Monte Carlo simulations for assessment of organ radiation doses and cancer risk in patients undergoing abdominal stent-graft implantation.
OBJECTIVE
The aim of this work was to assess absorbed radiation doses in selected organs and to estimate cancer and mortality risks in patients undergoing abdominal stent-graft implantation, as a function of age, gender, and anatomical parameters of patients' aneurysms and arteries.


METHODS
297 patients (266 males and 31 females) underwent endovascular aortic aneurysm repair (EVAR) with abdominal stent-graft implantation. Kerma-area products Gy-cm(2) for all implanted patients were collected retrospectively. Entrance surface air kerma (ESAK), doses absorbed by selected organs, and cancer/mortality risks were estimated using Monte Carlo simulation methods (CALDose_X software).


RESULTS
The highest radiation doses were deposited in the skin, gallbladder wall, and colon wall. The highest average cancer risk was found for the youngest group of patients (<60 years old; 1:275) and the lowest for the oldest (>70 years old, 1:735). The radiation-induced risk of cancer mortality (mortality risk) was about 40% lower than radiation-induced cancer occurrence risk. Aneurysm neck angulations >45° had a significant impact on ESAK, as well as increasing cancer and mortality risks.


CONCLUSIONS
The main factors increasing cancer risk are young age and aneurysm neck angulations >45°, which determines the difficulty of proper stent-graft placement. However, the radiation risk associated with the stent-graft implantation procedure is relatively low, and EVAR should not be avoided.
Adam Mickiewicz University, Faculty of Physics, Department of Biomedical Physics, Poznan, Poland. Electronic address: blasaku@gmail.com.
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Blaszak
Department of General and Interventional Radiology, University of Medical Sciences, Poznan, Poland; Department of Neuroradiology, University of Medical Sciences, Poznan, Poland.
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Juszkat
D000328:Adult; D000367:Age Factors; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery*; D001027:Aortography / Q000009:adverse effects*; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D003198:Computer Simulation; D057510:Endovascular Procedures / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000401:mortality; D011044:Poland / Q000453:epidemiology; D011829:Radiation Dosage; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
Aneurysm; Endovascular aortic aneurysm repair (EVAR); Organ dose assessment; Radiation risk; Stent-graft implantation