Principles of Radiographic Imaging Technique

PACEMAN


P - Positioning….Patient correctly positioned?


A - Area…….Area of interest covered?


C - Collimation & Centering…..Image properly collimated?


E - Exposure….. Exposure Index (EI)? Correct contrast, density and penetration?


M - Marker…..Radiographic marker? Correct one?


A - Artefact…. Artefacts aka jewellery. metal


N - Need for repeat….Need anything repeated?


Positioning - DP Hand


● Patient seated at the end of the table with elbow flexed at 90 degrees
● Patient’s legs must not be placed under the table for radiation purposes
● A sheet of lead-rubber can be positioned over the lower abdomen and thighs to cover the gonads (depends
on protocol)
● Forearm should be rested on table so the palmar hand can come into direct contact with the imaging
receiver
● The fingers should be extended and slightly separated
● Remove artefacts before the examination
● If using Direct Radiography (DR) the hand should be placed close to the centre of the cassette
● If using Computed Radiography (CR) then a 24x30 cassette is chosen, Two projections on one cassette
○ Used in landscape position with one half used for each of 2 exposures
● Palmar surface in contact with image receiver (IR)
● Central Ray → Vertical to IR, centred on 3rd metacarpophalangeal joint
● Distance → 100cm FFD/SID
● Collimate → All four sides of hand and carpal bones


Positioning - Oblique Hand


● From the DP position rotate the entire hand and wrist laterally 45 degrees
○ Flex the fingers slightly so thumb and finger tips touch IR (Make OK sign and then slightly
separate)
● Central Ray → Centred to 2nd/ 3rd metacarpophalangeal joint
● Distance → 100cm FFD/SID
● Collimate → All 4 sides to outer margins of hand and wrist




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,Positioning - Lateral Hand


● From the DP position rotate the entire hand and wrist laterally 90 degrees
● Fingers should be extended as much as possible
● Thumb should be abducted so as not to overly the fingers
● Central Ray → Head of 2nd metacarpophalangeal joint
● Distance → 100cm
● Collimate → All 4 sides to outer margins of hand and wrist


Positioning - DP Finger


● Same as DP Hand
● The affected finger should be extended
● Central Ray → Relevant metacarpophalangeal joint or interphalangeal joint
● Distance → 100cm FFD/SID
● Collimation → Include adjacent finger to help identify finger and identify abnormality


Positioning - Lateral Finger


● 3rd-5th → Fingers extended, positioned with its medial aspect in contact/ close to the IR
● Use a foam pad to separate fingers if patient unable
● 2nd → Patient forearm internally rotated, extended elbow
● Central Ray → Relevant metacarpophalangeal or proximal interphalangeal joint
● Distance → 100cm FFD/ SID


Positioning - DP or PD Thumb


● Patient is seated parallel to the x-ray table or patient facing away from the table
● A sheet of lead-rubber MUST be positioned over the lower abdomen and thighs to cover the gonads
● The arm should be extended across the table and internally rotated until the posterior aspect of the thumb
comes into contact with IR
● Centre Ray → First metacarpophalangeal joint
● Distance → 100cm FFD/ SID
● Collimate → Trapezium and all 4 sides of thumb


Positioning - Lateral Thumb


● Start with the hand pronated (palm against the IR) and thumb abducted
● With the fingers slightly arched the hand should be rotated internally until the thumb is in true lateral position
● Centre Ray → First metacarpophalangeal joint
● Distance → 100cm FFD/ SID
● Collimate → Trapezium and all 4 sides of thumb




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, Positioning - DP Wrist


● Legs must not be placed under the table
● Affected arm abducted and extended across the Image Receiver (IR)
● The elbow is flexed 90 degrees and anterior aspect of forearm placed in contact with IR and wrist direct
contact
● Radial and ulnar styloid processes are equidistant from the IR
● Fingers should be relaxed
● Centre ray
○ Centre midway between the radial and ulnar styloid processes
● Distance → 100cm FFD/SID
● Collimate
○ Include metacarpal-phalangeal joints, carpals, metacarpals and the distal third of the radius and
ulna
○ Soft tissues outline of the wrist


Positioning - Lateral Wrist


● Affected arm abducted and extended across the IR with elbow flexed at 90 degrees
● The forearm should be externally rotated through 90 degrees until the medial aspect of the wrist comes into
contact with the IR
● Further external rotation (5 degrees) may be necessary to superimpose the radial and ulnar styloid
processes
● Central Ray
○ Centre to the radial styloid process
● Distance → 100cm FFD/SID
● Collimate
○ Include metacarpal-phalangeal joint, metacarpals, carpometacarpal joints, carpals,
radio/ulnar-carpal joint, distal radio-ulnar joint, distal third of radius and ulna
○ Soft tissues dorsal and palmar


Positioning - DP Ulnar Deviation (Scaphoid)


● The elbow is flexed to about 90 degrees and anterior aspect of forearm placed in contact with IR with the
wrist in direct contact
● Radial and ulnar styloid processes are equidistant from the IR
● From the DP wrist position the hand should be abducted - flexed towards the ulna (opens up the joint
spaces around the scaphoid)
● Central Ray
○ Centre midway between the radial and ulnar styloid processes
● Distance → 100cm FFD/SID
● Collimate
○ All 4 sides to include the carpal region and wrist



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