rad tech-upper extremity

kVp used

speed. low-mid range of 60-80 on digital systems

mAs used

amount of radiation. varies depending on system. Looking for good trabecular bony details; and soft tissue margin visualization

SID

subject to image distance, 100-115cm (40-46 inches)

PA Finger ( 2nd-5th Digit)

patient position:

• Sitting at side or end of table

• Arm (humerus) is abducted

• Elbow is flexed 90 degrees

• Forearm is resting on table

part position:

• Finger is not medially or laterally rotated

• Fingers are slightly spread to prevent soft tissue overlap

CR:

• Perpendicular to IR

• Centered to proximal IP joint

Collimation:

• X-ray beam collimated to include entire finger and at least ⅓ of the metacarpal

Evaluation Criteria for PA Finger

• Entire finger and minimum ⅓ of metacarpal demonstrated

• Some technologists will choose to include entire metacarpal on image

• Center field at PIP joint

• No rotation of phalanges

• Equal concavity of both sides of phalanges

• Equal amounts of soft tissue demonstrated on both sides of bone

• IP and MCP joints are open spaces

PA 45 °Oblique Finger ( 2nd-5th Digit)

Patient Position

•  Sitting at side or end of table

•  Arm (humerus) is abducted

•  Elbow is flexed 90 degrees

•  Forearm is resting on table

Part Position

•  Finger is rotated 45 degrees externally (thumb side up)

•  2nd digit can be medially rotated instead

•  Fingers spread slightly

•  Finger remains parallel to image receptor

•  Can use a positioning sponge

CR

• X-ray beam collimated to include entire finger and at least ⅓ of the metacarpal

Evaluation Criteria for PA 45° Oblique Finger

• Entire finger and MCP joint demonstrated

• Increased concavity of lateral (thumb side) aspect of phalange

• Decreased concavity of other aspect

• Note: opposite will be true for the 2nd digit if it was rotated internally rather than externally

• Center field at PIP

• IP and MP joints are open spaces

• Soft tissue demonstrated

Lateromedial or Mediolateral- Finger ( 2nd-5th Digit)

Patient Position

•  Sitting at side or end of table

•  Arm (humerus) is abducted

•  Elbow is flexed 90 degrees

•  Forearm is resting on table

Part Position

•  Affected finger is straight with other fingers placed in a loose fist

•  May need a positioning aide to keep affected finger straight

•  Affected finger in a lateral position (“side- on”) and parallel

•  2nd finger may be positioned “thumb side” against the IR (mediolateral)

•  3rd-5th usually positioned with medial aspect of hand against the IR (5th finger against IR)

CR

•  Perpendicular to IR

•  Centered to proximal IP joint

Collimation

•  X-ray beam collimated to include entire finger and at least ⅓ of the metacarpal

Evaluation Criteria for Lateral Finger

• Entire finger and MCP joint demonstrated

• CR centered at PIP

• Collimation includes entire finger and at least MCP joint

• True lateral position

• Anterior aspect is concave

• Posterior aspect is straight or slightly convex

• Digit parallel to IR

• IP and MP joints are open spaces

AP Thumb ( 1st Digit)

Patient Position

• Sitting facing the table

• Arm is extended and in extreme internal rotation

Part Position

• Posterior surface ( back) of thumb is in contact with the IR

• Fingers may need to be held back by other hand

CR

• CR is perpendicular to first MCP joint

Collimation

• Collimation to include entire thumb and trapezium

PA thumb

PA Projection: Alternative to AP if required

Evaluation Criteria for AP (PA) Thumb ( 1st Digit)

• Entire thumb demonstrated (including first CMC joint)

• No soft tissue overlapping MCP

• Center field at first MCP joint

• Must include trapezium

• No rotation of phalanges

• Equal concavity and soft tissue

PA 45° Oblique Thumb ( 1st Digit)

Patient Position

• Same as AP thumb or same as finger

• Sitting facing table or alongside table

Part Position

• Hand is placed palm down on the IR (pronated)

• This naturally places the thumb in a 45 o oblique

• Hand must be flat with no flexion in the fingers

• Thumb is slightly abducted

CR

• CR is perpendicular to 1st MCP joint

Collimation

• Collimate to include all of thumb and trapezium

Evaluation Criteria for PA 45° Oblique Thumb ( 1st Digit)

