Sacrum & Coccyx Positioning

Question 1

What kvp is used for AP sacrum?

Answer 1

75-95

Question 2

What kvp is used for AP coccyx?

Answer 2

75-85

Question 3

What kvp is used for lateral sacrum?

Answer 3

90-100

Question 4

What kvp is used for lateral coccyx?

Answer 4

85-90

Question 5

What AEC cell is used for all sacrum and coccyx projection?

Answer 5

Center

Question 6

What are the essential projections for sacrum?

Answer 6

AP axial
Lateral

Question 7

What are the essential projections for coccyx?

Answer 7

AP axial
Lateral

Question 8

T/F
A patients urinary bladder should be emptied before imaging to improve visualization

Answer 8

True

Question 9

-supine
-MSP in midline of table
-ASIS equidistant from table
-legs extended
-15 degrees cephalad

Answer 9

AP axial sacrum

Question 10

What angulation is used for sacrum?

Answer 10

Supine
-15 degrees cephalad

Prone
-15 degrees caudad

*may be increased to 20 degrees for patients with greater posterior curve

Question 11

Where does the CR enter for AP axial sacrum?

Answer 11

MSP 2” superior to pubic symphysis

Question 12

What angulation is used for AP axial coccyx?

Answer 12

Supine (AP)
-10 degrees caudad

Prone (PA)
-10 degrees cephalad

Question 13

Where does the CR enter for a AP axial coccyx?

Answer 13

2”superior to pubic symphysis

*for PA, enters MSP at coccyx

Question 14

T/F
Collimation for AP coccyx should be as small as possible to increase visibility

Answer 14

True

Question 15

-recumbent lateral
-hips and knees flexed
-interiliac plane perpendicular to IR
-shoulders and pelvis in true lateral
-sacrum centered to IR

Answer 15

Lateral sacrum

Question 16

Where does the CR enter for a lateral sacrum?

Answer 16

3.5” posterior to ASIS

*lead behind patient to absorb scatter

Question 17

Where does the CR enter for a lateral coccyx?

Answer 17

3.5” posterior and 2” inferior to ASIS