Positioning Lab Possible Final Positions Flashcards
AP Lordotic CXR
Also called the Lindblom method
- image receptor size: 14 x 17
- SID 72 inches to decrease magnification
- Patient in upright position, facing the x-ray tube and standing 1 foot in front of the vertical grid device
- adjust height of the IR so that the upper margin is about 3 inches above the upper border of the shoulders when the patient is adjusted in the lordotic position
- adjust patient for the AP axial projection with the coronal plane of the thorax 15-20 degrees from the vertical and midsagittal plane centered to the midline of the grid
- CR 3-4 inches below jugular notch, at the level of T7
- if patient is unable to lean back the CR can be angled 15-20 degrees cephalad
- apices can be displayed also by shooting a PA axial with 15 degrees on CR through T3 to center of 10 x 12 IR and patient is standing erect.
Evaluation criteria
• evidence of proper collimation
• entire apices and appropriate portion of lungs
• clavicles located superior to apices
• sternal ends of the clavicles equidistant from the vertebral column
• clavicles lying horizontally with their sternal ends overlapping only the first or second ribs
• ribs distorted with with their anterior and posterior portions superimposedx
Lateral decubitus chest
- 14 x 17 IR
- patient laying affected side if fluid, this is so the mediastinal shadows and fluid do not overlap.
- patient laying on unaffected side if free air
- have patient in position for 5 minutes and secure to ensure they do not fall.
- if patient is laying on affected side to demonstrate pleural effusion, elevate body 2-3 inches
- extend arms well above head, and adjust the thorax in true lateral position
- place the anterior or posterior surface of the chest against a vertical grid device
- adjust IR so that it extends approximately 1.5-2 inches beyond the shoulders
- shield gonads
CR
• horizontal and perpendicular to the center of the IR at a level 3 inches below the jugular notch for AP and T7 for PA
Structures shown
• AP or PA projection obtained using the lateral decubitus position shows the change in fluid position and reveals any previously obscured pulmonary areas or in the case of suspected pneumothorax, the presence of any free air.
Evaluation criteria
• proper collimation
• affected side in its entirety, from apex to costophrenic angle
• no rotation from frontal as demonstrated by the sternal ends of the clavicles equidistant from the spine
• patients arms not visible in field of interest
• proper identification visible to indicate that the decubitus position was performed
Upright Abdomen
Know reasonable technique for lab partner as well
Average technique for upright abdomen:
85kVp 25mAs
- 14 x 17 IR lengthwise
- patient in upright position
position of part
• center the midsagittal plane of the body to the midline of grid device
• distribute the weight of the body equally on the feet
• place patients arms out of image and not casting shadow
• center the IR/CR 2 inches above the level of the iliac crests or high enough to include the diaphragm
• if the bladder is going to be included on upright image, center IR/ CR at the level of iliac crests
• shield gonads
• suspend after expiration so abdominal organs are not compressed
central ray
• horizontal and 2 inches above the level of the iliac crests to include the diaphragm for upright
Structures shown
• AP projection of the abdomen shows the size and shape of the liver, spleen, and kidneys and intra-abdominal calcifications or evidence of tumor masses
Evaluation criteria
• proper collimation
• area from the pubic symphysis to the upper abdomen( two images if patient is tall or wide)
• proper patient alignment, as ensured by; centered vertebral column; ribs, pelvis, and hips equidistant to the edge of the image
• no rotation of the patient as demonstrated by; spinous processes in the center of lumbar vertebrae. Ischial spines of the pelvis symmetric, if visible. Alae or wings of the ilia symmetric
• soft tissue brightness and contrast showing the following; lateral abdominal wall and properitoneal fat layer(flankstripe). Psoas muscles, lower border of the liver, and kidneys. Inferior ribs. Transverse processes of the lumbar spine
• right or left marker visible but not superimposed in abdominal contents
• diaphragm without motion on upright abdominal examinations
Left lateral decubitus abdomen
Reasonable technique for lab partner.
Base technique
85kVp 28mAs
• 14 x 17 IR
Position of patient
• lay patient in lateral recumbent position on radiolucent pad
• have patient on side for 5 minutes before exam if possible
• arms above level of diaphragm
• flex patients knees for stabilization
Position of part
• adjust the height of the vertical grid device so that the long axis of IR is centered to midsagittal plane
• position the patient so that the level of the iliac crests is centered to the IR. A slightly higher centering point, 2 inches, may be necessary to ensure that the diaphragms are included in the image
• adjust the patient to ensure that a true lateral is attained
• shield
Suspend respiration at end of expiration
Central Ray
• directed horizontal and perpendicular to the midpoint of the IR
Structures shown
• in addition to showing the size and shape of the liver, spleen, and kidneys, the AP abdomen with the patient in the left decubitus position is most valuable for showing free air and fluid levels when an upright cannot be obtained
Evaluation criteria
• proper collimation
• diaphragm without motion
• both sides of abdomen
• abdominal wall, flank structures, and diaphragm
• no rotation; spinous processes in the center of the lumbar vertebrae, ischial spines of the pelvis symmetric, alae or wings of the ilia symmetric
• brightness and contrast to demonstrate abdominal contents
• markers
PA hand
- 8 x 10 IR
- adjust patient height so that the forearm is resting on the table
Position of part
• hand with palmar surface down on IR
• center the IR to the MCP joints, and adjust the long axis of the IR parallel with the long axis of the hand and forearm
• spread fingers slightly
• ask patient to relax hand to avoid motion
• shield
Central ray
• perpendicular to the third MCP joint
Collimation
• 1 inch on all sides of the hand, including 1 inch proximal to the ulnar styloid
Structures shown
• PA projections of the carpals, metacarpals, phalanges, interarticulations of the hand, and distal radius and ulna are shown
Evaluation criteria
• proper collimation
• anatomy from fingertips to distal radius and ulna
• slightly separate digits with no soft tissue overlap
• no rotation; equal concavity of the metacarpal and phalanges bodies on both sides: equal amount of soft tissue on both sides of the phalanges: fingernails, if visualized, in the center of each distal phalanx: equal distance between, the metacarpal heads
• open MCP and IP joints, indicating that the hand is placed flat on the IR
• SOFT TISSUE AND BONY TRABECULAR DETAIL
PA OBLIQUE HAND
• 8 x 10 IR
Patient position
• seated at end of table
• adjust patients height to rest the forearm on the table
Part position
• rest forearm on the table with the hand probated and palm resting on IR
• adjust the obliquity of the hand so that the MCP joints form an angle of approximately 45 degrees with the IR plane. Use wedge if available
Central ray
• perpendicular to the third MCP joint
Collimation
• 1 inch on all sides including 1 inch proximal to the ulnar styloid
Structures shown
• the resulting image shows a PA oblique projection of the bones and soft tissues of the hand. Used for investigating fractures and pathological conditions
Evaluation criteria
• proper collimation
• anatomy from fingertips to distal radius and ulna
• digits separated slightly with no overlap of their soft tissues
• 45 degrees of rotation of anatomy; minimal overlap of the third, fourth, and fifth metacarpal bodies; slight overlap of the metacarpal bases and heads’ separation of the second and third metacarpals
• open IP and MCP joints
• soft tissue and bony trabecular detail
AP elbow
- 8 x 10 IR
- patient seated near the radiographic table and low enough to place the shoulder joint, hummerus, and elbow joint in same plane
Position of part
• extend elbow, supinate the hand, and center the IR to the elbow joint
• adjust the IR to make it parallel with the long axis of the part
• have the patient lean laterally until the humeral epicondyles and anterior surface of the elbow are parallel with the plane of the IR
• supinate the hand to prevent rotation of the bones of the forearm
• shield
Central ray
• perpendicular to the elbow joint
Collimation
• 3 inches proximal and distal to the elbow joint and 1 inch on the sides
Structures shown
• an AP projection of the elbow joint, distal arm, and proximal forearm is presented
Evaluation criteria
• proper collimation
• radial head, neck, and tuberosity slightly superimposed over the proximal ulna
• elbow joint open and centered to the CR
• no rotation of humeral epicondyles
• soft tissue and bony trabecular detail
Lateral elbow
Importance of flexing the elbow 90 degrees:
1) the olecranon process can be seen in profile
2) the elbow fat pads are the least compressed
In partial or complete extension, the olecranon process elevates the posterior elbow fat pad and simulates joint pathology
- 8 x 10 inch IR
