title: Radiation dose incurred in the exclusion of vascular filling in transforaminal epidural steroid injections: fluoroscopy, digital subtraction angiography, and CT/fluoroscopy.
abstract: OBJECTIVE
  This study seeks to measure the radiation dose incurred in the evaluation of vascular filling during transforaminal epidural steroid injections (TFESI) using conventional fluoroscopy (CF), digital subtraction angiography (DSA), and multislice, pulsed computed tomography fluoroscopy (CT/F).
  
  
  METHODS
  Three portable C-arms and a fixed multipurpose C-arm were evaluated. The radiation dose rate was measured using an anthropomorphic phantom during CF and DSA in anterior-posterior positions for cervical and lumbar TFESIs. Effective doses were calculated for 5-second exposures. The effective doses incurred in the cervical and lumbar spine during two CT/F exposures were calculated based on the reported volume CT dose index and dose length product.
  
  
  RESULTS
  DSA imaging increased the effective dose incurred over CF with portable C-arms (medium dose rate) by 2.5-4.3 fold for cervical TFESI and 2.3-4.2 fold for lumbar TFESI. The incremental dose incurred with DSA ranged from 4.0 to 7.7 μSv in the cervical region and from 22-38 μSv in the lumbar spine. CT/F increased the incurred dose 19-fold in the cervical region and 8.0-fold in the lumbar region (incremental doses 49 μSv and 140 μSv, respectively) relative to CF.
  
  
  CONCLUSIONS
  The use of DSA imaging to exclude vascular uptake during TFESI increases radiation dose over CF. CT/F incurs additional dose beyond most DSA. Minimizing radiation dose by limiting DSA and CT/F use to spine segments or clinical situations involving higher risk may be desirable. However, the incremental radiation doses incurred by DSA or CT/F are of such low magnitude that health risks cannot currently be estimated.
authors: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Timothy
authors: T
authors: Maus
authors: Beth A
authors: BA
authors: Schueler
authors: Shuai
authors: S
authors: Leng
authors: Dayne
authors: D
authors: Magnuson
authors: Dixon J
authors: DJ
authors: Magnuson
authors: Felix E
authors: FE
authors: Diehn
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D015901:Angiography, Digital Subtraction / Q000009:adverse effects*; D005471:Fluoroscopy / Q000009:adverse effects*; D006801:Humans; D007268:Injections, Epidural / Q000009:adverse effects*; D064847:Multimodal Imaging / Q000009:adverse effects; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000009:adverse effects*
chemical_list: D000305:Adrenal Cortex Hormones
keywords: Epidural (Injection Space); Fluoroscopy; Radiculopathy; Safety; Steroids