Kerma-Area Product, Entrance Surface Dose and Effective Dose in Abdominal Endovascular Aneurysm Repair

Abstract

This study aims to evaluate patient radiation dose during fluoroscopically guided endovascular aneurysm repair (EVAR) procedures. Fluoroscopy time (FT) and kerma-area product (KAP) were recorded from 87 patients that underwent EVAR procedures with a mobile C-arm fluoroscopy system. Effective dose (ED) and organs’ doses were calculated utilising appropriate conversion coefficients based on the recorded KAP values. Entrance surface dose (ESD) was calculated based on KAP values and technical parameters. The mean FT was 22.7 min (range 6.4–76.8 min), resulting in a mean KAP of 36.6 Gy cm2 (range 2.0–167.8 Gy cm2), a mean ED of 6.2 mSv (range 0.3–28.5 mSv) and a mean ESD of 458 mGy (range 26–2098 mGy). The corresponding median values were 17.4 min, 25.6 Gy cm2, 4.4 mSv and 320 mGy. The threshold of 2 Gy for skin erythema was exceeded in two procedures for a focus-to-skin distance (FSD) of 40 cm and six procedures when an FSD of 30 cm was considered. The highest doses absorbed by the adrenals, kidneys, spleen and pancreas and ranged between 3.7 and 313.3 mGy (average 66.8 mGy), 3.3 and 285.1 mGy (average 60.8 mGy), 1.3 and 111.1 mGy (average 23.7 mGy), 1.1 and 92.1 mGy (average 19.6 mGy), respectively. A wide range of patient doses was reported in the literature. The radiation dose received by the patients was comparative or lower than most of the previously reported values. However, higher doses can be revealed due to the X-ray system’s non-optimum use and extended FTs, mainly affected by complex clinical conditions, patients’ body habitus and vascular surgeon experience. The large variation of patient doses highlights the potential to optimise the EVAR procedure by considering the balance between the radiation dose and the required image quality. Additional studies need to be conducted in increasing the vascular surgeons’ awareness regarding patient dose and radiation protection issues during EVAR procedures.

Factors Influencing Fluoroscopy Time in Endovascular Treatment of Abdominal Aneurysms: A Retrospective Study

“…A large variation was observed in the median and 75th percentile FT values compared with those published in previous studies ( 8 ) . This variation is mainly because of the differences in patients’ characteristics, complexity of clinical conditions and the type of fluoroscopic equipment used.…”

“…Fluoroscopy time (FT) is a patient dose surrogate commonly used to establish guidance and action levels ( 7 ) . The mean FT values published in previous studies range from 8.3 to 30.4 min ( 8 , 9 ) , whereas the mean procedure duration is about 2 h ( 10 , 11 ) . This variation in FT reflects the necessity for optimising these procedures since prolonged radiation exposures may result in patient deterministic or stochastic effects ( 12 ) .…”

“…No differences in FT values were found among the vascular surgeons, thus we considered all the procedures as one sample for the analysis. The EVAR technique has been previously described by the authors ( 8 ) .…”

Current Clinical Knowledge on GORE EXCLUDER Conformable Abdominal Aortic Aneurysm Repair Endoprosthesis: A Case Series and Literature Review

“…Dosimetric records must be kept and reported because high absorbed doses are related to increased radiation-induced cancer risk or deterministic effects such as skin erythema and fertility impairment. Detailed information on the detrimental effects of ionizing radiation during EVAR has been reported previously [ 5 ]. A pilot study of 32 patients treated with the predecessor of CEXC, the C3 Excluder repositionable device, was recently conducted.…”

“…Hostile neck anatomy (HNA) is a major determinant of proximal seal failure. An aortic neck is defined as hostile if it meets any one of the following criteria: (1) dilatation greater than or equal to 2 mm within 1 cm below the renals (reverse www.vsijournal.org taper); (2) angulation ≥60° within 3 cm below the renal arteries; (3) length ≤10 mm; (4) thrombus ≥50% of the circumference; and (5) focal bulge ≥3 mm within the first 1.5 cm below the most caudal renal artery [1]. There are also reports defining proximal necks with lengths of ≤15 mm as HNA because most commercially available endografts require a neck length of at least 15 mm [2,3].…”