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OBJECTIVE. The purpose of this study was to evaluate in phantoms the dose reduction to anterior surfaces and image quality with organ-based tube-current modulation in head and thoracic CT.

MATERIALS AND METHODS. Organ-based tube-current modulation is designed to reduce radiation dose to superficial radiosensitive organs, such as the lens of the eye, thyroid, and breast, by decreasing the tube current when the tube passes closest to these organs. Dose and image quality were evaluated in phantoms for clinical head and thorax examination protocols with and without organ-based tube-current modulation. Surface dose reduction as a function of position was measured using a 32-cm CT dose index (CTDI) phantom, an anthropomorphic adult phantom, and ion chambers. Surface dose reduction as a function of patient size was investigated using three semianthropomorphic phantoms with posteroanterior …