Basic Positioning examination techniques

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Basic Positioning / examination techniques
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Displaying radiographs

• Why does it matter?
• Generally in accordance with the radiologists
  preference.
• X-rays should be looked at, as if you are looking
  at the patient. In true anatomical position.
• Left side on your right.
• Anatomical MARKERS must be displayed.
• All required anatomy must be displayed.
• Chest Lung apices at top.
• Abdomen Diaphragm at top.
• Shoulder
• Hands and feet
• Limbs
• Skull

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Radiographic positions

• Formal descriptors of radiographic positions MUST
  be used in all assessment items (eg examinations,
  assignments)
• Abbreviations (eg AP, LAO) may be used only after
  they have been defined.
• Slang and shorthand descriptors WILL NOT be
  accepted (eg PA oblique, shoot through
  lateral)
• Radiographic POSITION describes the relationship
  of the patients anatomy to the primary beam and
  the image receptor.
• Radiographic PROJECTION describes the anatomical
  relationships as demonstrated on the image
  receptor.

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Anteroposterior/posteroanterior
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Left anterior oblique LAO
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Decubitus
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Axial positions

• Axial positions describe the path of the primary
  beam parallel to, or at an acute angle to, the
  long axis of the anatomy, normally bones (eg
  axial patella, axial calcaneum). The direction of
  travel of the primary beam may be either from
  superior to inferior or inferior to superior.

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Tangential positions

• Tangential positions describe the path of the
  primary beam along a tangent to the radius of a
  curved bone. Usually only applied to skull
  projections.

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Patients needing special care

• Breathing difficulties
• Stroke (CVA)
• s
• Joint replacements
• Spinal trauma
• Paralysed
• Cardiac complaint
• Geriatric/paediatric

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Motion in RadiographyArtefacts

• Involuntary muscles
• Heart
• GI system
• Spasm
• Voluntary muscles
• Nervousness
• Fear
• Excitability
• Pain
• Breathing

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Restraints and Immobilisation

• Not always comfortable
• Not always confident
• Sponges
• Sandbags
• Sheets
• Velcro straps
• Belts
• Piggostats

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Positioning for safety and comfort

• Support / padding
• Skin care
• Timing
• Touch
• communication

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Patient instructions

• Communication
• What do you need to communicate
• Lifting and handling
• Pre-exposure instructions
• Exposure technique
• Adaptation of exposure
• Post-exposure instructions

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Structural relationship in positioning

• As a radiographer you will have to know the
  structural relationship of the organs and anatomy
  within the body.
• And a thorough knowledge of their relationship
  when the patient is in different positions, or
  has different pathologies.
• Example diaphragm.
• Erect lies in an oblique plane on the level of
  the sixth costal cartilage anteriorly and tenth
  posteriorly
• Supine is situated 4-12 centimetres more
  superior to that when erect. And this will be
  more with bigger patients
• Prone is situated 4-12 centimetres inferior to
  that of the erect, the depression of the
  diaphragm will be greater in thin patients.

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Artifacts

• Why is this a consideration?
• Artefact
• Basic analysis
• Unwanted marks on x-ray film
• Frustrating to identify and trouble shoot.
• Positive density x-ray artifacts
• Dark marks
• Negative density x-ray artifacts
• Light marks
• Transmitted density x-ray artifacts
• May be positive or negative in nature.
• Usually occur in processing
• Reflected density x-ray artifacts
• Most commonly wash step related.
• Best viewed reflecting light off film

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Artifacts / film screen

• Scratches
• Dust
• Light leak
• Static build up
• Back to front

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Artifacts / Patients clothing

• Why is this a problem?
• Some things to be aware of
• Necklaces
• Bras
• Wet long hair
• Dentures
• Nipples
• Tattoos
• Scar tissue
• Wet plaster
• Bandages
• Pockets
• Strange hiding places for things.

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Identification of radiographs

• Get in a habit of checking the x-ray details
  before you bag the films.
• Each and every x-ray must include
• Patients name or medical records number (MRN)
• The date
• The correct anatomical marker
• This includes right, left, erect, supine, prone
  etc
• The identity of the institution where the
  procedure was performed.

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Film placement

• This is an important factor in good radiography.
• Region of interest is at the centre of irradiated
  area/film.
• Central beam also projected at centre of film
• Diagnostics vs. aesthetics
• Always have to include both joints of long bones.

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Direction of central beam

• Always centred to the film
• Always perpendicular to film
• General goal is to have central beam at right
  angles to structure of interest.
• The central beam is angled through the region of
  interest
• Avoid superimposition
• Avoid stacking a curved structure on itself
• Project through joints

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Collimation of x-ray beam

• Must use collimation as a radiation safety
  mechanism. As well as a image quality tool.

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Gonad shielding

• When should this be used?
• The patients gonads may be irradiated when
  performing what types of examinations?
• Lead rubber, lap gown, or full gown may be useful.

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Radiographic routine

• Read request
• Room preparation
• Patient reception
• Patient preparation
• Conduct of examination
• Patient aftercare
• Film/image processing
• Patient discharge
• Reporting and filing

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Radiographic techniqueThe following points must
be included in a full description of the
radiographic projection

• Full anatomical name of projection
• Patient position
• Centering point of primary beam
• Angulation of primary beam
• Patient immobilisation required
• Radiation protection for patient

• Film/screen combination
• Film size
• Collimation
• Grid/bucky required
• Exposure factors
• Patient respiration phase during exposure
• Major anatomical landmarks and relationships seen
  on a correctly positioned radiograph

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Image production

• Primary radiation, photons
• Remnant radiation
• Scatter radiation
• Attenuation
• Radiolucent structures
• Radiopaque structures

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Film screen radiography

• Latent image
• Image is stored in the emulsion until processed.
• Intensifying screens
• Light production
• Film/screen combinations
• Single emulsion / single screen
• Double emulsion / two screens

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Geometric qualities

• Recorded detail
• Motion
• Object unsharpness
• Focal spot size
• Source to image distance
• Penumbra
• umbra
• Object to image distance
• Material unsharpness
• Distortion

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TEST

• Next lecture i.e. 17th may
• Here in lecture room again
• Short answer questions
• Maybe some labelling
• Everything we have covered so far