quality of photons As distance increases, the quantity of photons decreases. Source-to-image distance SID has no effect on the quality of photons

An off-center grid error results in which of the following? Decreased receptor exposure on the outer edges of the radiograph Decreased receptor exposure across the entire radiograph Increased receptor exposure on the outer edges of the radiograph Increased receptor exposure across the entire radiograph

Decreased receptor exposure across the entire radiograph An off-center grid error results in decreased receptor exposure across the entire radiograph. Grids do not increase receptor exposure

An upside-down grid error results in which of the following? Increased receptor exposure on the outer edges of the radiograph Increased receptor exposure in the center of the radiograph Decreased receptor exposure in the center of the radiograph Decreased receptor exposure on the outer edges of the radiograph

Decreased receptor exposure on the outer edges of the radiograph An upside-down grid error results in decreased receptor exposure on the outer edges of the radiograph. The center of the radiograph would have acceptable exposure, not increased exposure.

What is the primary advantage of using a grid for a radiographic procedure? Reduced scatter production Increased recorded detail Decreased scatter reaching the image receptor Decreased image contrast

Decreased scatter reaching the image receptor Grids decrease the amount of scatter radiation reaching the image receptor. The function of the grid is to absorb the scatter radiation coming from the patient before it hits the receptor, therefore increasing image contrast. Because the grid is located behind the patient, it will not affect the amount of scatter produced

How do ascites affect the subject contrast of the abdomen? Increased subject contrast Decreased subject contrast No change in subject contrast

Decreased subject contrast Ascites results in decreased subject contrast. Ascites refer to the accumulation of excess fluid throughout the abdominal cavity. This excess fluid changes the attenuating properties of the abdomen such that there are decreased signal differences in the remnant beam. This ultimately corresponds to a decrease in the image contrast.

When the matrix size of a digital image decreases, the number of pixels within the image: Increases Decreases Remains the same

Decreases When the matrix size of a digital image decreases, the number of pixels within the image also decreases. The matrix size simply refers to the number of pixels within the image. For example, a 512 512 matrix is composed of 512 pixels within each row and each column of the image. An x-ray operator cannot change the matrix size of a digital image, but this is a factor that should be given consideration when purchasing new equipment.

What term describes the component of digital radiography receptors responsible for capturing the radiation signal transmitted through the patient? Picture element (pixel) Charge-coupled device Detector element (DEL) Photostimulable phosphor (PSP)

Detector element (DEL) The term detector element describes the individual components of a digital radiography receptor responsible for capturing the transmitted radiation. The other answer options are not correct. A charge-coupled device (CCD) is a light-collecting device commonly used in certain digital radiography systems. Photo-stimulable phosphors (PSP) are the active portion of computed radiography imaging plates. The term picture element (pixel) describes the smallest unit of information within a digital image. The term picture element (pixel) is also used to describe the light-emitting components within display monitors.

Which three of the following are factors that affect spatial resolution in digital radiography (DR)? (Select three) Milliampere-seconds (mAs) Detector element (DEL) size Detector element (DEL) pitch Exposure latitude Fill factor

Detector element (DEL) size Detector element (DEL) pitch Fill factor There are three factors in digital radiography (DR) that influence the spatial resolution of the radiographic image: Detector Element (DEL) size, DEL pitch, and fill factor. Technical factors such as milliampere-seconds (mAs) and kilovoltage peak (kVp) will not influence spatial resolution. Exposure latitude is a range of technical factors that produce quality images at an appropriate patient dose and has no influence on spatial resolution.

How is patient information added to a digital x-ray image? Digital annotation Digital Imaging and Communications in Medicine DICOM tag Directly typed into the notes Digitally scanned into the system

Digital Imaging and Communications in Medicine DICOM tag The patient's information is attached through a Digital Imaging and Communications in Medicine DICOM tag. Digital annotation is usually reserved for position marking. Additional information may be added through typing notes or digitally scanning information into the system.

To avoid damaging the x-ray tube components, the electrical power supplied to the x-ray tube must be: High voltage Low voltage Alternating current Direct current

Direct current The electrical power to the x-ray tube must be direct current DC in order to avoid damaging the x-ray tube. This ensures the electrons flow from cathode to the anode and not in reverse. Voltage is stepped up on the anode side of the tube and stepped down on the cathode side of the tube. If the tube received alternating current, the electrons would flow back and forth across the tube, damaging the cathode side, since the cathode is not designed to withstand electron bombardment.

Which of the following describes the detector element DEL pitch? Circumference of the DEL Height of the DEL Distance from one DEL to another Width of the DEL

Distance from one DEL to another Detector Element DEL pitch is simply the distance from one DEL to another.

Which of the following would double the quantity of photons in the x-ray beam? Select two) Double the time and double the milliamperage (mA simultaneously Double the exposure time, but do not change the milliamperage (mA Double the exposure time and cut the milliamperage (mA in half Double the milliamperage (mA, but do not change the exposure time

Double the exposure time, but do not change the milliamperage (mA Double the milliamperage (mA, but do not change the exposure time mA x s = mAs. Only one factor, mA or time (s), needs to be doubled to double the mAs, NOT both simultaneously. An example of this is 3 4 = 12. To double the total to 24, double either 3 or 4 to create an equation that looks like this: (3 2) x 4 = 24. If both 3 and 4 are doubled simultaneously, the total would be quadrupled: (3 2) x (4 2) = 48. Doubling time while cutting mA in half would result in no change to the mAs.

The area of the x-ray beam projected towards the patient is described as the: Tungsten filament Cathode filament Effective focal spot Actual focal spot

Effective focal spot The effective focal spot is the area of the x-ray beam directed towards the patient. The size of the effective focal spot is a critical factor in determining the spatial resolution of radiographic images. The actual focal spot is located at the anode within the x-ray tube.

Which of the following occurs when the anode angle decreases? Effective focal spot size decreases and the heel effect decreases Effective focal spot size decreases and the heel effect increases Effective focal spot size increases and the heel effect increases Effective focal spot size increases and the heel effect decreases

Effective focal spot size decreases and the heel effect increases As the anode angle decreases (example: from 20 degrees to 6 degrees), the effective focal spot size also decreases, but the anode heel effect increases.

A transformer operates on what principle? Magnetism Mechanical transformation Electromagnetic induction Electromechanical action

Electromagnetic induction A transformer operates on the principles of electromagnetic induction. There are no moving parts in a transformer. Instead, a fluctuating magnetic field is used to induce a new electrical current that has a different voltage than the original. The other answer options are not correct. Mechanical transformation and electromechanical action both imply moving parts ("mechanical"), and a transformer has no moving parts. A transformer does use magnetism, but magnetism by itself is not the operating principle

Which of the following is used to create the patient's requisition? Hospital Information System HIS Radiology Information System RIS Electronic Medical Record EM Medical Image Management and Processing Systems MIMPS

Electronic Medical Record EM The Electronic Medical Record EMR is used to create the requisition that will populate the examination information with the patient's name, date of birth, location, and other relevant information. The Radiology information system is used for ordering and reporting. The hospital information system blends patient information, reporting, and billing. Medical Image Management and Processing Systems MIMPS comprises systems for image display, archiving, networking, and storage.

Exposure time is the amount of time that: Electrons are flowing through the filament Electrons are flowing through the x-ray tube Is required for photons to travel from the x-ray tube to the patient Is required for photons to dissipate in the examination room

Electrons are flowing through the x-ray tube Exposure time refers to the amount of time electrons are flowing through the x-ray tube. It can also be defined as the amount of time that x-rays are being created.

Shape distortion includes which specific types of distortion? Magnification and minification Magnification, elongation, and foreshortening Elongation and foreshortening Foreshortening and compression

Elongation and foreshortening Shape distortion is described as a misrepresentation of the shape of the anatomy being imaged, and the two possible forms are described as elongation and foreshortening. Elongation would result in an image appearing longer than normal size. Foreshortening would result in an image shorter than normal size. Size distortion includes magnification and minification.

Which of the following information is required to be included in Digital Imaging and Communications in Medicine DICOM images? Patient dose Exam location (facility) Labeled anatomy Radiologist's initials

Exam location (facility) The facility where the exam was performed must be among the information included with the images. The patient dose is not required by law to be included, nor must any anatomy be labeled. While the radiologic technologist that performed the exam must include their initials on the image, the radiologist that reads the exam does not need to include their initials on the image.

