title: Can contrast media increase organ doses in CT examinations? A clinical study.
abstract: OBJECTIVE
  The purpose of this article is to quantify the CT radiation dose increment in five organs resulting from the administration of iodinated contrast medium.
  
  
  METHODS
  Forty consecutive patients who underwent both un-enhanced and contrast-enhanced thoracoabdominal CT were included in our retrospective study. The dose increase between CT before and after contrast agent administration was evaluated in the portal phase for the thyroid, liver, spleen, pancreas, and kidneys by applying a previously validated method.
  
  
  RESULTS
  An increase in radiation dose was noted in all organs studied. Average dose increments were 19% for liver, 71% for kidneys, 33% for spleen and pancreas, and 41% for thyroid. Kidneys exhibited the maximum dose increment, whereas the pancreas showed the widest variance because of the differences in fibro-fatty involution. Finally, thyroids with high attenuation values on unenhanced CT showed a lower Hounsfield unit increase and, thus, a smaller increment in the dose.
  
  
  CONCLUSIONS
  Our study showed an increase in radiation dose in several parenchymatous tissues on contrast-enhanced CT. Our method allowed us to evaluate the dose increase from the change in attenuation measured in Hounsfield units. Because diagnostic protocols require multiple acquisitions after the contrast agent administration, such a dose increase should be considered when optimizing these protocols.
authors.affiliation: Section of Radiological Sciences, Department of Biomedical Sciences and Morphologic and Functional Imaging, University of Messina, Via Consolare Valeria 1, Messina I-98125, Italy. eamato@unime.it
authors.forename: Ernesto
authors.initials: E
authors.lastname: Amato
authors.forename: Ignazio
authors.initials: I
authors.lastname: Salamone
authors.forename: Serena
authors.initials: S
authors.lastname: Naso
authors.forename: Antonio
authors.initials: A
authors.lastname: Bottari
authors.forename: Michele
authors.initials: M
authors.lastname: Gaeta
authors.forename: Alfredo
authors.initials: A
authors.lastname: Blandino
mesh_terms: D003287:Contrast Media / Q000493:pharmacokinetics*; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D007668:Kidney / Q000528:radiation effects; D008099:Liver / Q000528:radiation effects; D009010:Monte Carlo Method; D010179:Pancreas / Q000528:radiation effects; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D012189:Retrospective Studies; D013154:Spleen / Q000528:radiation effects; D013961:Thyroid Gland / Q000528:radiation effects; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide