Sacrum
AP Axial IR Size: 10x12 LW SID: 40'' Page #'s: 1:430,174	Positioning:   • Pt Supine	CR Entrance & Angle:   • 2'' superior to pubic sym (2'' inf ASIS), (PA Axial 15° caudad)   • 15° cephalad Collimation:   • 9x11 Respiration:   • Suspend	Anatomy to IR:   • Eval Criteria:   • No foreshortening of sacrum with sacral curvature straightened   • Pubic bones not overlapping the sacrum   • NR of the sacrum, as indicated by symmetric alae & centered
Lateral IR Size: 10x12 LW SID: 40'' Page #'s: 1:432,176	Positioning:   • Pt TLP   • Knees superimposed (for stability)	CR Entrance & Angle:   • _|_ 3.5'' posterior to ASIS (For both Sacrum & Coccyx at same time 1'' inferior to ASIS)   • Collimation:   • 9x11 Respiration:   • Suspend	Eval Criteria:   • Use of tight collimation and a lead rubber absorber behind the sacrum   • Closely SI posterior margins of the ischia and ilia