When reviewing the radiographic exposure indicator, what does an "S" (sensitivity) number significantly below 200 indicate? Insufficient image contrast Excessive image contrast Insufficient receptor exposure Excessive receptor exposure

Excessive receptor exposure An "S" (sensitivity) number significantly below 200 indicates excessive receptor exposure, meaning the receptor was over-exposed. The S number system is inverse - a low S number indicates a high exposure, and a high S number indicates a low exposure. The ideal S number is 200. The S number is not an evaluation of image contrast.

Which type of shape distortion is represented in the following illustration? Elongation Foreshortening Moire pattern Minification

Foreshortening When the anatomical part is angled, but the x-ray beam is directed perpendicularly to the receptor, foreshortening of the object being imaged will result. In this illustration, foreshortening is evident by the projected shadow, which is shorter than the actual object. The Moire pattern is a wave-like artifact.

What type of rectification occurs when the negative voltage peak is inverted to positive voltage? Half-wave rectification Full-wave rectification Non-rectification

Full-wave rectification A waveform with full-wave rectification is identified as having negative voltage peaks inverted to positive voltage. This ensures that all electrons flow in the same direction within the waveform. This is different from half-wave rectification in that half-wave rectification only blocks (but does not invert) the reversing electron flow. A waveform with half-wave rectification is identified as having large gaps in which the negative voltage was blocked but NOT inverted to positive voltage.

Which of the following describes the contrast and brightness calibration of the display monitor? Exposure recognition Window width WW Grayscale standard display function GSDF Automatic brightness control ABC

Grayscale standard display function GSDF Grayscale standard display function GSDF describes the contrast and brightness calibration of the display monitor. This defines how the monitor should respond to the exposure values in the image, ensuring that the same radiographic image displays with the same contrast and brightness on any PACS/MIMPS monitor. The other answer options are not correct. exposure recognition is another term for histogram analysis. Window width WW is a postprocessing feature that controls the contrast of the displayed image. Automatic brightness control ABC is a device used in fluoroscopic imaging to automatically adjust the mA and/or kVp to maintain adequate receptor exposure.

Compared to a stationary grid, the main advantage of using a moving grid is that the: Grid lines will be more visible with a moving grid Grid lines will be blurred and not visible with a moving grid Moving grid is more efficient at absorbing scatter radiation Moving grid will produce higher contrast images

Grid lines will be blurred and not visible with a moving grid Gridlines are blurred and not visible with a moving grid. By creating the movement of the grid in the table or upright Bucky, grid lines become blurred and are not visible in the image. A stationary grid may not be moved during the exposure so that grid lines may be visible on the image. The movement of the grid does not change the efficiency of the grid at absorbing scatter radiation.

The height of the lead strips within a radiographic grid compared to the distance between them is described as the: Grid conversion Grid frequency Grid ratio Grid efficiency

Grid ratio The grid ratio is the height of the lead strip compared to the width, or distance, between them. This is calculated by dividing the height H of the lead strips by the distance D between the strips: H/D. Grid ratio is directly related to the efficiency of a grid.

A waveform with large gaps between positive voltage peaks is a result of which of the following? Full-wave rectification Half-wave rectification Non-rectification

Half-wave rectification A waveform with large gaps between positive voltage peaks is a result of half-wave rectification. Half-wave rectification is caused by the elimination of the negative, or reversed, pulse of the current flow in an electrical cycle. This is called "half-wave" rectification because only half of the wave is preserved during the rectification process. This leaves large gaps between each voltage pulse. During these gaps, there is no x-ray production occurring

The term "tube loading" refers to which of the following? X-ray intensity created within the x-ray tube Electron quantity produced within the x-ray tube Heat energy created in the x-ray tube Leakage radiation escaping the x-ray tube

Heat energy created in the x-ray tube Tube loading refers to the heat created in the x-ray tube, especially at the anode. X-ray production processes create a tremendous amount of heat within the anode, which can lead to tube damage. Tube loading is a significant consideration in the construction and use of x-ray tubes.The electron quantity and intensity created within the tube would have an effect on the heat energy created, but neither by itself is known as "tube loading". Leakage radiation is the radiation that escapes from the tube housing, but also is not "tube loading"

Large signal differences in the remnant beam will produce a radiographic image demonstrating: High spatial resolution Low spatial resolution High image contrast Low image contrast

High image contrast High image contrast is produced from large signal differences in the remnant beam. Low signal intensity corresponds to areas that experienced a high level of attenuation, such as bone, and are displayed with brighter shades of gray. High signal intensity corresponds to areas that experience a low level of attenuation, such as air, and are displayed with darker shades of gray. When the remnant beam has large differences in signal intensity, this generally corresponds to large differences in brightness levels, which is higher image contrast.

The large difference in signal intensities within the remnant beam of a chest exposure is described as: Low subject contrast High subject contrast Low receptor exposure High receptor exposure

High subject contrast High subject contrast is the correct terminology to describe the large difference in signal intensities within the remnant beam of a chest exposure. The other answer options are not correct. Receptor exposure refers to the total amount of radiation striking the image receptor, not the difference in signal intensities within the remnant beam.

What term describes a body section which creates a remnant beam having widely varying signal intensities? High spatial resolution Low spatial resolution High subject contrast Low subject contrast

High subject contrast High subject contrast is the terminology used to describe a body section that creates a remnant beam having a widely varying signal intensity. High subject contrast generally corresponds to high image contrast in the radiographic image. The other answer options are not correct. The spatial resolution refers to the sharpness of structural edges recorded in the radiographic image. Spatial resolution is not affected by variations in the signal intensity in the remnant beam.

In the x-ray circuit diagram, the electrical power at component C is described as: Low-voltage alternating current AC Low-voltage direct current DC High-voltage alternating current AC High-voltage direct current DC

High-voltage alternating current AC The electrical power at component (C is a high-voltage alternating current. Component (C is the high-voltage side of the step-up transformer, which means the electrical power has converted from volts (V to kilovolts (kV. This is BEFORE the rectifiers, and the waveform is still alternating current. Component (A represents the autotransformer where small changes are made to the incoming voltage. Component (B represents the primary side of the step-up transformer where the power is still low voltage. Component (D represents a rectifier bridge where the current is converted from alternating current into direct current. Component (E represents the x-ray tube where electrons are converted into x-rays.

Which of the following is an image processing factor that influences radiographic image contrast? Window width Histogram analysis Grayscale standard display function GSDF Shuttering

Histogram analysis Histogram analysis is an image processing factor that influences radiographic image contrast. Histogram analysis (exposure recognition) is an automatic computer process that evaluates the raw histogram and identifies the values of interest (VOI). This process ensures that only the patient's anatomy is included in the grayscale of the image. Other areas, such as the collimation and raw exposure outside of the body part, are not included in the grayscale. The other answer options are not correct. Window width (WW) and grayscale standard display function (GSDF) influence contrast, but they are not part of image processing. Window width (WW) is a post-processing feature that controls the contrast of the displayed image. The Grayscale standard display function (GSDF) defines how the monitor should respond to the exposure values in the image. Shuttering is a post-processing tool used to cover areas of collimation.

What is the process called that identifies the values of interest in a radiographic histogram? Histogram analysis Rescaling Lookup table LUT conversion Post-processing

Histogram analysis Histogram analysis is the process through which the values of interest are identified. Rescaling is the process by which the computer modifies the actual histogram to the expected histogram. The Lookup Table (LUT) is used to adjust pixel values to the proper contrast and brightness. Post-processing is changes made to the image after the computer has processed it (such as window leveling, annotation, etc.).

Which of the following terms describes a computer processing feature that influences radiographic image contrast? Select two) Histogram analysis Lookup table LUT Window width Grayscale standard display function GSDF

Histogram analysis, Lookup table LUT Histogram analysis and lookup tables LUT are computer processing features that influence image contrast. The other answer options are not correct. The window width does influence image contrast, but this is a post-processing feature available at the PACS or MIMPS display monitor. Grayscale standard display function GSDF also influences the displayed image contrast, but this is a feature of the display monitor, not a computer process.

