Overview
Definition:
Intraoperative fluoroscopy is a real-time X-ray imaging technique used during surgical procedures to visualize anatomical structures, guide instrumentation, and confirm placement of implants or devices
Its effective use requires strict adherence to safety protocols to minimize radiation exposure to the surgical team and patient.
Epidemiology:
Fluoroscopy is widely used in various surgical specialties including orthopedic, cardiothoracic, neurosurgery, urology, and gastrointestinal surgery
The cumulative radiation dose received by surgeons can be significant over their careers, necessitating robust safety measures.
Clinical Significance:
Proper application of intraoperative fluoroscopy is crucial for successful surgical outcomes, enabling precise interventions
However, inadequate safety practices lead to increased risk of deterministic effects (e.g., skin burns) and stochastic effects (e.g., cancer) for healthcare professionals, highlighting the need for comprehensive training and adherence to radiation safety principles.
Radiation Physics Principles
Radiation Properties:
X-rays are ionizing radiation, capable of causing cellular damage
The intensity of X-ray beams decreases with distance from the source (inverse square law)
Lead shielding is effective in attenuating X-rays.
Dose Units:
Radiation dose is measured in Gray (Gy) or Sievert (Sv)
Effective dose accounts for the biological harm
Occupational dose limits are set by regulatory bodies to protect workers.
Factors Affecting Dose:
Key factors influencing radiation dose include beam energy (kVp), beam current (mA), exposure time, distance from the source, filtration, collimation, and patient positioning
Higher kVp generally leads to lower patient dose but can increase scattered radiation
Higher mA and longer exposure times directly increase dose.
Safety Protocols For Surgeons
Alara Principle:
As Low As Reasonably Achievable (ALARA) is the fundamental principle
Minimize time, maximize distance, and use shielding whenever possible.
Personal Protective Equipment:
Mandatory use of lead aprons (minimum 0.5 mm lead equivalent), thyroid shields, and leaded glasses
Lead gloves may be necessary for certain procedures
Ensure proper fit and condition of PPE.
Positioning And Distance:
Stand as far as possible from the X-ray source
The inverse square law states that doubling the distance reduces exposure by a factor of four
Position yourself at the side of the X-ray tube, away from the primary beam exit port.
Collimation And Filtration:
Use collimation to restrict the X-ray beam to the area of interest, reducing scatter radiation
Ensure the fluoroscope has adequate filtration to remove low-energy photons that contribute to dose without improving image quality.
Time Management:
Minimize fluoroscopy time by planning the procedure effectively
Use pulsed fluoroscopy when available instead of continuous mode, and use the lowest frame rate that provides adequate visualization.
Equipment And Shielding
C Arm Operation:
Understand the specific controls and features of the C-arm unit
Familiarize yourself with its limitations and potential radiation hotspots
Regularly check equipment for faults.
Lead Drapes And Bucky Grids:
Utilize lead drapes attached to the image intensifier or flat-panel detector to block scatter radiation
Bucky grids can reduce scatter but may increase patient dose slightly due to beam attenuation
their use should be judicious.
Lead Screens And Partitions:
Position portable lead screens between the radiation source and the surgical team to absorb scattered radiation
Surgical rooms should have appropriate lead-lined walls and doors where necessary.
Table Selection:
Use radiolucent operating tables to minimize beam attenuation
Avoid placing dense materials like metal instruments directly in the primary beam path unless they are the target of imaging.
Patient Radiation Safety
Informed Consent:
Discuss the risks and benefits of fluoroscopy with the patient, including potential radiation exposure, as part of the informed consent process.
Dose Monitoring:
Keep track of fluoroscopy time and dose area product (DAP) displayed by the fluoroscope
Document these values in the patient's record.
Minimizing Patient Dose:
Optimize imaging parameters for the lowest possible dose while maintaining diagnostic quality
Avoid unnecessary imaging
Use magnification judiciously as it increases dose
Consider alternative imaging modalities if fluoroscopy is not essential.
Common Scenarios And Challenges
Orthopedic Surgery:
High use of fluoroscopy for fracture reduction, implant placement
Challenges include long procedure times and significant scatter from bone
Strict adherence to ALARA and shielding is vital.
Cardiovascular Interventions:
Complex procedures requiring prolonged fluoroscopy
Risk of scatter radiation to the entire team
Importance of shielding, distance, and optimized imaging protocols.
Neurosurgery:
Used for spine surgery and instrumentation
Requires precise imaging in confined spaces, demanding careful positioning to maximize safety.
Emergency Situations:
In critical, time-sensitive situations, balancing the need for rapid imaging with radiation safety can be challenging
Pre-planning and clear communication among the team are key to minimizing risk.
Key Points
Exam Focus:
DNB/NEET SS exams often test understanding of radiation physics, ALARA principle, PPE, and specific safety measures for common surgical procedures
Knowledge of occupational dose limits and risks of cumulative exposure is important.
Clinical Pearls:
Always think before you push the pedal
Pre-plan your shots
Use the lowest kVp possible for adequate contrast, which generally reduces scatter
Educate junior residents and nurses on safety protocols.
Common Mistakes:
Forgetting to wear leaded eyewear
Standing too close to the C-arm
Unnecessary continuous fluoroscopy
Not collimating the beam
Inadequate shielding for team members
Over-reliance on magnification.