title: Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room. An Instant Patient Risk Chart for Daily Practice.
abstract: To determine which patient and C-arm characteristics are the strongest predictors of intraoperative patient radiation dose rates (DRs) during endovascular aneurysm repair (EVAR) procedures and create a patient risk chart.
  
  
  
  A retrospective analysis was performed of 74 EVAR procedures, including 16,889 X-ray runs using fixed C-arm imaging equipment. Four multivariate log-linear mixed models (with patient as a random effect) were constructed. Mean air kerma DR (DRAK, mGy/s) and the mean dose area product DR (DRDAP, mGycm2/s) were the outcome variables utilized for fluoroscopy as differentiated from digital subtraction angiography (DSA). These models were used to predict the maximum radiation duration allowed before a 2-Gy skin threshold (for DRAK) or a 500-Gycm2threshold (for DRDAP) was reached.
  
  
  
  The strongest predictor of DRAKand DRDAPfor fluoroscopy imaging was the radiation protocol, with an increase of 200% when changing from "low" to "medium" and 410% from "low" to "normal." The strongest predictors of DRAKand DRDAPfor DSA were C-arm angulation, with an increase of 47% per 30° of angulation, and body mass index (BMI), with an increase of 58% for every 5-point increase in BMI. Based on these models, a patient with a BMI of 30 kg/m2, combined with 45° of rotation and a field size of 800 cm2in the medium fluoroscopy protocol has a predicted DRAKof 0.39 mGy/s (or 85.5 minutes until the 2-Gy skin threshold is reached). While using comparable settings but switching the acquisition to a DSA with a "2 frames per second" protocol, the predicted DRAKwill be 6.6 mGy/s (or 5.0 minutes until the 2-Gy threshold is reached).
  
  
  
  X-ray radiation DRs are constantly fluctuating during and between patients based on BMI, the protocols, C-arm position, and the image acquisitions that are used. An instant patient risk chart visualizes these radiation dose fluctuations and provides an overview of the expected duration of X-ray radiation, which can be used to predict when follow-up dose thresholds are reached during abdominal endovascular procedures.
authors.affiliation: 1 Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.
authors.forename: Quirina M
authors.initials: QM
authors.lastname: de Ruiter
authors.affiliation: 2 ICIN-Netherlands Heart Institute, Utrecht, the Netherlands.|3 Laboratory of Experimental Cardiology, University Medical Center Utrecht, the Netherlands.
authors.forename: Crystel M
authors.initials: CM
authors.lastname: Gijsberts
authors.affiliation: 1 Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.
authors.forename: Constantijn E
authors.initials: CE
authors.lastname: Hazenberg
authors.affiliation: 1 Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.
authors.forename: Frans L
authors.initials: FL
authors.lastname: Moll
authors.affiliation: 1 Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.
authors.forename: Joost A
authors.initials: JA
authors.lastname: van Herwaarden
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation; D015992:Body Mass Index; D003661:Decision Support Techniques; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D061214:Patient Safety; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000009:adverse effects; D015641:Radiography, Interventional / Q000009:adverse effects / Q000295:instrumentation; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors
keywords: C-arm image intensifier; X-ray; abdominal aortic aneurysm; air kerma; digital subtraction angiography; dose area product; dose reduction; endovascular aneurysm repair; fluoroscopy; imaging technology; radiation dose; risk assessment