Pixel malfunction within a digital radiography DR image receptor IR is likely to manifest on a radiograph as: Loss of contrast Hyperdense artifact Loss of spatial resolution Geometric distortion

Hyperdense artifact Pixel malfunction manifests as hyper-dense, or bright white, on the radiograph. A global loss of contrast is caused by radiation fog, or scatter. A loss of spatial resolution is also known as "blur", and is caused by one of the geometric factors, such as excessive object-to-image distance OID. Geometric distortions are foreshortening and elongation of anatomy.

When performing an abdomen radiograph, which body habitus would result in the largest objectto-image Distance OID? Asthenic body habitus (small patient) Sthenic body habitus (average patient) Hypersthenic body habitus (large patient) All body habitus will have the same OID

Hypersthenic body habitus (large patient) A hypersthenic patient is a larger patient which creates a larger object-to-image distance OID. Hypersthenic patients have more body mass creating a larger distance between anatomical structures and the image receptor IR. Asthenic patients are smaller and the abdomen will have a decreased OID. Sthenic patients are considered average patients and would not have as much body mass as hypersthenic patients.

Foreshortening of the femoral neck in this anteroposterior AP radiograph of the hip is caused by: Incomplete external rotation of the left leg Incomplete inversion of the left leg Incorrect receptor placement Incorrect tube angulation

Incomplete inversion of the left leg Foreshortening of the femoral neck in this anteroposteriorAP radiograph of the hip is caused by incomplete inversion of the left leg. This error causes the femoral neck to be superimposed on itself, making the anatomy appear shorter than it actually is. This issue affects the diagnostic quality of the examination and should be corrected by repeating the exposure after internally rotating the leg.

Which grid error results in grid cut-off and loss of exposure on the outside edges of the image receptor? Upside down non-focused grid Incorrect angulation of the beam across lead strips Off-level, or tilted grid error Incorrect source-to-image distance SID with a focused grid

Incorrect source-to-image distance SID with a focused grid Using an incorrect source-to-image distance SID with a focused grid will result in grid cut-off and loss of exposure on the outside edges of the image receptor. This is also called an off-focus grid error. Focused grids are designed to be used with specific SID ranges as specified by the manufacturers. Grid cut-off will occur more at the outer edges of the grid when the SID is outside of this range, resulting in loss of exposure to the image receptor in those areas.

Consider a transformer that has 10 times more turns on the secondary side than on the primary side. How will this transformer change the voltage? Increase by 10 Decrease by 10 Increase by a factor of 10 Decrease by a factor of 10

Increase by a factor of 10 The transformer described is a step-up transformer. The step-up transformer with 10 times more wire turns on the secondary side will increase voltage by a factor 10 (multiply by 10.

A radiograph of the lumbar spine is produced using automatic exposure control AEC. The exposure results in optimal contrast but low receptor exposure. What is the ideal way to increase receptor exposure? Increase milliamperage (mA) Increase kilovoltage peak (kVp) Decrease grid ratio Increase density setting

Increase density setting Increasing the density setting is the primary way to increase receptor exposure when using automatic exposure control (AEC). This is because increasing the density setting increases the exposure level at which the system terminates the exposure. Increasing the milliamperage (mA) or kilovoltage peak (kVp) will increase the exposure RATE and shorten the exposure TIME, but the receptor exposure will remain the same. Avoid changing the kVp because kVp is a key factor influencing image contrast.

Step-up transformers affect voltage and amperage in which of the following ways? Increase voltage and amperage Increase voltage and decrease amperage Decrease voltage and amperage Increase amperage and decrease voltage

Increase voltage and decrease amperage The function of a step-up transformer is to increase voltage and decrease amperage within the x-ray circuit. Transformers are named according to how they change the voltage. A step-up transformer increases voltage and step-down transformer decreases voltage

In an extreme case of off-focus grid error, which of the following may result? Decreased brightness and quantum mottle at the edges of the image Decreased brightness and quantum mottle at the center of the image Increased brightness and quantum mottle at the edges of the image Increased brightness and quantum mottle at the center of the image

Increased brightness and quantum mottle at the edges of the image Extreme case of off-focus grid error may result in increased brightness and quantum mottle at the edges of the image.

How does an increased grid ratio affect radiographic image contrast? Decreased contrast Increased contrast Grid ratio does not affect image contrast

Increased contrast Increased grid ratio results in increased contrast. Radiographic grids preferentially remove scatter radiation from the remnant beam. The reduction of scatter increases the signal differences striking the image receptor, which in turn becomes increased contrast in the processed image. Modern radiography computer processing is very effective at creating ideal image contrast, but the use of radiographic grids is still useful for removing scatter and improving contrast.

Increasing the tube current applied to the x-ray tube results in: Increased electron flow and increased x-ray quality Decreased electron flow and increased x-ray quality Decreased electron flow and decreased x-ray quantity Increased electron flow and increased x-ray quantity

Increased electron flow and increased x-ray quantity Increasing tube current results in increased electron flow and increased x-ray quantity. Tube current refers to the milliamperage (mA) setting. Increasing tube current (mA) increases the number of electrons flowing through the tube and increases the number of x-ray photons created at the anode. There is no change in the average photon energy (quality).

A technologist is performing an anteroposterior (AP) abdomen radiograph on a geriatric patient using an automatic exposure control (AEC) system. Which of the following changes will be noted if the technologist decreases the kilovoltage peak (kVp)? Decreased patient dose Increased receptor exposure Decreased contrast Increased exposure time

Increased exposure time When using automatic exposure control (AEC), decreasing the kilovoltage peak (kVp) will result in increased exposure time; decreasing the kVp results in fewer photons in the beam and less penetrating ability. By decreasing the exposure RATE, it takes more time to reach the desired exposure level at which the system terminates the exposure. Changes to milliamperage (mA) and kVp affect the exposure RATE and the exposure TIME, but the total receptor exposure remains the same.

The use of an x-ray tube with a large anode angle results in which two of the following? Selecttwo) Increased heel effect Increased focal spot size Increased heat capacity Decreased heat capacity

Increased focal spot size Increased heat capacity A large anode angle results in increased focal spot size, which increases the heat capacity of the anode. This also results in fewer photons being absorbed in the anode and a decreased anode heel effect.

What is the principal advantage of using the large filament within a dual focus x-ray tube? Decreased image distortion Increased image contrast Increased heat capacity Increased spatial resolution

Increased heat capacity The principal advantage of using the large filament is increased heat capacity. The large filament spreads out the electron beam over a larger area on the anode. Distributing the heat over a larger area allows the x-ray tube to tolerate larger exposures without the risk of overheating the cathode or anode.

How does an air-filled bowel obstruction affect the subject contrast of the abdomen? Increased subject contrast Decreased subject contrast No change in subject contrast

Increased subject contrast An air-filled bowel obstruction results in increased subject contrast. Air within the bowels changes the attenuating properties of the tissues such that there are greater signal differences in the remnant beam. This ultimately corresponds to an increase in image contrast.

Consider an x-ray examination that uses these technical factors: 300 milliamperes (mA), 100 milliseconds (ms), 75 kilovoltage peak (kVp), and 72 inch (183 cm) source-to-distance (SID). Changing the SID to 40 inches (102 cm) will result in which of the following? Increased x-ray beam energy Increased x-ray beam intensity Decreased x-ray beam energy Decreased x-ray beam intensity

Increased x-ray beam intensity Decreasing the source-to-image distance (SID) from 72 inches (183 cm) to 40 inches (102 cm) will result in an increased x-ray beam intensity. Moving the x-ray tube closer to the receptor results in a more concentrated x-ray beam, which is described as an increase in intensity (quantity). Decreasing distance increases intensity. This relationship is governed by the inverse square law.

What is the relationship between technical factors and the Sensitivity (S number) indicator used on some computed radiography CR) equipment? There is no relationship Relationship is influenced by the 15% rule Direct relationship Indirect relationship

Indirect relationship There is an indirect relationship between technical factors and the S number with Fuji. A low S number indicates an overexposure and a high S number indicates underexposure. The ideal S number with Fuji is 200. Exposures falling well below 200 (example- 75 indicate that the technical factors were too high for the anatomical part.

