Procedures
Core concepts
Procedures questions test projection selection, landmarks, and adaptation. Know the routines: chest PA and lateral (upright, 72-inch SID, full inspiration, apices through costophrenic angles); abdomen supine, upright, or decubitus (upright includes diaphragm to symphysis pubis); extremities with AP, oblique, and lateral views, including both joints when the long bone is the study; spine with appropriate SID and obliques; skull and sinus series; GI and GU contrast studies; and mobile or fluoroscopic examinations.
Positioning principles: place the part closest to the receptor, center the part to the receptor, align the beam perpendicular, rotate the patient precisely, and collimate to the anatomy. Breathing instructions matter: full inspiration for chest, suspended expiration for abdomen or when motion must be stopped.
Contrast exams require allergy screening, consent by the physician, bowel preparation per protocol, and knowledge of barium versus water-soluble iodinated media. Fluoroscopy adds dynamic evaluation and higher occupational dose - wear a lead apron, use pulsed or low-dose modes, and collimate tightly.
Adapt to the patient: trauma (do not move suspected fractures; use cross-table laterals), pediatrics (short exposure times, immobilization, careful shielding), and geriatrics (skin fragility, hearing loss, positioning aids). Document any deviation from the routine.
Traps
- Confusing AP and PA chest - PA reduces heart magnification and breast/thyroid dose.
- Ordering a decubitus view without a horizontal beam.
- Removing splints or dressings without an order.
- Omitting the second joint on a long-bone image.
- Insisting on an upright abdomen when the patient cannot stand - use a decubitus instead.
Rule of thumb
Center, collimate, then confirm: part–receptor alignment, perpendicular beam, and all required anatomy in the field before exposing.
Example: For a suspected hip fracture, obtain an AP hip/pelvis and a cross-table (dorsal decubitus) lateral rather than rolling the patient.