Projectional radiography

  Projectional radiography or plain film radiography is the practise of producing 2D X-ray images. Typically most body parts being x-rayed, have two 'projections' taken, usually at right angles to each other. This is for two reasons. First that many fractures are only visible in one plane, which exact plane is unknown to the radiographer until the images is taken. Secondly to assess alignment of fractures and spatial position of foreign bodies. Gathering as much information as possible is very important as it can mean the difference between a POP cast and surgery. Mammography and dental radiography also come under the category of projectional radiography, but these topics are too complex to include in this article. See Mammography and Dental radiography for the full article.

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Clinical applications of projectional radiography

Projectional radiography is typically used to detect:

Boney anomalies

• Fractures
• Dislocations
• Arthritis
• Benign and Malignant Tumours
• Scoliosis
• Other Bone Conditions i.e.Scleroderma and Osteomyelitis

Soft tissue anomalies

• Chest Pathology
• Acute Bowel Obstruction
• Bowel Perforations
• Foreign body

Divisions of the skeleton

The human skeleton is divided into two categories:

• Axial skeleton
• Appendicular skeleton

Axial skeleton

• Skull and Facial Bones
• Chest
• Cervical Spine
• Thoracic spine
• Lumbar spine
• Sacrum and Coccyx
• Abdomen

Appendicular skeleton

• Shoulder Girdle
• Humerus
• Elbow
• Radius and Ulna
• Wrist
• Hand
• Fingers / Thumb
• Pelvic girdle
• Femur
• Knee
• Tibia and Fibula
• Ankle
• Calcaneum
• Foot / Toes

Projectional radiography terminology

NOTE: The word 'view' is often used erroneously to describe a radiographic projection. As my old Radiography lecturer once intoned to my class; 'a view is what you see out of the window'

• AP - Antero-Posterior
• PA - Postero-Anterior
• Lateral - Projection taken with the central ray perpendicular to the midsaggital plane
• Oblique - Projection taken with the central ray at an angle to any of the body planes
• Flexion - Joint is radiographed while in flexion
• Extension - Joint is radiographed while in extension
• Stress Views - Typically taken of joints held in a 'stressed' position. Test of stability.
• HBL or HCR - Horizontal Beam Lateral or Horizontal Central Ray. Used to obtain a lateral projection usually when patients are unable to move.
• Prone - Patient lies on their front
• Supine - Patient lies on the back
• Decubitus - Patient lies on their side
• OM - Occulomeatal, an imaginary positioning line extending from the outer canthus of the eye to the external auditory meatus
• Cranial - Tube angulation towards the head
• Caudal - Tube angulation towards the feet

Equipment Used in Projectional Radiography

• Ceiling or Floor Mounted X-ray tube
• Height adjustable table
• Bucky or Digital Detector
• User Interface
• Image Receptor - Film / Screen Cassette or CR Plate / DR Detectors
• Processor or Image Reader
• Chest Stand

Differences around the world

Routine projections used in the UK

• Chest - PA Only. Lateral on request by a Radiologist
• Abdomen - AP Only. Decubitus on special request
• Cervical Spine - AP and Lateral. Peg projection with trauma only. Obliques and Flexion and Extension on special request
• Thoracic Spine - AP and Lateral
• Lumbar Spine - AP and Lateral +/- L5/S1 view. Obliques and Flexion and Extension requests are rare
• Pelvis - AP only. SIJ projections (prone) on special request
• Hip - AP and Lateral
• Skull - None. Patient goes to CT.
• Sinus - OM with open mouth
• Facial Bones - OM and OM 30°
• Shoulder - AP and Lateral Scapula or Axillary Projection. Other Special projections available on request
• Clavicle - AP and AP Cranial
• Humerus - AP and Lateral
• Elbow - AP and Lateral. Radial head projections available on request
• Radius and Ulna - AP and Lateral
• Wrist - AP and Lateral
• Scaphoid - AP with Ulna deviation, Lateral, Oblique and AP with 30° angulation
• Hand - AP and Oblique
• Fingers / Thumb - AP and Lateral
• Femur - AP and Lateral
• Knee - AP and Lateral. Intra Condular projections on request
• Patella - Skyline Projection
• Tibia and Fibula - AP and Lateral
• Ankle - AP and Lateral
• Calcaneum - Axial and Lateral
• Foot / Toes - AP and Oblique

Routine projections used in the US

Routine projections used in Australia:

See also

• Radiography
• Medical imaging
• X-ray
• Radiologic technologist
• Computed radiography
• Digital radiography
• Tomography
• Anatomical terms of location

References

• 1.The Pocketbook of Radiographic Positioning by Ruth Sutherland
• 2.Bones and Joints: A Guide for Students by Christine Gunn
• 3.Imaging Atlas of Human Anatomy by Jamie Weir, Peter H. Abrahams
• 4.Nice Guidelines
• 5.The Human Skeleton