When reviewing the radiographic exposure indicator, what does an "S" (sensitivity) number significantly above 200 indicate? Insufficient image contrast Excessive image contrast Insufficient receptor exposure Excessive receptor exposure

Insufficient receptor exposure An "S" (sensitivity) number significantly above 200 indicates insufficient receptor exposure, meaning the receptor was under-exposed. The S number system is inverse - a low S number indicates a high exposure, and a high S number indicates a low exposure. The ideal S number is 200. The S number is not an evaluation of image contrast.

What characteristic of the x-ray beam is influenced by changes to the source-to-image distance SID? Average energy Intensity Penetrability Quality

Intensity The beam intensity (quantity) is influenced by changes to the source-to-image distance (SID). The specific relationship is defined according to the inverse square law. Average energy, penetrability, and quality all refer to the energy of the x-ray beam. The energy of the x-ray beam does not change as the distance from the source changes.

How can a technologist correct an image of an anteroposterior AP hip that demonstrates foreshortening of the femoral neck? Externally rotate the leg and repeat the exposure Increase tube angulation and repeat the exposure Internally rotate the leg and repeat the exposure Decrease tube angulation and repeat the exposure

Internally rotate the leg and repeat the exposure Foreshortening of the femoral neck during AP imaging of the hip should be corrected by internally rotating the leg and repeating the exposure. Foreshortening of the femoral neck affects the diagnostic quality of the examination. This is an error that should be corrected before the image is submitted to the radiologist for interpretation.

What component within the automatic exposure control AEC system measures the quantity of photons exiting the patient? Rectifier bridge Autotransformer Ionization chamber Exposure timer

Ionization chamber An automatic exposure control (AEC) system includes three or more ionization chambers that measure the quantity of photons exiting the patient and striking the image receptor. When the ionization chamber(s) has detected the ideal receptor exposure, a signal is sent to the exposure timer to terminate the exposure. The Autotransformer is located in the x-ray circuit and is the location of kVp selection. The rectifier is located in the x-ray circuit and will change alternating current to direct current. The exposure timer is located within the x-ray circuit.

The basic construction of an autotransformer within the x-ray circuit includes which of the following? Air core and single wire coil Air core and double wire coil Iron core and double wire coil Iron core and single wire coil

Iron core and single wire coil An autotransformer within the x-ray circuit is composed of an iron core and a single wire coil. The single-wire coil serves as both the primary and secondary coil. The autotransformer induces a voltage change in itself (selfinduction) based on the turns ratio between the primary and secondary portions of the coil.

When using automatic exposure control AEC), the technologist can directly assign which three of the following parameters? Select three) Kilovoltage peak (kVp) Milliampere-seconds (mAs) Source-to-image distance (SID) Object-to-image distance (OID)

Kilovoltage peak (kVp), Source-to-image distance (SID), Object-to-image distance (OID) The technologist can directly assign kilovoltage potential (kVp), source-to-image distance (SID), and object-to-image distance (OID). The technologist cannot directly assign the milliampere-seconds (mAs) when using an automatic exposure control (AEC) system. Additionally, the AEC system controls the exposure time in seconds (s). As a result, the total mAs is not defined until the AEC system terminates the exposure.

In this lateral radiograph of the knee, the appearance of one femoral condyle posterior to the other condyle should be corrected by adjusting the: flexion of the knee X-ray tube angulation Lateral rotation of the knee Receptor exposure

Lateral rotation of the knee The appearance of one femoral condyle posterior to the other condyle should be corrected by adjusting the lateral rotation of the knee. When there is a lack of superimposition front-to-back, this indicates the knee position should be changed. The other answer options are not correct. Flexion of the knee, x-ray tube angulation, and receptor position do not affect front-to-back superimposition

Which of the following projections may be improved by using a low-milliampere (mA, longexposure time technique? Lateral thoracic spine Supine abdomen Decubitus chest Anteroposterior AP axial cranium

Lateral thoracic spine The lateral thoracic spine projection may be improved by using a low-milliampere (mA), long-exposure time technique, known as a "breathing technique". The exposure time is increased and the patient is instructed to breathe gently during the exposure. Breathing causes the ribs to appear blurred in the image, which increases the visibility of the underlying thoracic spine. When the exposure time is increased, the mA must be decreased by the same proportion to maintain the same total milliampere-seconds (mAs) and the same total receptor exposure.

Which of the following materials can't be used as interspace material inside a radiographic grid? Aluminum Lead Plastic Carbon fiber

Lead Radiographic grids are constructed using lead strips alternating with radiolucent material that allows the x-ray beam to transmit through. The interspace material is located between the lead lines. Aluminum, plastic, or carbon fibers are all considered radiolucent materials and will allow the x-ray beam to transmit through. Lead can't be used as an interspace material, it will absorb or block the x-ray photons from transmitting through the grid.

Which two of the following identifiers are required by law to be included on a radiographic image? Select two) Technologist initials or identification number Location of the examination Right or left marker Referring physician's name

Location of the examination, Right or left marker A radiographic image must include the location of the examination and a right or left marker, as well as the patient's name, date of birth, and the date the exam was performed. The technologist's initials are not required by law.

Low contrast is defined by: Short gray-scale and many shades of gray Long gray-scale and many shades of gray Short gray-scale and few shades of gray Long gray-scale and few shades of gray

Long gray-scale and many shades of gray A radiographic image that contains many shades of gray would be referred to as having low contrast. Remember, low contrast means that there are many shades of gray and very little black and white in the radiograph. The term "long gray-scale" refers to the presence of many different shades of gray.

Which of the following might make it difficult to visualize the anatomy and pathology of the abdomen? Short gray-scale and many shades of gray Short gray-scale and few shades of gray Long gray-scale and few shades of gray Long gray-scale and many shades of gray

Long gray-scale and many shades of gray The tissues of the abdominal cavity are of similar nature and density. In order to visualize the differences between these adjacent tissues, the radiograph needs to have high contrast and a short gray-scale. Having a long gray-scale and many shades of gray would make it more difficult to image these similar tissue types

The highest quality radiograph would be produced by which of the following situations? Longer source-to-image distance SID and shorter object-to-image distance OID Longer source-to-image distance SID and longer object-to-image distance OID Shorter source-to-image distance SID and shorter object-to-image distance OID Shorter source-to-image distance SID and longer object-to-image distance OID

Longer source-to-image distance SID and shorter object-to-image distance OID The best situation to reduce magnification is the use of a longer source-to-image distance SID and a shorter objectto-image distance OID, placing the part as close to the image receptor as possible. Image quality is improved when magnification is reduced.

What term describes the mathematical filter that increases contrast within a radiographic image? Automatic brightness control (ABC) Histogram analysis Edge enhancement Lookup table LUT

Lookup table LUT The lookup table LUT is a mathematical filter that increases the inherent contrast within a radiographic image. The LUT Is necessary because the raw, unprocessed exposure values have very low contrast. The other answer options are not correct. Histogram analysis is the process through which the computer system identifies the values of interest VOI. This process ensures that only the patient's anatomy is included in the grayscale of the image. Automatic brightness control ABC is a device used in fluoroscopic imaging to automatically adjust the mA and/or kVp to maintain adequate receptor exposure. Edge enhancement is a process that adds sharpness to the image.

Which term best describes the process of adding brightness and contrast to exposure values within a radiographic image? Histogram analysis Rescaling Lookup table LUT conversion Post-processing

Lookup table LUT conversion The Lookup Table (LUT) is used to adjust pixel values to the proper contrast and brightness. Histogram analysis is the process through which the values of interest are identified. Rescaling is the process by which the computer modifies the actual histogram to the expected histogram. Post-processing is changes made to the image after the computer has processed it (such as window leveling, annotation, etc.).

Which of the following can also be referred to as size distortion? Elongation Magnification Foreshortening Pixelation

Magnification Size distortion is a misrepresentation of the true size of the object being imaged, and is always described as magnification. Due to the physics of the x-ray beam and its interaction with anatomy and image receptor IR, the object cannot be recorded as smaller than it actually is.

