Standard Operating Procedure (SOP)

Cone Beam Computed Tomography (CBCT) - Veterinary Practice

1. PURPOSE

2. SCOPE

3. RESPONSIBILITIES

4. PREREQUISITES AND PREREQUISITES CHECKLIST

• Valid veterinary prescription / clinical indication documented
• Patient identity confirmed (species, name, weight, patient ID)
• Anaesthesia/sedation plan confirmed with supervising vet
• Relevant medical history reviewed (prior imaging, allergies, contraindications)
• Radiation dosimetry badge (TLD/OSL badge) worn by all staff
• PPE available: lead aprons, thyroid shields, lead gloves if needed

5. PERSONAL PROTECTIVE EQUIPMENT (PPE) REQUIREMENTS

1. All personnel in the scanning room during scout/positioning must wear a lead apron (min. 0.25-0.5 mm Pb equivalent) and thyroid collar.
2. Dosimetry badges must be worn at collar level (outside apron) at all times.
3. During X-ray emission, all staff must exit the room or stand behind the lead-lined barrier.
4. Line-of-sight anaesthesia monitoring must be maintained (visual/camera/monitoring equipment).
5. PPE must be inspected at least annually for cracks or leaks and replaced as needed.

6. MACHINE SETUP AND PRE-SCAN CHECKS

6.1 Daily Startup

1. Power on the CBCT unit per manufacturer instructions (e.g., NewTom 7G VET, VetCAT, Planmeca ProMax).
2. Allow the unit to complete its self-diagnostic warm-up cycle.
3. Log in to the imaging workstation and confirm software (NNT, CS 3D, or equivalent) is operational.
4. Verify detector calibration is current; run flat-field/dark-field calibration if prompted.
5. Check that the patient table/stretcher is clean and free of artefact-causing objects.
6. Confirm the room is clear of non-essential personnel.

6.2 Quality Control (QC)

• Perform daily QC scan using phantom (if available) per manufacturer protocol.
• Log all QC results in the Equipment QC Register.
• Report any image quality degradation, artefacts, or mechanical issues to the RSO immediately - do not use the machine until cleared.

7. PATIENT PREPARATION

1. Anaesthesia/Sedation: All veterinary CBCT scans require the patient to be under general anaesthesia or deep sedation to eliminate motion artefact.
   • Confirm anaesthesia induction is complete and airway is secured before positioning.
   • Attach monitoring equipment (pulse oximeter, capnograph, ECG).
2. Positioning: Select patient position based on anatomical region of interest:
   • Dental/maxillofacial: Dorsal recumbency (sternal) with head in gantry, mandible parallel to the detector plane.
   • Skull/ears: Lateral or dorsal recumbency per diagnostic need.
   • Body/limbs (for units with body CBCT capability): Position on stretcher according to manufacturer's anatomical reference guide.
   • Use radiolucent foam pads and positioning aids - no metallic objects near the scan field.
   • Remove all collars, leads, metallic devices, and dental metalwork if possible.
3. Field of View (FOV) Selection:
   • Use the smallest FOV that covers the area of interest to minimise radiation dose (ALARA principle).
   • For dental: typically 8x8 cm or 10x10 cm FOV.
   • For full skull: 17x17 cm or larger (machine-dependent).
   • Document selected FOV in patient record.
4. Scan Protocol Selection:
   • Select appropriate kVp and mA based on patient size and weight.
   • Use automatic exposure control (SafeBeam™ or equivalent) when available.
   • Choose Low Dose (ECO) protocol where diagnostic quality is still achieved.
   • Document all scan parameters (kVp, mA, FOV, scan time, exposure time).

8. SCANNING PROCEDURE

1. Position the patient and confirm gantry clearance - no part of the patient should touch the gantry during rotation.
2. Perform a scout (localiser) image to confirm correct positioning before full scan.
3. Ensure all personnel have exited the scan room before initiating X-ray emission.
4. Confirm the radiation warning light/buzzer is functioning outside the room.
5. Initiate the scan from the control console.
6. Monitor the patient via anaesthetic monitoring equipment (camera or window view) throughout the scan (scan time: typically 7-26 seconds).
7. On scan completion, re-enter the room promptly and attend to the patient.
8. Transfer image data to workstation and confirm image acquisition was successful before moving the patient.

9. POST-SCAN PROCEDURE

1. Recover the patient from anaesthesia per facility anaesthesia recovery SOP.
2. Label and save the DICOM dataset with correct patient ID, species, date, and referring vet details.
3. Create the 3D reconstruction using appropriate software (NNT viewer, OnDemand3D, Dolphin 3D, or equivalent).
4. Archive images per the facility's data management policy (minimum retention as per local regulations - typically 7 years).
5. Generate a diagnostic report or refer images to a board-certified veterinary radiologist/dentist as appropriate.

10. RADIATION SAFETY - ALARA PRINCIPLES

• Dosimetry badge results must be reviewed monthly by the RSO.
• Cumulative dose records must be maintained for all radiation workers.
• Pregnant staff must inform the RSO immediately and be temporarily reassigned from radiation duties.

11. INFECTION CONTROL

1. Clean and disinfect the patient table, head support, and all contact surfaces between patients with an appropriate veterinary disinfectant.
2. Use disposable covers on positioning aids where possible.
3. Follow standard handwashing/hand hygiene protocols before and after patient handling.

12. FAULT REPORTING AND EMERGENCY PROCEDURES

• If the machine malfunctions mid-scan, abort the scan via the emergency stop and attend to the patient first.
• Do not attempt repairs - contact the manufacturer's service engineer.
• Log all faults in the Equipment Fault Register with date, description, and action taken.
• If a radiation incident occurs (e.g., accidental beam exposure to staff), report immediately to the RSO and follow the facility's radiation incident reporting procedure.

13. DOCUMENTATION AND RECORDS

14. TRAINING REQUIREMENTS

• All operators must complete documented training on the specific CBCT unit before independent use.
• Annual radiation safety refresher training is mandatory for all staff working with ionising radiation.
• Training records must be retained and made available for regulatory inspection.

15. REFERENCES

• ACVR Radiation Safety Statement
• Health Canada Safety Code 28 - Radiation Protection in Veterinary Medicine
• NewTom 7G VET Operator Manual
• IDEXX Veterinary Radiation Safety Center
• Bannon K. Cone Beam Computed Tomography in Veterinary Dentistry. Today's Veterinary Practice, peer-reviewed article
• Local/national radiation protection regulations (adapt to your jurisdiction: AERB in India, HSE in UK, NRC in USA, ARPANSA in Australia)

Note: This SOP must be reviewed annually or whenever the equipment, software, or relevant regulations change. Adapt specific parameters (kVp, mA ranges, FOV sizes) to your machine model and manufacturer specifications. Consult your local radiation authority for licensing and regulatory compliance requirements specific to your country.