Evaluation of the medical and occupational shielding in cerebral angiography using Monte Carlo simulations and virtual anthropomorphic phantoms

Author(s)

Santos, William S. ^[1] ; Neves, Lucio P. ^{[2, 1]} ; Perini, Ana P. ^{[2, 1]} ; Caldas, Linda V. E. ^[1] ; Maia, Ana F. ^{[2, 3]}

Affiliation

^[1] IPEN CNEN SP, Sao Paulo - Brazil

^[2] Univ Fed Uberlandia, Inst Fis, BR-38400902 Uberlandia, MG - Brazil

^[3] Univ Fed Sergipe, Dept Fis, BR-49100000 Sao Cristovao, SE - Brazil

• Document type: Journal article
• Source: Radiation Physics and Chemistry; v. 117, p. 83-87, DEC 2015.
• Web of Science Citations: 2

Abstract

Cerebral angiography exams may provide valuable diagnostic information for the patients with suspect of cerebral diseases, but it may also deliver high doses of radiation to the patients and medical staff. In order to evaluate the medical and occupational expositions from different irradiation conditions, Monte Carlo (MC) simulations were employed. Virtual anthropomorphic phantoms (MASH) were used to represent the patient and the physician inside a typical fluoroscopy room, also simulated in details, incorporated in the MCNPX 2.7.0 MC code. The evaluation was carried out by means of dose conversion coefficients (CCs) for equivalent (H) and effective (E) doses normalized by the air karma-area product (KAP). The CCs for the surface entrance dose of the patient (ESD) and equivalent dose for the eyes of the medical staff were determined, because CA exams present higher risks for those organs. The tube voltage was 80 kVp, and Al filters with thicknesses of 2.5 mm, 3.5 mm and 4.0 mm were positioned in the beams. Two projections were simulated: posterior-anterior (PA) and right-lateral (RLAT). In all situations there was an increase of the CC values with the increase of the Al filtration. The highest dose was obtained for a RLAT projection with a 4.0 mm Al filter. In this projection, the ESD/KAP and E/KAP values to patient were 11(14%) mGy/Gy cm(2) and 0.12 (0.1%) mSv/Gy cm(2), respectively. For the physician, the use of shield lead glass suspended and lead curtain attached to the surgical table resulted in a significant reduction of the CCs. The use of MC simulations proved to be a very important tool in radiation protection dosimetry, and specifically in this study several parameters could be evaluated, which would not be possible experimentally. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 13/15669-3 - Development and characterization of dosimetric nanomaterials and numerical dosimetry for dose assessment of patients during computed tomography and breast tomosynthesis exams
• Grantee: Lucio Pereira Neves
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/21741-9 - Determination of the doses in pediatric patients submitted to computed tomography exams and radiotherapy treatments
• Grantee: Ana Paula Perini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral