Kostas Perisinakis1,2, Antonis Tzedakis3, Kostas Spanakis4, Antonios E Papadakis3, Adam Hatzidakis4,5, John Damilakis6,3. 1. Department of Medical Physics, Medical School, University of Crete, P.O. Box 2208, 71003, Heraklion, Crete, Greece. kostas.perisinakis@med.uoc.gr. 2. Department of Medical Physics, University Hospital of Heraklion, P.O. Box 1352, 71110, Heraklion, Crete, Greece. kostas.perisinakis@med.uoc.gr. 3. Department of Medical Physics, University Hospital of Heraklion, P.O. Box 1352, 71110, Heraklion, Crete, Greece. 4. Department of Radiology, University Hospital of Heraklion, P.O. Box 1352, 71110, Heraklion, Crete, Greece. 5. Department of Radiology, Medical School, University of Crete, P.O. Box 2208, 71003, Heraklion, Crete, Greece. 6. Department of Medical Physics, Medical School, University of Crete, P.O. Box 2208, 71003, Heraklion, Crete, Greece.
Abstract
OBJECTIVES: To investigate the effect of iodine uptake on tissue/organ absorbed doses from CT exposure and its implications in CT dosimetry. METHODS: The contrast-induced CT number increase of several radiosensitive tissues was retrospectively determined in 120 CT examinations involving both non-enhanced and contrast-enhanced CT imaging. CT images of a phantom containing aqueous solutions of varying iodine concentration were obtained. Plots of the CT number increase against iodine concentration were produced. The clinically occurring iodine tissue uptake was quantified by attributing recorded CT number increase to a certain concentration of aqueous iodine solution. Clinically occurring iodine uptake was represented in mathematical anthropomorphic phantoms. Standard 120 kV CT exposures were simulated using Monte Carlo methods and resulting organ doses were derived for non-enhanced and iodine contrast-enhanced CT imaging. RESULTS: The mean iodine uptake range during contrast-enhanced CT imaging was found to be 0.02-0.46% w/w for the investigated tissues, while the maximum value recorded was 0.82% w/w. For the same CT exposure, iodinated tissues were found to receive higher radiation dose than non-iodinated tissues, with dose increase exceeding 100% for tissues with high iodine uptake. CONCLUSIONS: Administration of iodinated contrast medium considerably increases radiation dose to tissues from CT exposure. KEY-POINTS: • Radiation absorption ability of organs/tissues is considerably affected by iodine uptake • Iodinated organ/tissues may absorb up to 100 % higher radiation dose • Compared to non-enhanced, contrast-enhanced CT may deliver higher dose to patient tissues • CT dosimetry of contrast-enhanced CT imaging should encounter tissue iodine uptake.
OBJECTIVES: To investigate the effect of iodine uptake on tissue/organ absorbed doses from CT exposure and its implications in CT dosimetry. METHODS: The contrast-induced CT number increase of several radiosensitive tissues was retrospectively determined in 120 CT examinations involving both non-enhanced and contrast-enhanced CT imaging. CT images of a phantom containing aqueous solutions of varying iodine concentration were obtained. Plots of the CT number increase against iodine concentration were produced. The clinically occurring iodine tissue uptake was quantified by attributing recorded CT number increase to a certain concentration of aqueous iodine solution. Clinically occurring iodine uptake was represented in mathematical anthropomorphic phantoms. Standard 120 kV CT exposures were simulated using Monte Carlo methods and resulting organ doses were derived for non-enhanced and iodine contrast-enhanced CT imaging. RESULTS: The mean iodine uptake range during contrast-enhanced CT imaging was found to be 0.02-0.46% w/w for the investigated tissues, while the maximum value recorded was 0.82% w/w. For the same CT exposure, iodinated tissues were found to receive higher radiation dose than non-iodinated tissues, with dose increase exceeding 100% for tissues with high iodine uptake. CONCLUSIONS: Administration of iodinated contrast medium considerably increases radiation dose to tissues from CT exposure. KEY-POINTS: • Radiation absorption ability of organs/tissues is considerably affected by iodine uptake • Iodinated organ/tissues may absorb up to 100 % higher radiation dose • Compared to non-enhanced, contrast-enhanced CT may deliver higher dose to patient tissues • CT dosimetry of contrast-enhanced CT imaging should encounter tissue iodine uptake.
Authors: Babs M F Hendriks; Roald S Schnerr; Gianluca Milanese; Cécile R L P N Jeukens; Sandra Niesen; Nienke G Eijsvoogel; Joachim E Wildberger; Marco Das Journal: Korean J Radiol Date: 2019-02 Impact factor: 3.500
Authors: Cécile R L P N Jeukens; Hub Boere; Bart A J M Wagemans; Patty J Nelemans; Estelle C Nijssen; Rebecca Smith-Bindman; Joachim E Wildberger; Anna M Sailer Journal: BMJ Open Date: 2021-01-17 Impact factor: 2.692