Subject contrast in radiography refers to the: Range of exposures that can be captured by a detector Magnitude of signal difference in the remnant beam Total number of brightness levels available in radiography computer system Range of brightness levels that can be produced by the display monitor

Magnitude of signal difference in the remnant beam Subject contrast in radiography refers to the magnitude of signal difference in the remnant beam. This is controlled by the absorption characteristics of the tissues and structures being exposed. Highly attenuating tissues result in a lower signal in that part of the beam. Minimally attenuating tissues result in a higher signal in that part of the beam. The difference in signal is the subject contrast. The other answer options are not correct. The range of exposures that can be captured by a detector is called the dynamic range. The number of brightness levels available in a radiography computer system is called the bit depth. The range of brightness levels that can be produced by the display monitor is also called bit depth.

The autotransformer is located within the x-ray circuit between the: Step-up transformer and the x-ray tube Step-down transformer and filament Rectifier bridge and the x-ray tube Main power supply and the step-up transformer

Main power supply and the step-up transformer The autotransformer is located between the main power supply and the step-up transformer. The autotransformer and the step-up transformer work together to convert the incoming power supply (220 V) to the exact kilovoltage peak (kVp) assigned by the technologist.

What technical factor controls the temperature of the cathode filament within the x-ray tube? Inherent filtration Kilovoltage peak (kVp) Exposure time (s) Milliamperage (mA)

Milliamperage (mA) Milliamperage (mA controls the temperature of the cathode filament. Increasing mA results in more current and more heat within the cathode. Inherent filtration hardens the beam, kVp controls the electric potential difference, and the exposure time controls how long the exposure lasts.

Failure of the rheostat within the x-ray circuit would result in the inability to: Supply adequate voltage to the x-ray tube Modify the filament current Modify the exposure time Supply direct current to the x-ray tube

Modify the filament current Failure of the rheostat would result in the inability to modify the filament current. The filament current (mA) is directly controlled by the technologist through the rheostat (mA selector). The filament circuit does not provide voltage or direct current to the x-ray tube. The rheostat selects the mA, not the exposure time

Directing the anode side of the x-ray field towards the toes during an anteroposterior AP projection of the foot results in which of the following? More uniform spatial resolution More uniform receptor exposure Lower contrast resolution Lower signal-to-noise ratio SNR

More uniform receptor exposure This question describes the correct use of the anode heel effect, resulting in more uniform receptor exposure. The anode side of the x-ray beam is less intense and should be directed toward the least dense portion of the part being imaged (the toes). The cathode side is more intense and should be directed toward the denser portion of the part being imaged (the ankle). The anode heel effect causes non-uniform spatial resolution, with a smaller effective focal spot on the anode side. The signal-to-noise ratio (SNR) is unaffected by the anode heel effect. Contrast resolution is determined by the x-ray system's hardware and software.

A technologist is using a variable kilovoltage peak (kVp) chart to set the exposure technique for a table-top radiograph. If the technique chart calls for 87 kVp but the technologist uses 82 kVp, the resulting image will likely demonstrate which of the following? Saturation artifact Quantum mottle Increased contrast No visible errors

No visible errors Using 82 kilovoltage peak (kVp) rather than 87 kVp will result in no visible errors. Under-exposure artifact, called quantum mottle, only occurs when the receptor exposure is significantly less than desired. Over-exposure artifact, called saturation, occurs only when the exposure technique is several times more than necessary. Increasing kVp from 82 to 87 is not a large enough change in kVp to significantly change the scale of subject contrast. Increasing kVp will also decrease subject contrast.

The term "phase" in an x-ray circuit refers to the: Direction of current flow within the circuit Amplitude of waves within the circuit Number of wave cycles per second in the circuit Number of distinct waveforms in the circuit

Number of distinct waveforms in the circuit The term "phase" refers to the number of distinct waveforms in the circuit. Single-phase has just one wave, and three-phase has three separate waveforms within the circuit. The number of phases affects the number of pulses, frequency, energy, and intensity of the x-ray beam. The number of wave cycles per second is the frequency and is measured in Hertz. The amplitude of waves is the height of the wave, also known as the intensity. Electrons travel from negative to positive.

The turns ratio of a transformer is described as which of the following? Number of primary coils to the number of secondary coils Number of secondary coils to the number of primary coils Strength of the primary magnetic field to the strength of the secondary field

Number of secondary coils to the number of primary coils The ratio of the number of secondary coils to primary coils describes the turns ratio. The difference between these coils is what determines the voltage change. If there are more turns on the secondary side the voltage will increase. If there are more turns on the primary side the voltage will decrease.

Turns ratio of a transformer is defined as the ratio of which of the following? Current to the voltage in the primary coil Current to the voltage in the secondary coil Number of primary turns to the number of secondary turns Number of secondary turns to the number of primary turns

Number of secondary turns to the number of primary turns The turns ratio is the ratio of the secondary turns to the number of primary turns. The turns ratio determines the secondary voltage. More secondary turns result in an increase in voltage, and fewer secondary turns result in a decrease in voltage. The effect on amperage is reversed. More secondary turns result in a decrease in amperage, and fewer secondary turns result in an increase in amperage. For example, a transformer with a turns ratio of 101 will increase the voltage by a factor of 10, and decrease amperage by a factor of 10.

What type of grid error occurs when the x-ray beam is not aligned with the direction of the grid lines? Off-center Off-level Off-angulation Upside-down

Off-angulation Off-angulation grid errors occur when the x-ray beam is not aligned with the direction of the grid lines. Off-level grid errors are also known as "crooked grid" errors. Off-center grid errors occur when the central ray is not aligned to the middle of a focused grid. Upside-down grid errors occur only when a focus grid is not placed right side up.

What characteristic of off-focus radiation results in a loss of structural sharpness in a radiographic image? Off-focus radiation is lower energy than the primary beam Off-focus radiation is out of alignment with the primary beam Off-focus radiation is less penetrating than the primary beam Off-focus radiation is lower intensity than the primary beam

Off-focus radiation is out of alignment with the primary beam Misalignment with the primary beam is the characteristic that causes off-focus radiation to result in a loss of structural sharpness in the radiographic image. Structural sharpness refers to spatial resolution. Misaligned off-focus radiation creates a small amount of blur on the edges of objects. There are many other factors that can create blur and decrease spatial resolution. All the other options are true of off-focus radiation, but none of those characteristics are what affect the spatial resolution

Which type of grid error is also known as a "crooked grid"? Off-center Off-level Off-angulation Upside-down

Off-level Off-level grid errors are also known as "crooked grid" errors. Off-center grid errors occur when the central ray is not aligned to the middle of a focused grid. Off-angulation grid errors occur when the x-ray beam is not aligned with the direction of the grid lines. Upside-down grid errors occur only when a focus grid is not placed right side up.

Flat waveforms are used to ensure which of the following? Optimal occupational dose Optimal patient dose Correct patient positioning Correct histogram analysis

Optimal patient dose A flat waveform is important for ensuring optimal patient dose, not occupational dose. Waveforms are unable to ensure correct patient positioning nor that the histogram will be analyzed correctly.

Which of the following statements describes the relationship between milliamperage (mA and patient dose? Patient dose is directly proportional to the milliamperage (mA Patient dose is inversely proportional to the milliamperage (mA Patient dose is directly proportional to the square of the milliamperage (mA Patient dose is inversely proportional to the square of the milliamperage (mA

Patient dose is directly proportional to the milliamperage (mA Patient dose is directly proportional to the milliamperage (mA. The relationship is described as directly proportional because both variables change in the same direction and by the same factor. For example, if mA is increased by double, the patient dose will also increase by double.

The four patient factors related to spatial resolution are object-to-image distance OID, patient size, pathology, and which of the following? Kilovoltage peak (kVp) Milliampere-seconds (mAs) Patient movement Grid ratio

Patient movement There are four patient factors that influence spatial resolution. object-to-image distance (OID), patient size, pathology, and patient movement. Technical factors such as kilovoltage peak (kVp) and milliampere-seconds (mAs) do not influence the spatial resolution or sharpness of recorded detail in a radiographic image. Grid ratio will influence patient dose, receptor exposure, and contrast.

Which two of the following identifiers are required by law to be included on a radiographic image? Select two) Patient's name Patient's date of birth Patient's medical record number MRN Patent's social security number

Patient's name, Patient's date of birth A radiographic image must include the patient's name and date of birth, as well as the exam location, date performed, and a radiographic marker. The radiograph may also include the MRN, but this is not required by law.

