81 - CT Fluoroscopy-Guided Percutaneous Procedures: What is the actual physician radiation dose vs. C-arm fluoroscopic procedures?

 Percutaneous CT Fluoroscopy (CTF) guided procedures have been shown to decrease complications and procedural time vs. conventional (out-of-room) CT guidance. However, many physicians forgo the use of in-room CTF due to concerns about operator radiation exposure. The purpose of this study is to determine the actual physician radiation dose during typical CTF procedures relative to common interventional C-arm fluoroscopic procedures. 

Materials and Methods:

A 32 cm diameter human scale phantom (Sun Nuclear Corporation) was positioned within the bore of a CT scanner (Aquilion One, Canon) in CTF mode. An ionization dose chamber (12 cm, 800 cc collection volume; Extradin A6, Standard Imaging) was stationed at a typical physician procedural location at lens height (158 cm). CTF scans were obtained (n=6 per parameter set) in “one-shot” (i.e. single rotation per tap) mode at typical lung and abdomen settings (120/135 kV, 20/50 mA, 0.5s rotation, 1.8 cm collimation) with and without the dose chamber shielded by a lead apron (0.5 mm lead equivalent). Mean number of taps per procedure was based on a survey of CTF procedures performed at a single academic center (n=2005, 2016-2020). Comparison data on physician exposure for interventional C-arm fluoroscopic procedures was obtained from the medical literature (Table).

Results:

Mean physician radiation dose (no lead) for typical CTF abdomen and lung procedures was 31.8 μGy (14.8-53.7 μGy). Mean radiation reduction using a lead apron ranged from 91.3% (135 kV) to 93.1% (120 kV) (p< 0.05 vs. unshielded). Mean dose for C-arm interventional procedures (n=222, literature based) was 105.6 μGy. Most common C-arm procedures included drainage (n=71), unspecified percutaneous procedures (n=48), angiography (n=40), vertebroplasty (n=29). Mean C-arm dose ranged from 2.0-7.1x vs. CTF depending on settings.   

Conclusion:

Typical physician radiation dose during chest and abdominal CTF procedures appears substantially lower than during C-arm fluoroscopic procedures, suggesting that forgoing CTF due to physician dose related concerns is unfounded.