A SIMPLE METHOD FOR CALIBRATING PIXEL VALUES OF THE CT LOCALIZER RADIOGRAPH FOR CALCULATING WATER-EQUIVALENT DIAMETER AND SIZE-SPECIFIC DOSE ESTIMATE

作者：Anam Choirul; Fujibuchi Toshioh; Toyoda Takatoshi; Sato Naoki; Haryanto Freddy; Widita Rena; Arif Idam; Dougherty Geoff

来源：Radiation Protection Dosimetry, 2018, 179(2): 158-168.

DOI：10.1093/rpd/ncx241

The purpose of this study is to establish the relationship between the pixel value ( I) of the CT localizer radiograph and water-equivalent thickness (t(w)) in a straightforward procedure. We used a body CTDI phantom, which was scanned in the AP and LAT projections. After transformation from the pixel values of the images to tw, water-equivalent diameter (D-w) and size-specific dose estimate were calculated on an anthropomorphic phantom and 30 patients retrospectively. We found a linear correlation between I and tw, with R-2 >= 0.980. The D-w values based on the CT localizer radiograph were comparable to those calculated using axial images. The D-w difference for the anthropomorphic phantom between AP projection and axial images was 5.4 +/- 4.2%, and between LAT projection and axial images was 6.7 +/- 5.3%. The D-w differences for the patients between CT localizer radiograph and axial images was 2.3 +/- 3.2%.

• 出版日期2018-4