An increase in tube potential would increase receptor exposure by increasing which two of the following? Select two) Focal spot size FSS Penetrating ability of the beam Attenuation of the beam Number of photons in the beam

Penetrating ability of the beam, Number of photons in the beam Tube potential is the same as kilovoltage peak (kVp). Increasing kVp does increase the number of photons in the beam (intensity) and the penetrating ability of the beam. This is because kVp increases the energy of photons in the beam. Increasing kVp actually decreases the attenuation of the beam because more photons will pass through the patient and strike the image receptor. Increasing tube potential will not have an effect on focal spot size.

During radiographic imaging of the chest, subject contrast is most likely to be increased with which of these pathological conditions? Aspiration of water Pleural effusion Cardiomegaly Pneumothorax

Pneumothorax Pneumothorax is likely to increase subject contrast. Pneumothorax refers to the accumulation of air in the pleural space, which commonly results in a collapsed lung. This excess air changes the attenuating properties of the chest such that there is an increase in the signal differences in the remnant being. The other answer options are not correct. Aspiration of water decreases subject contrast because the lungs will appear more similar to the surrounding soft tissues. Pleural effusion will decrease subject contrast due to the accumulation of fluid in the pleural space. Cardiomegaly refers to a pathologically enlarged heart, which is not expected to have an effect on subject contrast.

The appearance of off-focus radiation in the following image can be corrected by: Decreasing collimation Window leveling Post-processing shuttering Increasing kilovoltage peak (kVp)

Post-processing shuttering The appearance of off-focus radiation in this image can be corrected by post-processing shuttering. Shuttering is a post-processing technique used to crop out undesirable portions of the radiographic image. (increasing field size) would expose the patient to unnecessary radiation. Window leveling would affect the entire image, not just the area of off-focus radiation. Increasing kVp (with all other factors held constant) would overexpose the image

Which turn ratio is required for the autotransformer to step-up the incoming line voltage? Primary turns Np ) Secondary turns N s) Primary turns N p) Secondary turns N s ) Primary turns Np ) Secondary turns N s )

Primary turns N p) Secondary turns N s ) The autotransformer will step up (increase) the incoming line voltage when there are more secondary turns than primary turns. This means the turns ratio is greater than 1 and the autotransformer operates as a step-up transformer. The autotransformer will step down (decrease) the incoming line voltage when there are fewer secondary turns than primary turns. If the primary turns equal the secondary turns, there will be no change to the voltage.

Which turn ratio is required for the autotransformer to step-down the incoming line voltage? Primary turns Np ) Secondary turns Ns ) Primary turns Np ) Secondary turns Ns ) Primary turns Np ) Secondary turns Ns )

Primary turns Np ) Secondary turns Ns ) The autotransformer will step-down (or decrease) the incoming line voltage when there are FEWER secondary turns than primary turns. This means the turns ratio is less than 1 and the autotransformer operates as a step-down transformer. The autotransformer will step up (increase) the incoming line voltage when there are more secondary turns than primary turns. If the primary turns equal the secondary turns, there will be no change to the voltage.

Which of the following describes the x-ray tube current? Duration of electron flow Direction of electron flow Energy of electron flow Quantity of electron flow

Quantity of electron flow Tube current describes the quantity, or number, of electrons flowing through the x-ray tube. Tube current is measured in units of milliamperage (mA. Duration of the electron flow is the exposure time. The direction of the flow is from cathode to anode. Energy of the flow is determined by the kVp

The highest exposure readings on a radiographic histogram usually represent areas of: Soft tissue Calcification Raw exposure outside of the body part Collimation

Raw exposure outside of the body part The highest exposure readings on a radiographic histogram usually represent areas of raw exposure outside the body part, such as the air above the shoulder on a chest radiograph. The detector is exposed to the full intensity of the xray beam, so the exposure reading is very high. These high exposure readings are excluded from the values of interest during histogram analysis.

Which statement describes the relationship between source-to-image distance SID and receptor exposure? Receptor exposure is inversely proportional to the square of the SID Receptor exposure is directly proportional to the square of the SID Receptor exposure is inversely proportional to the SID Receptor exposure is directly proportional to the SID

Receptor exposure is inversely proportional to the square of the SID Receptor exposure is inversely proportional to the square of the source-to-image distance SID. This relationship is mathematically defined by the inverse square law. For example, if the SID is increased by a factor of 2, the receptor exposure decreases by a factor of 2 squared 4.

While servicing a malfunctioning x-ray tube, the engineer observes that the x-ray tube is receiving alternating current AC. What device within the x-ray circuit is likely responsible for this malfunction? Rectifier Step-up transformer Step-down transformer Exposure timer

Rectifier This malfunction is likely caused by the failure of a rectifier. The x-ray tube must receive direct current DC, not alternating current AC, in order to ensure electrons only flow from the cathode filament to the anode. Rectifiers receive AC from the step-up transformer and convert AC into DC which is then supplied to the x-ray tube. If the x-ray tube is receiving AC a rectifier has failed.

To reduce the patient dose by ½, what must be done to the milliamperage (mA if all other factors are held constant? Reduce mA by ¼ Reduce mA by ½ Increase mA by ¼ Increase mA by ½

Reduce mA by ½ Milliamperage (mA is directly proportional to patient dose. If the mA is reduced by ½, then the patient dose also needs to be reduced by ½.

Which part of the x-ray beam has different signal intensities that correspond to the anatomy represented on the image receptor IR? Primary beam Remnant beam Corresponding beam Receptor beam

Remnant beam The remnant beam has different signal intensities that correspond to the anatomy represented by that part of the beam on the image receptor IR. The remnant, or exit, beam is the portion of the x-ray beam that exits out of the patient and reaches the IR. The primary beam consists of the x-ray beam that interacts with the patient. Corresponding beam and receptor beam are not real terms.

A technologist received a requisition for a two-view knee radiograph, but the technologist performed a two-view tibia-fibula series. How should this error be corrected? Request a new order to include the examination performed Adjust the order to match the examination performed Repeat the examination on the correct body part No action is needed

Repeat the examination on the correct body part The technologist must repeat the examination on the correct body part. The order and the request were not incorrect, so it does not need to be reordered/requested. Action is needed.

A dead detector element DEL is visible within a radiograph of the orbits performed for magnetic resonance imaging MRI screening. How can the technologist correct this error? Repeat the exposure with a different image receptor IR= Repeat the exposure with a different x-ray tube Reprocess the raw data with a different histogram protocol Repeat the exposure after cleaning both the x-ray tube housing and the image receptor IR

Repeat the exposure with a different image receptor IR= This exposure must be repeated using a different image receptor IR. There is no way to retrieve the missing information from the dead detector element.

A technologist accidentally processes a chest radiograph under the abdomen histogram protocol. How should this mistake be corrected? Adjust the brightness and contrast in Medical Image Management and Processing System MIMPS Repeat the exposure using the correct histogram protocol Reprocess the raw data using the correct histogram protocol No action is necessary

Reprocess the raw data using the correct histogram protocol If the technologist processes an image using the wrong histogram protocol, the technologist should reprocess the raw data using the correct histogram protocol. This is performed on the x-ray computer system. Action is necessary, but there is no need to repeat the exposure. Also, adjustments should be made prior to sending the images to Medical Image Management and Processing System MIMPS.

What is the process called that converts the original radiographic histogram to the expected histogram? Histogram analysis Rescaling Lookup table LUT conversion Post-processing

Rescaling Rescaling is the process through which the original histogram is converted to the expected histogram. Histogram analysis is the process through which the values of interest are identified. The Lookup Table is used to adjust pixel values to the proper contrast and brightness. Post-processing is changes made to the image after the computer has processed it (such as window leveling, annotation, etc.).

What is used to test a monitor's spatial resolution? SMPTE test pattern Moire pattern Spinning top test Star patter-type resolution test

SMPTE test pattern A SMPTE pattern is used to evaluate a monitor's spatial resolution. The moire pattern is an artifact seen in images. The spinning top test is used to evaluate timer accuracy. Star pattern-type resolution test is used to evaluate the focal spot size.

