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TECHNICAL ASPECTS

A moving or a stationary grid must be used. Relatively high kV is used, range is (80 - 95) KVp,

(95 -100) kVp for lateral L/S) to increase exposure latitude and reduces patient’s dose. All part supports and pads mentioned are radiolucent. The anode heel-effect must be observed, with anode at the head side (a wedge-filter

or graduated screens can be used instead) to produce overall uniform spine density. Radiosensitive areas must be well covered by shields. Collimation must be strictly applied in all projections to improve image contrast and reduce

patient’s dose and amount of scatter. Optimal density and contrast are necessary for an optimal image quality.

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AP thoracic (dorsal) spine B

AP thoracic (dorsal spine): For #s and pathology (compression, kyphosis, and subluxation).

Patient supine with head under anode side to observe the heel-effect, both knees and hips flexed and arms stretched by the side. Exposure at end of arrested expiration to reduce volume

of air in thorax for more uniform density of whole dorsal vertebrae.

Film: HD 35x43 cm, lengthwise.

CP: T7 1 - 2 inches ( 3 – 5 cm) below the sternal angle, or 3 -4 inches ( 8 – 10 ) cm below jugular notch) as for the PA chest.

CR: 90 Vertically to the thoracic spine

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Lateral thoracic (dorsal) spine B

Lateral thoracic spine: For pathology (compression, kyphosis, or subluxation).

Patient in a lateral recumbent, both knees flexed and arms stretched at right angles, waist supported, anode heel-effect should be well observed. Exposure at end of arrested expiration, or during quiet breathing using low mA and long exposure time (3 - 4 s) to diffuse the lung and ribs shadows. A lead blocker sheet near patient’s back helps stop scatter rays from reaching the film, thus improves image quality.

Film: HD 35x43 cm , lengthwise.

CP: T7

CR: 90 Vertically to the thoracic spine

Intervertebral joint

thoracic vertebral bodies

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PAO (or APO) thoracic spine S

Zygapophyseal joints of the thoracic spine.

Patient in a lateral recumbent or in lateral erect, body rotated 20 from true lateral, arm nearest couch must be down, arm nearest tube must be up and forward. Exposure at end of suspended

full expiration.

Film: HD 35x43 cm . Lengthwise .

CP: T7 .

CR: 90 to film center.

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AP lumbar spine B

For #s, pathology (scoliosis and neoplastic processes of the thoracic spine).

Patient supine or erect, knees flexed with soles of feet on the couch top, arms at the sides or on the chest, exam can be done in the erect position, exposure must be during a quiet breathing at low mA and long exposure time to diffuse colonic gas shadows. Exposure at end of full expiration.Film: HD 35x43 cm . Lengthwise .

CP: Large film (35x43) cm: L4 – L5 (level of iliac crest). Small film (30x35) cm: L3 (level of lower costal margins).

CR: 90 to film center.

spinous process

L 5

sacroiliac joint

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Lateral Lumbar Spine B

Lateral lumbar vertebral bodies, spinous processes, L5 – S1 junction, and sacrum. Rules-out compression # of lumbar bodies.

Patient in a lateral recumbent, knees flexed, support between knees and ankles, pad under the waist, a piece of lead rubber behind the lumbar region on couch top to improve contrast (by absorbing scatter). Exposure at end of arrested expiration.

Film: HD 35x43 cm

CP: Large film: L4 – L5 (level of iliac crest). Small film: L3 (level f lower costal margins).

CR: 90 V to center of film

NB/ Lateral for trauma can be done with patient in (supine decubitus), with same CP and horizontal beam.

L5-S1 joint

sacrum

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AP axial lumbosacral joint (L5-S1) S

For pathology of AP (L5 – S1) articulation and AP sacro - iliac joints.

Patient supine, legs extended, both knees flexed slightly over support, arms at sides or on the chest.

Film: HD 18x24 cm crosswise

CP: Level of ASIS.

CR: 30 cephalic (males), 35 cephalic (females).

L5-S1 joint

sacroiliac joint

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Lateral lumbosacral spine (L5 – S1) B

For lat L5 – S1 joint space .

Patient in a lateral recumbent, the knees flexed, support between knees and the ankles, pad under the waist, rubber sheet behind the lumbar region.Film: HD 18x24 cm lengthwise .

CP: 1.5 inch ( 4 cm ) inferior to iliac crest, 2 inches ( 5 cm ) posterior to ASIS .

CR: 90 V to film center (with sufficient waist support), 5-10 caudal for waist (with no support).

NB/ Close collimation is necessary because of the high amount of secondary radiation produced in this view.

L5-S1 joint

sacrum

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AP axial sacrum B

AP sacrum (not foreshortened), S.I. joints, and L5 – S1junction.

Patient supine, legs extended, support under the knees.Exposure during arrested expiration.

Film: HD 24x30 cm

CP: Midway between level of the symphysis pubis and ASIS.

CR: 15 cephalad.NB/ For lateral sacrum: Patient in true lateral recumbent, CR 90

vertically 5 cm anterior to posterior sacral surface at level of ASIS.

sacroiliac joint

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AP axial coccyx B

For pathology of the coccyx. Urinary bladder should beEmptied before this examination Cleansing enema mustAlso be done to clean the colon of fecal material.

Patient supine, legs extended, support under the kneesFilm: HD 24x30 cm

CP: 2 inches 5 cm superior to the symphysis pubis.

CR: 10 caudad.

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Lateral coccyx B

For pathology of the coccyx. (urinary bladder and the colon should be emptied before examination from their contents. Cleansing enema is used for the colon.

Patient in a lateral recumbent, knees flexed, support under the waistFilm: HD 18x24 cm

CP: 5 cm distal to level of ASIS, and 5 cm anterior to posterior surface of sacrum and coccyx.

CR: 90 V to film center.

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TABLE 4 (Exposure Factors)

PROJECTION kVp mAs AP Thoracic Spine 90 7

Lateral Thoracic Spine 80 50

AO Thoracic Spine 80 26

AP Lumbar Spine 80 15

AP Axial Lumbosacral Spine Joint (L5 – S1) 80 20

Lateral Lumbosacral Spine Joint (L5 – S1) 100 50

Lateral Lumbar Spine 90 65

AO Lumbar Spine 85 15

Layout and design by A Musa, Department of Radiological Sciences, Faculty of Applied Medical Sciences, King Saud University, Riyadh, Copyright 2003 A Musa

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TABLE 4 (Exposure Factors)

PROJECTION kVp mAs AP Axial Sacrum 80 15

AP Axial Coccyx 80 15

Lateral Coccyx 90 55

Layout and design by A Musa, Department of Radiological Sciences, Faculty of Applied Medical Sciences, King Saud University, Riyadh, Copyright 2003 A Musa