P106] CT dose distribution of 10 cm (infants) and 16 cm (adults) by a head CT phantom

Abstract

It is important to reduce X-ray dose in diagnostic radiology such as CT examination. In order to evaluate the head CT dose distribution of infants and adults. The diameters of the created two half cylindrical acrylic phantoms were 10 cm (infants) and 16 cm (adults). The Gafchromic film was sandwiched between the half of cylindrical acrylic phantoms. The head CT scan parameters were as follows; single scan, 2 cm scan thickness, 120 kV tube voltage, 300 mA tube current, and 1 s of rotation (Aquilion Toshiba Co., Japan). After head CT irradiation, the Gafchromic XR-QA2 film was scanned using an image scanner (EPSON ES-10000G, Seiko Epson Co., Nagano, Japan). Scanning data were analyzed in pixel values by image analysis application image J (National Institute of Health, Bethesda, MD), and CT dose distribution was evaluated. The pixel values of the CT irradiated area indicated the lowest value at the center of the phantom, gradually increased the pixel value to the surface of the phantom continuously. The ratio of the surface/center was 1.05 times for the infant’s phantom, and was 1.15 times for the adult’s phantom. The dose distribution in the head CT of infant’s and adult’s phantoms were evaluated using the half of cylindrical acrylic phantoms with Gafchromic XR-QA2 film. Dose distribution of the CT is able to evaluate using this method.