Program Information
Lateral Head Shielding for Eye Lens Dose Reduction for Neuro-CBCT and Interventional Fluoroscopic Procedures
Z Xiong*, S Vijayan , C Guo , P Choudhary , S Rudin , D Bednarek , University at Buffalo, Buffalo, NY
Presentations
SU-E-201-5 (Sunday, July 30, 2017) 1:00 PM - 1:55 PM Room: 201
Purpose: The aim of this work is to investigate the effectiveness of placing small lead shields over the thin bone in the temple region of the skull to reduce the lens dose to patients in cone-beam computed tomography (CBCT) scans and interventional fluoroscopically-guided procedures of the head.
Methods: EGSnrc Monte Carlo software modeled the x-ray source of a C-Arm fluoroscope and was used to determine the lens dose for single x-ray projections, CBCT scans (different kVps and protocols), and a simulated fluoroscopically-guided procedure for the Zubal computational head phantom, which is based on a CT scan of an adult male whose eye lenses were individually segmented. The dose was calculated with and without small lead patches of different size and placement relative to the temple region. This study did not investigate the effect of the shields on the image, which will be done in a future work.
Results: For single lateral x-ray projections, a 0.2 mm thick lead patch reduced the dose to the left-eye lens by 50%-70% from 40° to 90° RAO and to the right-eye lens by 40%-50% from 70° to 90° RAO. For the Toshiba Infinix CBCT protocol, the reduction of lens dose is 16%, 36% and 42% for LCI-Fast, LCI-Middle and LCI-High protocols, respectively. For a simulated neuro-interventional procedure in a biplane machine, the eye lens-dose reduction was about 33% and most of the dose reduction was from the lateral C-arm. The effect of the size and position of the shield on lens-dose reduction was greater than its thickness.
Conclusion: This work shows that the use of small lateral lead shields placed over the temple region can effectively reduce the patient lens dose in imaging procedures of the head.
Funding Support, Disclosures, and Conflict of Interest: This research was supported in part by NIH Grant R01EB002873 and Toshiba Medical Systems Corp.
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