title: Ultra-low iodine concentrations iso-attenuating with diagnostic 0.5M gadolinium in endovascular procedures to minimize the risk of contrast nephropathy: A phantom study.
abstract: OBJECTIVE
  To establish the concentrations of iodine contrast media (I-CM) iso-attenuating with 0.5M gadolinium contrast media (Gd-CM), regarded diagnostic in catheter angiography and vascular interventions in azotemic patients, at various X-ray tube potentials with correlation to skin radiation dose.
  
  
  METHODS
  20-mL syringes filled with 30, 40, 50, 70 and 90 mgI/mL, 0.5M Gd-CM and air were placed in a water-equivalent phantom and exposed at about 50, 60, 70, 80 and 90 kV in an X-ray angiographic system. Relative contrast between the contrast materials and the background phantom material was measured on a PACS workstation. Radiation entrance dose, measured with a dose meter and estimated from the dose-area-product (DAP), was adjusted for radiation backscatter to simulate absorbed skin dose.
  
  
  RESULTS
  The iodine concentrations 30, 40, 50, 70 and 90 mg/mL resulted in the same relative contrast as 0.5M gadolinium at 53, 57, 62, 71 and 85 kVp, respectively. Air had lower relative contrast than all iodine concentrations at all kVp-settings except for 30 mgI/mL above 84 kVp. The measured skin radiation dose was less than 1 mGy per exposure at all kVp-settings, and around 25-30% lower than the dose estimations derived from the angiographic system's in-built DAP meter.
  
  
  CONCLUSIONS
  Low-kilovoltage X-ray technique and ultra-low concentrations of I-CM iso-attenuating with 0.5M Gd-CM may be utilizable in peripheral arteriography and endovascular interventions, to minimize the total CM-dose to avoid CIN in azotemic patients.
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Section of Radiology, Uppsala University Hospital, SE-751 85 Uppsala, Sweden. Electronic address: jakob.swanberg@radiol.uu.se.
authors.forename: Jakob
authors.initials: J
authors.lastname: Swanberg
authors.affiliation: Department of Medical Physics, Uppsala University Hospital, SE-751 85 Uppsala, Sweden. Electronic address: per-erik.aslund@akademiska.se.
authors.forename: Per-Erik J
authors.initials: PE
authors.lastname: Åslund
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Section of Radiology, Uppsala University Hospital, SE-751 85 Uppsala, Sweden.
authors.forename: Rickard S
authors.initials: RS
authors.lastname: Nyman
authors.affiliation: Institution of Clinical Sciences, Lund University, SE-221 00 Lund, Sweden. Electronic address: ulf.nyman@bredband.net.
authors.forename: Ulf R O
authors.initials: UR
authors.lastname: Nyman
mesh_terms: D000792:Angiography / Q000379:methods; D003287:Contrast Media / Q000009:adverse effects*; D057510:Endovascular Procedures / Q000379:methods; D005260:Female; D005471:Fluoroscopy; D005682:Gadolinium / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D007455:Iodine / Q000008:administration & dosage; D007674:Kidney Diseases / Q000139:chemically induced / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D007455:Iodine; D005682:Gadolinium
keywords: Angiography; Contrast media; Contrast nephropathy; Renal failure