Ch. 1 image analysis Ch. 1 image analysis | Exams Radiography

Ch. 1 image analysis

Three images were obtained on the same structure with a computed radiography system. Image 1 was

obtained using a 48- inch source-image receptor distance (SID) and a 5-inch object- image receptor

distance (OID); image 2 was obtained using a 48-inch SID and a 3-inch OID; and image 3 was

obtained with a 48-inch SID, a 3-inch OID, and a larger IR. Which image will demonstrate the sharpest

recorded detail? -

Image 2

A rotating collimator head 1. can be rotated without rotating the entire tube column on DR systems. 2.

does not affect the alignment of the beam with the grid. 3. allows the technologist to increase

collimation on projections when the longitudinal axis of the anatomical structure is not aligned with the

longitudinal or transverse axis of the IR. 4. should be avoided when using computed radiography

because it may affect the exposure field recognition process. -

1, 2, 3, and 4

The most common shape distortion is a.magnification. -

elongation

The greatest detail sharpness is obtained by using 1. a small focal spot. 2. the longest SID. 3. the

smallest OID. 4. longer exposure times. -

1, 2, and 3 only

What is the marker placement for the projection of PA cranium? -

Laterally on the side being identified

To correctly mark a cross-table lateral hip projection, 1. place the marker anteriorly to prevent it from

obscuring posterior structures. 2. place the marker to indicate the side closest to the IR. 3. place the

marker toward the edge of the IR outside the exposure field. 4. include an arrow to indicate the side

positioned away from the table or cart. -

1 and 2 only

To properly display extremity projections, display 1. finger, wrist, and forearm projections as if the

patient were hanging from the fingertips. 2. elbow and humeral projections as if they were hanging

from the patient's shoulder. 3. toe and AP and PA oblique foot projections as if the patient were hanging

from the toes. 4. lateral foot, ankle, lower leg, knee, and femur projections as if they were hanging from

the patient's hip. -

1, 2, and 4 only

Minimizing size distortion is accomplished by which of the following? 1. Using the longest feasible

SID 2. Using the shortest possible OID 3. Decreasing the angle of the CR 4. Placing the part as close to

the IR as possible -

1, 2, and 4 only

Two structures are 4.5 inches apart and out of superimposition 2.25 inches. To bring them into

superimposition, the CR should be angled ______degrees. -

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Ch. 1 image analysis

Three images were obtained on the same structure with a computed radiography system. Image 1 was obtained using a 48- inch source-image receptor distance (SID) and a 5-inch object- image receptor distance (OID); image 2 was obtained using a 48-inch SID and a 3-inch OID; and image 3 was obtained with a 48-inch SID, a 3-inch OID, and a larger IR. Which image will demonstrate the sharpest recorded detail? - Image 2 A rotating collimator head 1. can be rotated without rotating the entire tube column on DR systems. 2. does not affect the alignment of the beam with the grid. 3. allows the technologist to increase collimation on projections when the longitudinal axis of the anatomical structure is not aligned with the longitudinal or transverse axis of the IR. 4. should be avoided when using computed radiography because it may affect the exposure field recognition process. - 1, 2, 3, and 4 The most common shape distortion is a.magnification. - elongation The greatest detail sharpness is obtained by using 1. a small focal spot. 2. the longest SID. 3. the smallest OID. 4. longer exposure times. - 1, 2, and 3 only What is the marker placement for the projection of PA cranium? - Laterally on the side being identified To correctly mark a cross-table lateral hip projection, 1. place the marker anteriorly to prevent it from obscuring posterior structures. 2. place the marker to indicate the side closest to the IR. 3. place the marker toward the edge of the IR outside the exposure field. 4. include an arrow to indicate the side positioned away from the table or cart. - 1 and 2 only To properly display extremity projections, display 1. finger, wrist, and forearm projections as if the patient were hanging from the fingertips. 2. elbow and humeral projections as if they were hanging from the patient's shoulder. 3. toe and AP and PA oblique foot projections as if the patient were hanging from the toes. 4. lateral foot, ankle, lower leg, knee, and femur projections as if they were hanging from the patient's hip. - 1, 2, and 4 only Minimizing size distortion is accomplished by which of the following? 1. Using the longest feasible SID 2. Using the shortest possible OID 3. Decreasing the angle of the CR 4. Placing the part as close to the IR as possible - 1, 2, and 4 only Two structures are 4.5 inches apart and out of superimposition 2.25 inches. To bring them into superimposition, the CR should be angled ______degrees. -

