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SU‐E‐J‐43: Autotuning Imaging Parameters in X‐Ray Fluoroscopic Tracking for Dose Savings
Author(s) -
Siddique S,
Fiume E,
Jaffray D
Publication year - 2012
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4734878
Subject(s) - fluoroscopy , detector , tracking (education) , flat panel detector , tube (container) , filter (signal processing) , pixel , metric (unit) , medical imaging , nuclear medicine , computer science , physics , optics , medical physics , materials science , artificial intelligence , computer vision , medicine , engineering , psychology , pedagogy , operations management , composite material , nuclear physics
Purpose: In fluoroscopy‐guided clinical procedures that involve tracking objects over long treatment times, there is a need for reducing the amount of imaging dose delivered to the patient and the operating staff. In this study, we introduce a feedback metric to minimize tube current while maintaining a targeting precision threshold.Method and Materials: An acrylic sphere (1.6mm in diameter) was imaged at tube currents ranging from 0.5 mA to 0.9mA (1s) at a fixed energy of 50kVp. The images were acquired on a Varian Paxscan 4030A (2048×1536 pixels, 1100 mm source‐to‐axis distance, 1570 mm source‐to‐detector distance). A state feedback metric (tr(C)) based on the current object position was computed and plotted as afunction of the tube current. Next, the sphere was tracked using a particle filter with a bowtie filter (4.3–764mm thickness, Al) in the background. The tr(C) was used a by a PID controller to modulate the tube current in order to maintain a specified precision as the sphere traversed regions of varying thickness corresponding to the bowtie filter. Result: Comparison of thefeedback framework with a similar system employing fixed exposurereveals a dose savings of up to 43% when using an operating uncertainty of 194 mm 2 . Conclusion: This work presents a relation between tr(C) and thetube current which can be leveraged to reduce imaging dose to patients and staff.