• Entire thumb demonstrated including trapezium and CMC joint

• Joints partially open as in 45° oblique

• Increased concavity of phalanges on side facing fingers

• Center of field at first MCP joint

Lateral Thumb ( 1st Digit)

Patient Position

• Same as PA & Oblique

Part Position

• Place hand flat on IR ( same as oblique) and flex the fingers to “roll” thumb to a lateral position

• Hand may be positioned in a loose fist as well

• Rotate hand medially to place thumb in a true lateral

• Thumbnail is the profile

• Abduct thumb slightly

CR

• Center to 1st MCP

Collimation

• Collimate to include entire thumb and trapezium

Evaluation Criteria for Lateral Thumb ( 1st Digit)

• Entire thumb demonstrated including trapezium

• Minimal overlap of bases of 1st and 2nd metacarpals

• Center of field at first MCP joint

• Increased concavity of phalanges on anterior (finger) side

• Decreased concavity on posterior side

PA Hand

Patient Position

•  Sitting at side or end of table

•  Humerus abducted; elbow flexed 90 degrees

•  Forearm resting on table

Part Position

•  Hand is placed palm down on IR ( pronated)

•  Fingers slightly spread

•  No rotation of hand

CR

• Centered to 3rd MCP joint

Collimation

• Include all carpals, metacarpals, phalanges and distal portion of radius and ulna

Evaluation Criteria for PA Hand

• Entire hand and carpals demonstrated

• Center of field at 3rd MCP joint

• MCP and IP joints are open

• Equal concavity of phalanges and metacarpals

• Slight overlap of bases of the 2nd to 5th metacarpals

• No overlap of heads of the 2nd to 5th metacarpals

• Minimum of 2.5cm (1”) of radius & ulna included

PA (external) 45 degree Oblique Hand

Patient Position

• Sitting at side or end of table

• Arm (humerus) is abducted

• Elbow is flexed 90 degrees

• Forearm is resting on table

Part Position

• Hand is obliqued 45 degrees externally ( pinky down)

• Fingers should be kept parallel to IR

• When fingers are not of interest; fingers may be flexed and placed on IR

CR

• Centered to 3rd MCP joint

Collimation

• Include all carpals, metacarpals, phalanges and distal portion of radius and ulna

Evaluation Criteria for PA 45 degree Oblique Hand

• Entire hand and carpals demonstrated

• Midshafts of metacarpals should not overlap

• Heads of 3rd,4th,5th metacarpals are slightly overlapped

• Minimal overlap of heads of 2nd & 3rd

• MCP and IP joints are open ( if fingers were kept parallel)

Lateral ( fan) Hand-Lateromedial Projection

Patient Position

•  Sitting at side or end of table

•  Arm (humerus) is abducted

•  Elbow is flexed 90 degrees

•  Forearm is resting on table

Part Position

•  Hand is placed in a lateral position with the medial aspect ( pinky side) of hand on the IR

•  Fingers & thumb are spread out like a “fan”

•  Phalanges are kept parallel to IR

•  Metacarpals are superimposed

•  ** Use metacarpals to judge accuracy of positioning not the radius and ulna

CR

• CR centered to 2nd MCP

Collimation

• Include all carpals, metacarpals, phalanges and distal portion of radius and ulna

Evaluation Criteria for Lateral Hand

• Entire hand and carpals demonstrated as well as at least 2.5 cm ( 1”) of radius & ulna

• Centered at second MCP joint

• Fingers equally separated

• Metacarpals superimposed

• Radius and ulna superimposed or ulna is slightly posterior

Lateral Hand- Extension/Slight Flexion

• Same basic positioning and centering as “fan” lateral

• Fingers are extended and superimposed

• May be used for detection of foreign bodies or to better visualize anterior/posterior displacement fractures of the metacarpals

• Fingers can be flexed slightly if extension is too painful

• Thumb is in a PA

Bilateral AP Oblique hands “ Ball Catchers”

- Special projection for early detection of rheumatoid arthritis and fractures at the base of the 5th metacarpal

- Both hands are imaged together

- This projection is usually substituted for the PA oblique

Patient Position

• Sitting facing the table

Part Position

•  Both hands ;with posterior aspect against the IR

•  Hands internally obliqued 45⁰

•  Fingers extended ( can be slightly flexed)

•  Thumb slightly abducted to prevent superimposition over metacarpals

•  Note: this can be difficult for patients with advanced disease

CR

• Centered between hands @ level of MCP’s

Collimation

• Same as PA /PA Oblique

Evaluation Criteria for “ Ball Catchers”