Which of the following might be an adverse effect of an incorrect kilovolt (kV waveform? Moire pattern, mottle, and excessive dose Saturation, moire pattern, and excessive dose Saturation, mottle, and excessive dose Saturation, mottle, and moire pattern

Saturation, mottle, and excessive dose Adverse effects of an incorrect waveform include saturation, mottle, and excessive dose. Moire patterns are wavy lines across the image caused by grid lines being parallel with the computed radiography CR plate reader's scanning direction

What is the unit of measure for exposure time? Milliamperage (mA) Kilovoltage peak (kVp) Seconds (s) Milligray Per second (mGy/s)

Seconds (s) The unit of measure for exposure time is seconds (s). Milliamperage (mA) is the unit of measure for tube current, kilovoltage peak (kVp) is the unit of measure for tube potential, and milligray per second (mGy/s) is a common unit of measure for dose rate

Large visible differences in brightness are defined as: Long gray-scale, high contrast, and many shades of gray Short gray-scale, high contrast, and many shades of gray Long gray-scale, low contrast, and few shades of gray Short gray-scale, high contrast, and few shades of gray

Short gray-scale, high contrast, and few shades of gray Remember, image contrast is defined as the visible differences in brightness on a radiographic image. Large visible differences would indicate the presence of only a few shades of gray and more black and white. Another way to describe this type of radiograph would be as having a short gray-scale and high contrast.

What waveform is represented in the following image? Single-phase unrectified Single-phase half-wave rectified Single-phase full-wave rectified Three-phase unrectified Three-phase six-pulse High-frequency

Single-phase full-wave rectified This illustration represents a single-phase full-wave rectified waveform. There is just one distinct waveform, the single-phase, and the negative voltage pulses that have inverted to the positive voltage. This is named "full-wave rectified" because the entire wave is now converted to a pulsating direct current. Single-phase unrectified would show a single waveform with both positive and negative voltage pulses. Single-phase half-wave rectified would show a single waveform, but with positive pulses only and gaps where the negative pulses used to be. Three-phase unrectified are three distinct waveforms that reverse back and forth between positive and negative voltage. Threephase six-pulse are three distinct waveforms where the negative portion of each wave has been rectified, creating six total voltage pulses per wave cycle. High-frequency has numerous voltage pulses with very little loss of voltage between pulses.

Which of the following situations regarding source-to-image distance SID is correct as it relates to size distortion? Size distortion increases with a longer SID Size distortion decreases with a longer SID Size distortion is independent of SID

Size distortion decreases with a longer SID Source-to-image distance SID is one of the factors that controls the amount of magnification present in an image, and the relationship is inverse. As SID increases, size distortion decreases, meaning that less magnification will be present with a longer SID.

What aspects of the image receptor IR influence spatial resolution? Size, pitch, & number of detector elements (dexels) Size, pitch, & number of picture elements (pixels) Shape, pitch, & number of picture elements (pixels) Shape, pitch, & number of detector elements (dexels)

Size, pitch, & number of detector elements (dexels) Spatial resolution is influenced by the receptor itself— specifically, the size, pitch, and number of detector elements. Pixels are located in the monitor, not the detector. Dexel shape is not a factor influencing spatial resolution.

Which of the following combinations would produce an image with the highest spatial resolution? Small DEL size, small DEL pitch, high fill factor Small DEL size, small DEL pitch, small fill factor Small DEL size, large DEL pitch, small fill factor Large DEL size, large DEL pitch, high fill factor

Small DEL size, small DEL pitch, high fill factor A small detector element DEL size increases spatial resolution. DEL pitch is the measurement between the DELs. Smaller DEL pitch results in less distance between the pixels and a reduction in the information gap. A higher fill factor reduces gaps in information and increases spatial resolution.

How is source-to-object distance SOD calculated? Source-to-image distance SID - object-to-image distance OID Source-to-image distance SID object-to-image distance OID Source-to-image distance SID X object-to-image distance OID Source-to-image distance SID object-to-image distance OID

Source-to-image distance SID - object-to-image distance OID Source-to-image distance SID - object-to-image distance OID source-to-object distance SOD. This will be needed to calculate the focal spot blur.

The distance between the anatomy being imaged and the focal spot within the x-ray tube is called: Source-to-image distance SID Object-to-image distance OID Source-to-object distance SOD Focal spot size FSS

Source-to-object distance SOD Source-to-object distance (SOD) stands for source-to-object distance. The source refers to the source of x-ray production, the focal spot on the anode, and the object refers to the anatomy being imaged. If the x-ray tube is moved further from the patient due to an increase in source-to-image distance (SID), SOD will also increase. SID is the distance between the source and the image receptor. OID is the distance between the object (anatomy) and the image receptor. FSS is simply the size of the focal spot and is not a distance.

What type of transformer is required to increase amperage so that it will sufficiently heat the filament for thermionic emission in the x-ray tube circuit? Step-up transformer Step-down transformer Autotransformer

Step-down transformer In order to sufficiently heat the filament, a step-down transformer is needed to increase amperage for thermionic emission in the x-ray tube circuit. A step-down transformer will decrease voltage V, but increase amperage. Transformers are named according to how they change the voltage, and amperage is always changed in the opposite direction. Therefore, a step-down transformer would be required to increase amperage

A transformer with a turns ratio greater than one is described as which of the following? Step-up transformer Step-down transformer Autotransformer

Step-up transformer A transformer with a turns ratio greater than one is a step-up transformer. The turns ratio can be represented as a fraction with the number of secondary turns as the numerator and the number of primary turns as the denominator. If a fraction is greater than one, then the top number is greater than the bottom, meaning the number of secondary turns would be greater than the number of primary turns. This situation describes a step-up transformer. Any transformer with a turns ratio greater than 1 is a step-up transformer.

In order to ensure optimal receptor exposure, the portion of the patient's anatomy that should be positioned over the active automatic exposure control AEC chamber is the: Structure of primary concern Structure of least concern Highest density structure Lowest density structure

Structure of primary concern The structure of primary concern should always be placed over the active automatic exposure control (AEC) cell(s). AEC systems are designed to maintain optimal receptor exposure for the structures over the active AEC cells. When imaging the chest, the lungs should be positioned over the active outer cells and the center (under the spine) should be deactivated. A chest x-ray requires optimal exposure through the lung fields, not the thoracic spine.

If a radiograph demonstrates an "S" (sensitivity) number of 80 with no visible exposure errors, the technologist should consider which of the following actions? Repeat the radiograph using a larger grid ratio Submit the radiograph as-is without repeating the exposure Repeat the radiograph using a smaller exposure technique Repeat the radiograph using a larger exposure technique

Submit the radiograph as-is without repeating the exposure The radiograph should be submitted for interpretation. No repeat is necessary. Although the "S" or sensitivity number of 80 indicates the receptor was over-exposed, a repeat radiograph is only necessary when the image is visibly degraded by exposure artifacts such as saturation or mottle. If a repeat was requested the technologist would want to decrease the technical values since the S number of 80 indicates that the exposure was higher than necessary. A larger grid ratio is not recommended since it would require an increase in mAs which would cause more of an over exposure.

A perfect kilovolt (kV waveform should generate the selected kV from: The beginning, overshoot in the middle, and undershoot at the end The beginning to the end of the exposure The beginning, undershoot in the middle, and overshoot at the end Overshoot at the beginning and undershoot at the end

The beginning to the end of the exposure The perfect kilovolt (kV waveform should generate the selected kV from the beginning to the end of the exposure. The waveform should not overshoot or undershoot at any point.

The milliampere (mA waveform must be regularly updated as the tube ages because: New technologists may use the machine Different procedures require different waveforms The x-ray tube properties can change over time Different patients require different waveforms

The x-ray tube properties can change over time The milliampere (mA waveform must be regularly updated as the tube ages because the x-ray tube properties can change over time. Waveforms should remain the same regardless of the healthcare workers, procedures, or patients.

What is the relationship between milliamperage (mA and photon quality? Directly proportional Inversely proportional Inversely proportional to the square There is no relationship

There is no relationship There is no relationship between milliamperage (mA and photon quality.

