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Head CT dose reduction with organ-based tube current modulation
Joji Ota1,2, Hajime Yokota3, Takenori Kobayashi4
1Department of Radiology, Chiba University Hospital, Chiba City, Chiba, Japan.
Medical Physics
|January 21, 2022
Summary
Organ-based tube current modulation (OBTCM) effectively reduces radiation dose to the lens during helical head CT scans. This method visualizes and mitigates increased exposure from double irradiation, enhancing patient safety.
Area of Science:
- Medical Imaging
- Radiological Physics
- Radiation Dosimetry
Background:
- Helical head CT scans with pitch factor <1.0 can lead to double irradiation, potentially increasing lens radiation dose.
- Organ-based tube current modulation (OBTCM) reduces anterior patient dose but visualizing complex double irradiation is challenging.
Purpose of the Study:
- To visualize three-dimensional twice-irradiated areas in helical head CT.
- To clarify the radiation exposure reduction effect of OBTCM in these areas.
Main Methods:
- A leuco crystal violet (LCV) dosimeter in a bottle was used for helical CT scans.
- Scans were performed with and without OBTCM using specific imaging parameters.
- Optical computed tomography (OCT) visualized exposed areas, and dose reduction was calculated.
Main Results:
- LCV dosimeter successfully visualized spiral-shaped twice-irradiated areas.
- Double irradiation increased dose by 15.0-15.9%, which was reduced by OBTCM.
- OBTCM achieved a 29.6% dose reduction at 90° anterolateral.
Conclusions:
- LCV dosimeter effectively visualized and measured dose in complex 3D twice-irradiated areas.
- OBTCM significantly attenuated the increased radiation exposure from double irradiation in helical head CT.
