Standard Operating Procedure: Diagnostic X-Ray Imaging

This Standard Operating Procedure (SOP) outlines the mandatory protocols for performing diagnostic X-ray imaging. The objective of this procedure is to ensure high-quality diagnostic images while strictly adhering to the ALARA (As Low As Reasonably Achievable) principle to minimize radiation exposure to patients and staff. All personnel operating X-ray equipment must hold current certification and follow institutional safety guidelines.

Phase 1: Pre-Examination Preparation

• Verify the physician's order for the correct examination type, anatomy, and clinical indication.
• Confirm patient identity using at least two unique identifiers (e.g., full name and date of birth).
• Assess the patient for pregnancy status (if applicable) and document responses according to facility policy.
• Review the patient’s medical history for relevant implants, hardware, or prior surgeries that may impact imaging.
• Remove all radiopaque objects (jewelry, piercings, bras with underwires, etc.) from the area of interest and provide a hospital gown if necessary.

Phase 2: Equipment Setup and Calibration

• Power on the X-ray console and allow the system to perform internal self-tests/calibration.
• Select the correct exposure parameters (kVp, mAs) based on the patient's habitus and the specific body part.
• Ensure the X-ray tube and detector (or bucky tray) are properly aligned and centered.
• Verify the Source-to-Image Distance (SID) is set according to department protocol (standardly 40 or 72 inches).
• Check that the appropriate grid is in place if the body part thickness exceeds 10–12 cm.

Phase 3: Patient Positioning and Radiation Safety

• Position the patient accurately, ensuring the anatomy of interest is centered to the image receptor.
• Utilize immobilization devices (sponges, sandbags) if the patient is unable to hold still.
• Apply gonadal shielding if it does not interfere with the primary diagnostic information.
• Collimate the X-ray beam to the smallest field size necessary to include the required anatomy.
• Ensure all staff and the patient (if applicable) are positioned behind the leaded control glass or wearing appropriate lead shielding (aprons, thyroid collars).

Phase 4: Exposure and Quality Assurance

• Give the patient clear, concise breathing instructions (e.g., "Take a breath in, blow it out, hold it still").
• Initiate the exposure only after verifying no unauthorized personnel are in the room.
• Observe the patient during exposure to ensure no motion occurs.
• Review the image immediately on the monitor for proper positioning, density, contrast, and lack of motion artifacts.
• Verify the Exposure Index (EI) is within the manufacturer's target range to ensure optimal image quality without overexposure.

Phase 5: Post-Examination Protocols

• Assist the patient off the table and provide instructions regarding follow-up care.
• Clean and disinfect all contact surfaces (tabletop, detector, sponges) using hospital-approved germicidal wipes.
• Ensure the patient's images have been successfully transmitted to the Picture Archiving and Communication System (PACS).
• Report any equipment malfunctions to the lead technologist or biomedical engineering department immediately.

Pro Tips & Pitfalls

• Pro Tip: Always utilize the collimator light to visualize the field before exposing; excessive radiation exposure often stems from over-collimation.
• Pro Tip: If an image is suboptimal, analyze the EI value before choosing to repeat the exposure. A slight adjustment in post-processing is often better than subjecting the patient to a second dose of radiation.
• Pitfall: "The Repeat Trap." Never repeat an image without correcting the underlying cause (e.g., re-instructing the patient on breathing or adjusting the patient's position) to prevent a second failed attempt.
• Pitfall: Failure to check pregnancy status. Always document a "Time-Out" or confirmation process for patients of childbearing age to prevent accidental fetal exposure.

Frequently Asked Questions

Q: What should I do if the Exposure Index (EI) is significantly outside the recommended range? A: Do not delete the image. Determine if the variance was due to patient habitus or a technical error. If the diagnostic quality is compromised, repeat the image after correcting the technique. Document the reason for the repeat in the Radiology Information System (RIS).

Q: Is it ever acceptable to bypass the gowning requirement for metallic objects? A: Only if the object is permanent hardware (e.g., surgical implants) or if the patient is in critical/unstable condition where movement would exacerbate an injury. In these cases, note the presence of the metal in the technologist's comments.

Q: How often should the lead shielding be inspected? A: All lead aprons, thyroid shields, and gloves must be inspected for cracks or tears via fluoroscopy or visual inspection every 6 to 12 months, and this inspection must be documented in the facility safety log.