Which component of the x-ray circuit must be powered by alternating current AC in order to function correctly? Rectifiers Milliamperage (mA selector Transformers Exposure timer

Transdormers All transformers within the x-ray circuit must be powered by alternating current (AC to function correctly. Alternating current (AC creates a fluctuating magnetic field, which in turn causes electromagnetic induction within the transformers. Direct current (DC does not cause electromagnetic induction. Rectifiers are used to convert AC to DC. The milliamperage (mA selector has resistors to vary the flow rate of electricity that is delivered to the filament transformer. The exposure timer is used to make and break the high voltage across the x-ray tube.

Kilovoltage peak (kVp) in the x-ray tube is the unit of measurement describing: Heat accumulation Electrical waveform Tube potential Tube current

Tube potential Kilovoltage peak (kVp) is the unit of measure describing tube potential or tube voltage.

What is the main effect of grid cut-off? Overexposure of the image receptor Decreased image contrast Underexposure of the image receptor Reduced image spatial resolution

Underexposure of the image receptor Grid cut-off results in underexposure of the image receptor. Grid cut-off is the absorption of some of the useful x-ray beams, meaning that less radiation will reach the image receptor.

What effect does receptor exposure have on image quality? Proper exposure results in saturation Underexposure results in quantum mottle Proper exposure results in quantum mottle Overexposure results in quantum mottle

Underexposure results in quantum mottle Underexposure results in quantum mottle. Overexposure results in saturation. Proper exposure should not result in either saturation or quantum mottle

What type of grid error occurs only when a focus grid is not placed right side up? Off-center Off-level Off-angulation Upside-down

Upside-down Upside-down grid errors occur only when a focus grid is not placed right side up. Off-level grid errors are also known as "crooked grid" errors. Off-center grid errors occur when the central ray is not aligned to the middle of a focused grid. Off-angulation grid errors occur when the x-ray beam is not aligned with the direction of the grid lines.

The step-up transformer in the x-ray circuit serves to modify the current within the x-ray system by converting which of the following? Amps to kilo-amps Low-frequency to high-frequency Volts (V to kilovolts (kV Single-phase to three-phase

Volts (V to kilovolts (kV The step-up transformer converts volts (V into kilovolts (kV. This device is important because the incoming line voltage is only 220 V, but the power arriving at the x-ray tube must be nearly 1,000 times higher in the kilovoltage range. Without increasing the voltage to kilovoltage, electrons within the x-ray tube would not have enough energy to create x-rays.

What is the anode heel effect caused by? Excessive filament temperature Inadequate anode rotation speed Excessive heat production within the anode X-ray absorption within the anode

X-ray absorption within the anode The anode heel effect is caused by x-ray absorption within the anode. Fewer photons are escaping the heel of the anode, so the anode side of the beam is less intense and the cathode side is more intense. The filament temperature affects how many electrons are boiled off. A slower rotation speed would cause the anode to heat up faster. The anode heel effect does not cause excessive heat production

A lateral radiograph of the knee demonstrates the superimposition of a femoral condyle over the joint space. This error can be corrected by adjusting the: Lateral rotation of the knee Flexion of the knee Receptor position X-ray tube angulation

X-ray tube angulation The appearance of a femoral condyle over the femoral tibial-joint space should be corrected by adjusting the x-ray tube angulation. The direction of angulation depends on which femoral condyle is superimposing the joint space. The other answer options are not correct. Lateral rotation of the knee, flexion of the knee, and receptor position have no effect on the superimposition of the condyles within the joint space.

Shape distortion is related to a misalignment of, or angle present, on which three of the following? Select three) Source-to-image distance SID X-ray tube Focused grid Anatomy being imaged Image receptor IR

X-ray tube, Anatomy being imaged image receptor IR Shape distortion is created when any of these three components of the exposure, x-ray tube, anatomy of interest, or image receptor IR, is situated at an angle related to the others. An angle on the tube, anatomy positioned at an angle, or an angled image receptor will all result in some form of shape distortion. Focused grids filter out some of the photons in the beam, but won't distort the image. Source-to-image distance SID controls size distortion which includes magnification of the part. Increasing object-to-image distance OID will magnify the object causing size distortion. SID will decrease magnification reducing size distortion.

What component of the x-ray tube is the source of x-rays? Tube housing Glass envelope Anode Cathode

anode The anode is the source of x-rays within the x-ray tube. When high-energy electrons from the cathode collide with tungsten atoms within the anode, these interactions create x-ray photons and heat. The specific interactions that create x-ray photons are called Bremsstrahlung radiation and characteristic radiation. The cathode is the source of free electrons, not x-rays. The tube housing protects the x-ray tube and the glass envelope maintains the necessary vacuum.

Off-focus radiation is the product of electron interactions occurring within which three components of the x-ray tube? Select three) Cathode assembly Anode target Vacuum envelope Anode disk

cathode assembly, vacuum envelope, anode disk Off-focus radiation is created when electrons interact within any component of the x-ray tube away from the actual focal spot. This can include the cathode assembly, vacuum envelope, and anode disk. The anode target does not have off-focus radiation, as it is the focal area for x-ray production.

The loss of visually distinct brightness levels from off-focus radiation within the primary beam is described as decreased: Receptor exposure Contrast Bit depth Spatial resolution

contrast The loss of visually distinct brightness levels from off-focus radiation within the primary beam is described as decreased contrast. Contrast refers to the visible difference in brightness levels. Off-focus radiation is similar to scatter radiation in that it creates meaningless noise on the radiograph. This noise makes the brightness levels less distinct and therefore decreases image contrast. Off-focus radiation adds to the receptor exposure and has no effect on bit depth. Off-focus radiation does decrease spatial resolution, but spatial resolution is not defined as the loss of visually distinct brightness levels.

Which of the following grid types can't be used when tube angulation is required? Focused Grid Crossed Grid Linear Grid Parallel Grid

crossed grid Crossed grids must be perfectly positioned within the x-ray field. They can't be used if the x-ray beam requires any angulation. For this reason, crossed grids are not often used in a diagnostic x-ray. Tube angulation can be used for linear, parallel, and focused grids

Technologists can reduce the chance of excessive heat production and x-ray tube damage by modifying the: Filament size Anode angle Anode rotation speed Anode size

filament size Technologists can reduce the chance of excessive heat production and x-ray tube damage by modifying the filament size. Technologists may select a large or small focal spot at the control panel to determine which filament will be used for the exposure. The large filament will result in an electron beam that strikes a larger surface area at the focal spot, which will decrease the concentration of heat produced. The other choices provided are not variables that the technologist can adjust.

Electron interactions within the x-ray tube anode primarily create: Ultraviolet rays Heat X-rays Visible light

heat Approximately 99% of electron energy within the x-ray tube is converted to heat within the anode. The remaining 1% is converted to x-rays. For this reason, x-ray production is considered a very inefficient process.

Which of the following is a potentially negative consequence of an increased anode angle? Decreased effective focal spot Decreased anode heel effect Increased effective focal spot Increased anode heel effect

increased effective focal spot As anode angle increases there is a decrease in the anode heel effect and an increase in the effective focal spot size. A decrease in the heel effect is a positive outcome, while the increased effective focal spot size would lead to decreased spatial resolution, a potentially negative outcome.

What technical change is required to increase receptor exposure when using automatic exposure control AEC? Increased milliamperage (mA) Increasing the density setting Decreased kilovoltage (kVp) Decreased back-up timer

increasing the density setting increasing the density setting is the primary way to increase receptor exposure when using automatic exposure control (AEC). The AEC system is designed to maintain the appropriate receptor exposure, even when variables such as the patient size, milliamperage (mA), and kilovoltage peak (kVp) are changed. Increasing the density setting increases the exposure level at which the system terminates the exposure. Increasing the mA increases the exposure RATE and decreases the exposure TIME, but does not change the total receptor exposure

What type of transformer must be used in the filament circuit in order for thermionic emission to be possible? Step-up transformer step-down transformer Autotransformer

step-down transformer A step-down transformer is required in the filament circuit to increase amperage to the level needed for thermionic emission. A step-down transformer works to decrease voltage and increase amperage. The other answer options are not correct. A step-up transformer decreases the amperage, and an autotransformer only makes very small changes to the amperage. Neither of these devices create the high amperage necessary for thermionic emission within the filament circuit.