title: Effect of Body Habitus on Radiation Dose During CT Fluoroscopy-Guided Spine Injections.
abstract: This study investigated the degree to which body habitus influences radiation dose during CT fluoroscopy (CTF)-guided lumbar epidural steroid injections (ESI). An anthropomorphic phantom containing metal oxide semiconductor field effect transistor (MOSFET) detectors was scanned at two transverse levels to simulate upper and lower lumbar CTF-guided ESI. Circumferential layers of adipose-equivalent material were sequentially added to model patients of three sizes: small (cross-sectional dimensions 25×30 cm), average (34×39 cm), and oversize (43×48 cm). Point dose rates to skin and internal organs within the CTF beam were measured. Scattered point dose rates 5 cm from the radiation beam were also measured. Direct point dose rates to the internal organs ranged from 0.05-0.11 mGy/10mAs in the oversized phantom, and from 0.18-0.43 mGy/10mAs in the small phantom. Skin direct point dose rates ranged from 0.69-0.71 mGy/10mAs in the oversized phantom and 0.88-0.94 mGy/10mAs in the small phantom. This represents a 180-310% increase in organ point dose rates and 24-36% increase in skin point dose rates in the small habitus compared with the oversize habitus. Scatter point dose rates increased by 83-117% for the small compared to the oversize phantom. Decreasing body habitus results in substantial increases in direct organ and skin point doses as well as scattered dose during simulated CTF-guided procedures. Failure to account for individual variations in body habitus will result in inaccurate dose estimation and inappropriate choice of tube current in CTF-guided procedures.
authors.affiliation: Department of Radiology, Duke University Medical Center; Durham, NC, USA - peter.kranz@duke.edu.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Viola
authors.affiliation: Department of Radiology, Duke University Medical Center; Durham, NC, USA.
authors.forename: Giao B
authors.initials: GB
authors.lastname: Nguyen
authors.affiliation: Department of Radiology, Duke University Medical Center; Durham, NC, USA.
authors.forename: Terry T
authors.initials: TT
authors.lastname: Yoshizumi
authors.affiliation: Department of Biostatistics and Bioinformatics, Duke University Medical Center; Durham, NC, USA.
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Stinnett
authors.affiliation: Department of Radiology, Duke University Medical Center; Durham, NC, USA.
authors.forename: Jenny K
authors.initials: JK
authors.lastname: Hoang
authors.affiliation: Department of Radiology, Duke University Medical Center; Durham, NC, USA.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kranz
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use; D005471:Fluoroscopy / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007268:Injections, Epidural / Q000379:methods*; D008161:Lumbosacral Region; D008838:Microcomputers; D011829:Radiation Dosage; D015641:Radiography, Interventional; D012867:Skin / Q000528:radiation effects; D013131:Spine / Q000000981:diagnostic imaging; D013256:Steroids / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; D013256:Steroids
keywords: CT fluoroscopy; body habitus; epidural injections; radiation dosimetry; spine therapy