What are the strategies to minimize radiation exposure to patients and OR personnel during procedures involving fluoroscopy or C-arm use?

Minimizing Radiation Exposure During C-arm Fluoroscopy

The most significant operational factor resulting in increased radiation dose to patients and OR personnel is elevating the image receptor (intensifier) away from the patient's body, which can increase radiation exposure by as much as 260% compared to optimal positioning. 1

Key Operational Factors Affecting Radiation Exposure

Image Receptor Positioning

• Maintaining minimal distance between the patient and image receptor is crucial - elevating the image intensifier creates an "air gap" that significantly increases radiation output 1
• If a procedure with optimal positioning required a 3 Gy skin dose, the same procedure with an elevated image intensifier would result in a 7.8 Gy dose 1
• The X-ray system should be positioned so that the distance from the patient to the image detector is minimized 2

X-ray Tube Positioning

• Maximize the distance between the X-ray tube and patient when possible 2
• Placing the X-ray tube too close to the patient's body greatly increases dose to the skin 1
• The best configuration to reduce radiation dose to the surgeon is positioning the fluoroscopic source below the operating table and the image collector above 3

Beam-on Time Management

• Minimize beam-on time for both fluoroscopy and acquisition 2
• The fluoroscopic beam should be on only when dynamic information is being actively utilized 2
• Never irradiate the patient unless the primary operator's eyes are on the monitor 2
• Use the "last image hold" feature to study anatomic details without ongoing radiation exposure 2

Beam Collimation

• Use optimal beam collimation to limit X-ray beam size to the minimum area needed 2
• Proper collimation reduces scattered radiation both within the patient and in the procedure room 1
• Fluoroscopy with collimator leaves wide open delivers unnecessary radiation to both patient and clinical personnel 2

Magnification Settings

• Use the least degree of image magnification required for accurate interpretation 2
• The dose increases substantially with increasing magnification - approximately 1.7 times higher in the 7-inch mode compared to the 9-inch mode 2
• For X-ray systems with conventional image intensifiers, dose generally increases substantially with increasing magnification 2

Dose Reduction Strategies

Equipment Features

• Use pulsed fluoroscopy instead of continuous fluoroscopy (reduces exposure by approximately 50%) 2
• Use the slowest fluoroscopy pulse rate and lowest dose rate that produces satisfactory images 2
• Use high-dose fluoroscopy only when enhanced image quality is absolutely necessary 2
• Employ beam-hardening filters when feasible 2
• Utilize additional copper filters, digital-only cine acquisition, and high-frequency generators 2

Procedural Techniques

• Vary the site of the radiation entrance port during lengthy procedures to minimize dose to any particular skin area 2
• For cross-table imaging, the surgeon should stand on the side with the image collector to minimize exposure to radiation scatter 3
• Standing farther away from the patient can exponentially reduce radiation exposure to personnel 3
• Use hands-off technique, taking fluoroscopic images only when hands are farthest from the radiographic field 3

Patient Factors

• Patient size significantly impacts radiation exposure - larger patients generate more scattered radiation 1, 4
• The threshold for radiation injury warning should be reduced to 30 minutes of fluoroscopy (versus 50 minutes) if the patient is obese 2

Protection for OR Personnel

• Lead gowns, thyroid shields, and lead glasses significantly reduce individual exposure to radiation 3
• The dominant hand typically receives the maximum radiation exposure during procedures 5
• Radiation scatter is mainly directed toward the fluoroscopy source - personnel should position themselves accordingly 3
• The highest radiation doses are recorded for personnel positioned immediately adjacent to the C-arm X-ray tube 4

ALARA Principle Implementation

• The ALARA (As Low As Reasonably Achievable) principle recognizes there is no known absolutely safe dose of ionizing radiation 2
• The smaller the dose, the less the risk of adverse effects 2
• Incremental radiation exposures have cumulative effects 2
• The practice of ALARA in an interventional suite requires careful attention to technical detail to reduce patient dose 6

By implementing these strategies, radiation exposure to both patients and OR personnel can be significantly reduced while maintaining adequate image quality for safe and effective procedures.