(Tuesday, 7/31/2018) 1:45 PM - 3:45 PM
Room: Room 207
Purpose: Development of a framework to compute and apply dose conversion coefficients to the most common pediatric diagnostic fluoroscopy studies.
Methods: This study focused on providing organ doses for the six most frequent procedures in the diagnostic fluoroscopy suite: upper gastrointestinal (UGI) series, UGI with small bowel follow through, lower gastrointestinal (LGI) series, voiding cystourethrogram (VCUG), rehab swallows (RS), and gastrostomy tube (G-tube) placement. Lack of machine produced radiation dose structured reports led to the development of procedural outlines, assembled through physician interviews and abstracted x-ray film data. Outlines included common x-ray fields-of-view, length of exposures, and field-of-view specific contrast agent anatomical location. Outlines were coupled with the 162 UF/NCI library pediatric computational phantoms to run Monte Carlo radiation transport. The transport model included characterization of contrast agents and machine parameters: half-value layer, geometry, and exit plane dose (for scaling purposes of the simulation output data).
Results: Absorbed doses for 28 organs, including active and shallow bone marrow, were assigned for all 162 pediatric phantoms across the six reference procedures. In addition, procedural organ doses are provided normalized to procedural dose indicators; doses are then broken into their component x-ray fields (fluoroscopic and spot films). This study is effectively producing dose conversion coefficients for common diagnostic fluoroscopy studies, to move from beam-on time, kerma area product (KAP), or reference point dose to organ dose. Organ doses are reported – per procedure and per procedure field- for each of the 85 pediatric males and 73 pediatric females of the UF/NCI hybrid phantom library, thus taking into account variations in patient body morphometry.
Conclusion: The development of this diagnostic fluoroscopy dose conversion coefficient database provides a methodology to estimate pediatric patient organ doses on a modality that has not previously provided such information. The applications of this database framework are extensive, ranging from contributions to historical epidemiology studies to impacting current hospital practice.
Authors:
Emily L Marshall, Dhanashree Rajderkar, Justin Brown, Elliott Stepusin, David Borrego, Wesley E Bolch
Keywords
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Taxonomy
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