- patient at the end of the radiographic table low enough to place humerus and the elbow joint in the same plane
Position of part
• from the supine position, flex the elbow 90 degrees and place the humerus and forearm in contact with the table
• center the IR to the elbow joint. Adjust the elbow joint so that its long axis is parallel with the long axis of the forearm. Elevate wrist as necessary
• adjust the IR diagonally to include more of the arm and forearm
• to obtain a lateral projection of the elbow, adjust the hand in the lateral position and ensure that the humeral epicondyles are perpendicular to the plane of the IR
• shield
Central ray
• perpendicular to the elbow joint, regardless of its location on the IR
Collimation
• 3 inches proximal and distal to the elbow joint
Structures shown
• the lateral projection shows the elbow joint, distal arm, and proximal forearm
Evaluation criteria
• evidence of proper collimation
• elbow joint open and centered to the CR
• elbow in a true lateral position; superimposed humeral epicondyles; radial tuberosity facing anteriorly; radial head partially superimposing the coronoid process; olecranon process in profile
• elbow flexed 90 degrees
• bony trabecular detail and any elevated fat pads in the soft tissue at the anterior and posterior distal humerus and the anterior proximal forearm
AP oblique, medial rotation, elbow
- 8 x 10 IR
- patient seated at the end of the radiographic table with the arm extended and in contact with the table
Position of part
• extend the limb in position for an AP projection, and center the midpoint of the IR to the elbow joint
• medially(internally) rotate or pronate the hand, and adjust the elbow to place its anterior surface at an angle of 45 degrees. This degree of obliquity usually clears the coronoid process of the radial head
• shield
Central ray
• perpendicular to the elbow joint
Structures shown
• 3 inches proximal and distal to the elbow joint and 1 inch on the sides
Evaluation criteria
• proper collimation
• elbow joint open and centered to the central ray
• 45 degree medial rotation of elbow
Coronoid process in profile
Elongated medial humeral epicondyle
Lina superimposed by the radial head and neck
• trochlea
• olecranon process within the olecranon fossa
• soft tissue and bony trabecular detail
AP oblique, lateral rotation, of elbow
- 8 x 10 IR
- patient seated at end of table with arm extended and in contact with the table
Position of part
• extend the patients arm in position for an AP projection, and center the midpoint of the IR to the elbow joint
• rotate the hand laterally (externally) to place the posterior surface of the elbow at a 45 degree angle. When proper lateral rotation is achieved, the patients first and second digits should touch the table
• shield
Central ray
• perpendicular to the elbow joint
Collimation
• 3 inches proximal and distal to the elbow joint and 1 inch on the sides
Structures shown
• the image shows an oblique projection of the elbow with the radial head and neck projected free of superimposition of the ulna
Evaluation criteria • proper collimation • elbow joint open and centered to the central ray • 45 degree lateral rotation of elbow Radial head, neck, and tuberosity projected free of the ulna Elongated lateral humeral epicondyle • capitulum • soft tissue and bony trabecular detail
Axiolateral, Doyle method, elbow
- 8 x 10 IR
- patient seated at end of table/ supine for imaging trauma
Position of part
• humerus, elbow, and wrist joints on same plane
• pronate hand and flex elbow 90 degrees to show the radial head or 80 degrees to show the coronoid process
• center the IR to the elbow joint. Elevate wrist as necessary
• shield
Central ray
Radial head:
• directed toward the shoulder at an angle of 45 degrees to the radial head; BR enters the joint at mid-elbow
Coronoid process
• directed away from the shoulder at an angle of 45 degrees to the coronoid process; central ray enters the joint at mid-elbow
Collimation
• 3 inches proximal and distal to the elbow joint
Structures shown
• shows an open elbow joint between the radial head and capitulum or between the coronoid process and trochlea with area of interest in profile. Used to show pathological processes or trauma in the area of the radial head and coronoid process.
Evaluation criteria
Radial head
• proper collimation
• open joint space between radial head and capitulum
• radial head, neck, and tuberosity in profile and free from superimposition with the exception of a small portion of the coronoid process
• humeral epicondyles distorted owing to central ray angulation
• radial tuberosity facing posteriorly
• elbow flexed 90 degrees
• soft tissue and bony trabecular detail
Coronoid process
• open joint space between coronoid process and trochlea
• coronoid process in profile and elongated
• radial head and neck superimposed by ulna
• elbow flexed 80 degrees
• soft tissue and bony trabecular detail
