Note: The urinary bladder should be emptied before the procedure begins. Also patient may require to take a cleaning enema as ordered by the doctor to remove fecal material and gas in the colon.
- Image receptor size - 24 x 30 cm or 10 x 12 inches film used. Lengthwise
- Moving or stationary grid
- 75 to 80 kV range or 85 to 90 kV but mAs is reduced.
- mAs for 80 kV is 15 and 90 kV is 8.
Use of Shielding:
|AP Coccyx 10° Caudad|
- For male patient use of gonadal shielding.
- Ovarian shielding for females
- Use of shielding in females is not possible without obscuring the area being examined.
Patient and Part Positioning:
- Patient is in supine position, provide pillow for head support and legs are extended, with support under knees for patient comfort.
- Midsagital plane is align to table or grid.
- Ensure that the pelvis is not rotated.
Central Ray, Collimation and Respiration:
- Angulate centeral rat 10° caudad towards the feet, to enter 2 inches in the upper symphysis pubis.
- Image receptor is align to center ray.
- SID of 40 inches used.
- The four side of area of interest is well collimated.
- Suspend breathing on expiration.
Notes: Increase central angle to 15° caudad if the curvature of the anterior coccyx is greater. palpation or as evidence on the lateral.
This may also be done in prone position if necessary to patient condition, in 10° cephalad angle.
Center central ray to coccyx by localizing the greater trochanter.
Radiographic Criteria | X-ray of Coccyx:
- Coccyx free of self-superimposition and superimposition of symphysis pubis.
- Correct coccyx and central ray alignment demonstrate coccyx free of superimposition and projected superior to pubis.
- Coccygeal segments should appear open on radiograph, if not they may be fused, or an increase on central ray angulation. (the greater the curvature of the coccyx, the greater is the angulation needed).
- Coccyx should appear equal distant from lateral walls of the pelvic opening, this is an indication of correct positioning and no patient rotation.
Collimation, Central Ray and Exposure Factors:
- The coccyx should be in the middle of collimated field or in the radiograph.
- Optimal density and contrast demonstrate the coccyx.
- Sharp bony margins indication of no motion.