Estimation of Radiation Exposure of 128-Slice 4D-Perfusion CT for the Assessment of Tumor Vascularity

Objective: We aimed to estimate the effective dose of 4D-Perfusion-CT protocols of the lung, liver, and pelvis for the assessment of tumor vascularity. Materials and Methods: An Alderson-Rando phantom equipped with thermoluminescent dosimeters was used to determine the effective dose values of 4D-Perfusion-CT. Phantom measurements were performed on a 128-slice singlesource scanner in adaptive 4D-spiral-mode with bidirectional table movement and a total scan range of 69 mm over a time period of nearly 120 seconds (26 scans). Perfusion measurements were simulated for the lung, liver, and pelvis under the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80 kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs). Results: Depending on gender, the evaluated body region and scan protocol, an effective whole-body dose between 2.9-12.2 mSv, was determined. The radiation exposure administered to gender-specific organs like the female breast tissue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in the female specific dose by 86% and 100% in perfusion scans of the lung and the pelvis, respectively. Conclusion: Due to a significant radiation dose of 4D-perfusion-CT protocols, the responsible use of this new promising technique is mandatory. Gender- and organ-specific differences should be considered for indication and planning of tumor perfusion scans.