• Bilateral hands in 45° oblique position

• Midshafts of second to fifth metacarpals and base of phalanges not overlapped

• Thumb not superimposed over metacarpals

• MCP joints should open

PA Wrist

Patient Position

•  Sitting alongside or end of table

•  Humerus abducted & elbow flexed 90 degrees

•  Elbow, forearm, wrist and hand are resting on table

•  Shoulder and forearm/wrist should be at the same level

•  May need to raise the table or support the IR on a sponge etc

Part Position

•  Wrist is placed on the IR with hand pronated

•  Mid-carpal area centered to the IR

•  Arch hand slightly(10-15 o ) to place carpal area in close contact with the IR

CR

•  Perpendicular to IR

•  Centered to mid carpal area

Collimation

•  include all carpal bones, distal radius & ulna and proximal metacarpals

• 1/3 of metacarpals and 1/3 of forearm included

Evaluation Criteria for PA Wrist

• Distal radius/ ulna and carpals demonstrated

• Ulnar styloid process in profile

• If humerus is not abducted & elbow flexed: the ulnar styloid process will not be in profile

• Open (or near open) radioulnar joint

• Center of field at midcarpals

• Long axis of 3rd metacarpal in line with long axis of forearm

• No rotation

• Exposure factors

• Good soft tissue

• Should demonstrate scaphoid fat stripe

scaphoid fat stripe

looks black, sign of fracture or dislocation. On PA and oblique wrist projections

PA 45 degree Oblique Wrist

Patient Position

• Same as PA Wrist

Part Position

• Hand is pronated and wrist is rotated 45 o laterally

• Thumb side “up”

• Hand should be arched slightly

• Long axis of 3rd metacarpal in line with long axis of forearm

CR

• Centered to mid-carpal region

Collimation

• Same as PA Wrist

Evaluation Criteria for PA 45 degree Oblique

• Distal radius, ulna, and carpals demonstrated

• Radius & ulna partially superimposed

• slight overlap of metacarpals

• Center of field at midcarpals

• Trapezium and trapezoid seen in its entirety

• Scaphoid is minimally superimposed by trapezoid & capitate

• Exposure factors: soft tissue + bony detail

• 3rd metacarpal lines up with middle of wrist

Lateral Wrist-Lateromedial Projection

Patient Position

• Same as PA & PA Oblique Wrist

Part Position

•  Wrist is placed on the IR in a true lateral with thumb side up ( lateromedial)

•  Use the radius & ulna to determine “true” lateral ; not the hand

•  First metacarpal is parallel to forearm

CR

• Centered to mid-carpal region

Collimation

• Same as PA Wrist

Evaluation Criteria for Lateral Wrist

• Distal radius, ulna, and carpals demonstrated

• Radius and ulna are superimposed

• Metacarpals nearly all superimposed

• Ulnar styloid in profile posteriorly

• Distal margins of scaphoid and pisiform are aligned

• Center of field at midcarpals

• First metacarpal parallel to radius/ulna

• Exposure factors demonstrate the pronator fat stripe

pronator fat stripe

on prone/anterior side. Always present

FOOSH

fall on outstretched hand, often causes scaphoid fracture

why does a fractured scaphoid become more apparent after it occurs

it can cut off the blood supply. Also once bony callus starts to form

PA/PA Axial Scaphoid-Ulnar Deviation

 Patient is positioned same as PA wrist except hand is flat on IR

 Wrist is in ulnar deviation

• Forearm remains stationary

• Hand is deviated towards the ulna

• 1st metacarpal is aligned w/ radius

 CR centered to scaphoid

• 2cm distal & medial to radial styloid process

- Base of anatomical “snuff box”

 Collimation can be closer than for “regular” PA wrist

 CR may be angled toward the elbow

• 10-15 o or 20° (Stetcher Method)

Other Positioning Modifications for Scaphoid

• Clenched fist (done at QEH, make fist to straighten scaphoid, and ulnar deviate)

• Elevated Hand/Wrist

• Multiple CR angles

evaluation criteria for PA/PA Axial Scaphoid-Ulnar Deviation

 Scaphoid clearly seen without superimposition

• 10° to 15° CR angle (elongates scaphoid)

 Scaphoid fat stripe demonstrated

 1st metacarpal is aligned with the long axis of the forearm

•  Indicates proper ulnar deviation