What are the best ways for a neurointerventionalist to minimize radiation exposure during biplane neurointerventional cases?

Radiation Protection Strategies for Neurointerventionalists in Biplane Cases

Neurointerventionalists should prioritize direct, independent operation of the biplane angiographic system (BAS) rather than relying on radiographer-assisted control, as this single intervention can reduce radiation exposure by up to 38% while maintaining procedural efficacy. 1

Core ALARA Principles for Biplane Neurointervention

The fundamental approach to radiation safety follows the ALARA (As Low As Reasonably Achievable) principle, which recognizes that there is no absolutely safe dose of ionizing radiation and that incremental exposures have cumulative effects. 2 Most practices that minimize patient dose also protect the operator and clinical personnel. 2

Critical Distance and Positioning Strategies

• Maximize distance between the X-ray tube and yourself while minimizing the distance between the patient and the image detector. 2
• Position the patient near the imaging system's isocenter to optimize geometry. 2
• In biplane systems, be particularly aware that both planes contribute to scatter radiation—position yourself strategically relative to both X-ray sources. 3
• Raising the patient away from the X-ray tube is one of the most effective dose reduction strategies. 2

Equipment Operation and Technical Optimization

Fluoroscopy Time Management

• Activate the fluoroscopic beam only when actively utilizing dynamic information—never irradiate unless your eyes are on the monitor. 2
• Use the last image hold feature extensively to study anatomic details without ongoing radiation exposure. 2
• Employ the slowest fluoroscopy pulse rate that produces satisfactory images (reducing pulse rate is highly effective for dose reduction). 2
• Use high-dose fluoroscopy mode only when enhanced image quality is absolutely necessary. 2

Acquisition and Imaging Parameters

• Minimize the number of digital subtraction angiography (DSA) runs to the minimum consistent with accurate diagnosis. 2
• Use the slowest acquisition frame rate adequate for diagnosis. 2
• Limit magnification to the least degree required for accurate interpretation—dose increases substantially with magnification in conventional image intensifiers. 2
• Modern flat-panel detector systems may have smaller dose increments with magnification but should still be minimized. 2

Collimation and Beam Management

• Use active collimation to limit the X-ray beam to the minimum area needed—wide-open collimators deliver unnecessary radiation to both patient and personnel. 2
• Employ tight collimation throughout the procedure. 2
• Use beam-hardening filters whenever feasible. 2

Biplane-Specific Considerations

Comparative Dose Profiles

• Biplane systems demonstrate significantly lower dose-area product (DAP) for interventional cases compared to monoplane systems, though diagnostic angiography shows no significant difference. 3
• For neurointerventions, biplane equipment can reduce patient radiation exposure while contributing to safer and more efficacious procedures. 3
• Typical DAP values for diagnostic cerebral angiography on modern biplane systems range from 43 (33-60) Gy×cm², with interventions at 66 (41-110) Gy×cm². 4

Projection Management

• Minimize non-essential oblique projections, as these increase dose substantially. 2
• During long procedures, vary the radiographic projection when clinically feasible to minimize dose to any particular skin entrance port. 2
• Coordinate both planes efficiently to avoid redundant imaging.

Operator Training and System Mastery

Direct System Operation

• Formal training to independently operate the BAS should be part of the core skillset for qualified neurointerventionalists. 1
• Working independently with the BAS allows mean dose reduction of up to 38% compared to radiographer-assisted operation (4,655 μGy·m² vs >7,000 μGy·m²). 1
• Understanding and utilizing the X-ray unit's dose-reduction features can substantially reduce dose. 2

Detector Dose Optimization

• Consider reducing baseline detector dose settings from factory defaults—studies show detector dose can be reduced from 3.6 to 1.2 μGy/frame without compromising diagnostic image quality. 5
• This simple adjustment can reduce reference air kerma and kerma area product by approximately 61%. 5
• Baseline factory settings may be unnecessarily high and should be reconsidered for neurointerventional protocols. 5

Additional Protective Measures

Grid and Current Management

• Remove the grid when appropriate to reduce dose. 2
• Reduce tube current when image quality permits. 2
• Minimize the image intensifier-patient distance. 2

Procedural Efficiency

• An experienced interventionalist should perform as primary operator when possible to reduce fluoroscopy times. 2
• Limit femoral angiography to essential views only. 2
• Record estimated dose delivered to the patient for quality monitoring. 2

Common Pitfalls to Avoid

• Do not rely solely on lead shielding for operator protection—while it may provide psychological reassurance, distance and time reduction are far more effective. 2
• Avoid the practice of continuous fluoroscopy during catheter manipulation—use intermittent pulsed imaging instead. 2
• Do not use maximum magnification by default—select magnification based on actual diagnostic need. 2
• Never assume factory settings are optimized—actively adjust parameters for each case. 5

Dose Monitoring and Thresholds

• Monitor fluoroscopy time and cumulative dose throughout the procedure. 2
• Be aware that procedures exceeding 50 minutes of fluoroscopy time or delivering >4 Gy to the interventional reference point warrant patient follow-up at 1 and 3 months for radiation injury. 2
• For obese patients or procedures using equipment >5 years old, reduce this threshold to 30 minutes. 2