@article{oai:repo.qst.go.jp:00044338,
 author = {Endo, Masahiro and Mori, Shinichiro and Tsunoo, Takanori and Kandatsu, Susumu and Tanada, Shuji and Aradate, Hiroshi and Saito, Yasuo and Miyazaki, Hiroaki and Sato, Kazumasa and Matsushita, Satoshi and Kusakabe, Masahiro and 遠藤 真広 and 森 慎一郎 and 角尾 卓紀 and 神立 進 and 棚田 修二 and 佐藤 一雅 and 松下 聡 and 日下部 正宏},
 issue = {5},
 journal = {IEEE Transactions on Nuclear Science},
 month = {Oct},
 note = {Four-dimensional (4-D) computed tomography (CT) is a dynamic volume imaging system of moving organs with an image quality comparable to conventional CT and it is realized by continuous and high-speed cone-beam CT.  We have developed a novel two-dimensional (2-D) detector for 4-D CT, which is based on the present CT technology, and mounted it on the gantry frame of the state-of-the-art CT-scanner.  In the present paper, we describe the design and the performance evaluation results of the first model of the 4-D CT-scanner.  The X-ray detector for the 4-D CT-scanner is a discrete pixel detector in which pixel data are measured from independent detector elements.  The numbers of elements are 912 (channels) x 256 (segments) and the element size is approximately 1mm x 1mm.  Data sampling rate is 900 views (frames)/s and the dynamic range of the A/D converter is 16 bits.  The rotation speed of the gantry is 1.0 s/rotation.  The data transfer system between rotating and stationary parts in the gantry consists of laser diode and photodiode pairs and it achieves a net transfer speed of 5 Gbps.  Volume data of 512 x 512 x 256 voxels are reconstructed with an Feldkamp-Davis-Kress(FDK) algorithm by parallel use of microprocessors.  The image characteristics such as noise, uniformity, and spatial resolution were evaluated with stationary phantoms in a single rotation.  Exposure dose to an object was measured with an extension of the standard measurement method of CT dose index (CTDI).  Several volunteers were scanned to explore clinical potentials.  For the 4-D CT-scanner, the image characteristics of stationary objects were almost the same as that of conventional CT, while CTDI of the 4-D CT was slightly higher than that of onventional CT.  Isotropic resolving power of less than 0.5 mm was achieved for the stationary object.},
 pages = {1667--1671},
 title = {Development and performance evaluation of the first model of 4D CT-scanner},
 volume = {50},
 year = {2003}
}