The quality of spatial resolution of a digital imaging system is mainly defined by 1. the size of the matrix. 2. the size of the pixel within the matrix. 3. the spatial frequency. 4. line pairs per millimeter (Ip/mm). - 1 and 2 only Anatomical relationships are affected by 1. varying degrees of patient obliquity and flexion. 2. off centering. 3. geometrical factors of magnification, elongation, and foreshortening. 4. similar structures of shape and size. - None of the above What is the marker placement for the projection of PA oblique vertebrae? - Laterally, identifying the side situated closer to the IR The off-centered diverged beams of a perpendicular CR will affect structures in the same manner as an angled CR. Which of the following statements best describes this relationship? 1. At a 40-inch SID, the divergence of x-rays is 1 degree for every inch off-centered in any direction from the CR. 2. At a 48- inch SID, beam divergence is off-centered about 2 degrees for every inch in any direction from the CR.

At a 40-inch SID, the divergence of x-rays is 2 degrees for every inch off-centered in any direction from the CR. 4. At a 72-inch SID, beam divergence is off-centered about 1 degree for every inch. - 3 and 4 only Effective radiation protection practices include all of the following except 1. effective communication and immobilization devices. 2. maintaining minimum source to skin distances (SSD). 3. oscillating grids and contact shields. 4. collimation and minimizing technical factors. - 3 only For an open joint space to be obtained, the central ray must be aligned______to the joint. - parallel All of the following statements about display stations are true except 1. if the digital system matrix size is smaller than the display station's matrix size, the values of surrounding pixels will be averaged to display the whole image. 2. to display images at full resolution, the display monitor must be able to display the same number of pixels as those at which the digital system acquired the image. 3. display station resolution refers to the maximum number of pixels that the screen can demonstrate. 4. the technologist's workstation display monitors typically demonstrate resolution as high as that of the radiologist's display monitor. - 4 only? A postprocessing manipulation that can be added to digital projections as a means of helping the viewer to better evaluate contrast resolution in the selected area is a - contrast mask Diagnostic imaging professionals have a responsibility to adhere to effective radiation protection practices for which of the following reasons? 1. The risk of cancer from radiologic examinations accumulates over a lifetime. 2. To limit the risk of stochastic effects to a reasonable level compared with nonradiation risks and in relation to society's needs, benefits gained, and economic factors. 3. Good patient care standards dictate the use of effective radiation protection practices. 4. Continually

the system algorithm does not recognize a diagonal exposure field. 4. Align the long bone parallel to the IR to prevent a histogram analysis error. - 1, 2, 3, and 4 The patient demographic requirements for radiographic images include all of the following except - technologist's identification. A small focal spot should be used for each of the following situations except when - the milliamperage setting is above 300. Placing a marker directly on the tabletop 1. avoids marker distortion and magnification. 2. prevents scatter radiation from undercutting the marker. 3. ensures the marker will not be projected off the IR. 4. attenuates most but not all of the incident x-rays. - 1, 2, and 3 only Collimation guidelines include all of the following except for 1. chest and abdomen projections, collimate to within 1 inch (2.5 cm) of patient's skin line. 2. extremity projections, collimate to within 0.5 inch (1.25 cm) of the skin line of the thickest VOI. 3. chest and abdomen projections, collimate to within 0.50 inch (1.25 cm) of the IR edge. 4. collimating structures within the torso, bring the collimated borders to within 1 inch (2.5 cm) of the VOI. - 1 and 3 Two structures are 2.5 inches apart and out of superimposition 1.5 inches. To bring them into superimposition, the CR should be angled_______degrees. - 15 Good collimation practices result in which of the following? 1. Reduces histogram analysis errors 2. Clearly delineates the VOI 3. Improves the visibility of recorded details by reducing the amount of scatter radiation that reaches the IR 4. Decreases the radiation dosage by limiting the amount of scatter from the patient - 1, 2, and 3 only When the central ray is angled, the structure situated____ is projected the most. - farther away from the IR Which of the following is true about image markers? 1. They are radiopaque. 2. They should be reversed before being placed on the IR. 3. They should be positioned as close to the median plane as possible. 4. They will be magnified if positioned on the imaging table or patient. - 1 and 4 only To shield the female gonads properly, 1. use a flat contact shield made from at least 0.5 mm of lead. 2. use a flat contact shield cut to the shape of the inlet pelvis. 3. the dimensions of the shield used are determined by the OlID and SID and by the size of the patient's pelvis. 4. the entire inlet pelvis should be shielded. - 2, 3, and 4 only Good collimation practices will do all of the following except - reduce the visibility of recorded details.

What is the marker placement of the projection of lateral hand. - Anywhere within the exposure field Gonadal shielding is recommended in which of the following situations? - 1,2 and 3 only

Ch. 1 image analysis Ch. 1 image analysis, Exams of Radiography

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Ch. 1 image analysis