Thoracic Spine - AP

Radiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Thoracic Spine - AP
Area Covered	C7 to L1
Pathology shown	Fractures, scoliosis/kyphosis, tumour, infection, congenital abnormality
Radiographic Anatomy	Thoracic Spine Radiographic Anatomy
IR Size & Orientation	35 x 43 cm Portrait
Film / Screen Combination	Regular (CR and DR as recommended by manufacturer)
Bucky / Grid	Moving or Stationary Grid
Filter	Decubitus filter over the superior thoracic spine when using film, not required with DR CR
Exposure	66 kVp 20 mAs or 66 kVp 20mA 1sec for breathing technique
FFD / SID	100 cm
Central Ray	Directed to T7 (to the midsaggital plane, midway between the jugular notch and the xiphoid process) Perpendicular to the IR
Collimation	Centre: To the midsaggital plane, midway between the jugular notch and the xiphoid process Shutter A: Open to include the hyoid bone Shutter B: Open approximately 10 - 12 cm to include the paraspinal soft tisues (this may need to be open wider in the case of scoliosis)
Markers	Superior and LateralMarker orientation AP
Shielding	Gonadal (check your department's policy guidelines)
Respiration	On suspended deep inspiration or gentle breathing for breathing technique
Positioning	The patient is supine on the table bucky, arms at their sides Align the midsaggital plane so it is in line with the midline of the IR Ensure there is no patient rotation Flexing the patient's knees up, with the soles of their feet flat on the table helps to reduce the curve of the lower back and is often more comfortable for the patient Position so that the top of the IR is approximately 5 cm above the shoulders
Critique PACEMAN	Positioning No rotation is evidenced by The spinous processes are seen in the midline of the vertebral bodies (see notes below) The pedicles are equidistant from the vertebral body edges (see notes below) Correct central ray angulation is evidenced by The intervertebral disc spaces are seen open (see notes below) The midsagittal plane is centred to the long axis of the film Area Covered C7 through to L1 Collimation Centre: To T7 Shutter A: Open to include C7 through to L1 Shutter B: Open to include the entire thoracic spine, including the soft tissue of the neck Exposure Bony trabecular patterns and cortical outlines are sharply defined The vertebral bodies, spinous and transverse processes and pedicles are distinguishable Soft tissues such as an air filled trachea are visualised
Special Notes	Determining the direction of rotation Using spinous process alignment: When the spinous processes are not seen in the midline of the vertebral bodies this usually indicates rotation of that part of the cervical spine. As the head is rotated in a particular direction, the spinous process tip will move in the opposite direction. For example, if the spinous process tip is closer to the left vertebral body edge, then the patient's neck is rotated so they are looking towards the right side. Using pedicle alignment: In an AP view the pedicles are seen laterally in the area between the transverse process and the vertebral body. With correct positioning the pedicles should be equidistant from the vertebral body edges. Example: If the right pedicle is more towards the midline of the vertebral body (it is rolled under/behind the vertebral body), indicating the patient is rotated so they are looking towards the right side. Demonstrating intervertebral disc spaces Successful demonstration of the intervertebral disc spaces is largely dependent on correct central ray angulation. Generally, the central ray is perpendicular to the film.