著者

白石 順二 宇都宮 あかね

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.53, no.6, pp.691-698, 1997-06-20 (Released:2017-06-29)

参考文献数

6

被引用文献数

15 11

---

Several methods of testing statistically significant differences were used to evaluate the usefulness of one diagnostic imaging system compared with any other imaging system using ROC analysis. Comparison of usefulness between conventional methods such as the two-tailed paired t-test and 95% confidence intervals, and Jackknife method for ROC analysis, which was reported a few years ago, were investigated with actual two experimental results from ROC studies. From the testing results, it was considered that conventional methods reguire large numbers of readers in order to improve the reliability of statistically significant test differenxes between the two imaging systems. When determining differences between two kinds of imaging modalities, the use of the Jackknife method was better than conventional methods in terms of the reliability of test results, because conventional methods do not consider variances between readers and case samples.

著者

白石 順二 花岡 信子 宇都宮 あかね 上田 容子 津田 和良

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.53, no.1, pp.19-24, 1997-01-20 (Released:2017-06-29)

参考文献数

4

被引用文献数

2 1

---

The relationship between gantry angle and the interval length of the scanning plane in computed tomography(CT)was studied with a simple geometrical calculation and the evaluation of clinical images obtained with a human phantom. The change in patient dose was also evaluated under various conditions of gantry angle. When the same table feeding distance was used, it was theoretically and experimentally demonstrated that the interval length of the scanning plane was significantly decreased as the gantry angle increased(e.g.about 10% at twenty-five degrees). Integrated patient dose during the sequence could be changed by various combinations of gantry angle and table feeding distance, and was decreased by setting an optimal interval length of scanning plane according to the gantry angle. We concluded that gantry angle had obvious effects on the interval length of the scanning plane and patient dose, and the new method of increasing the table feeding distance according to the gantry angle might be useful for the improvement of image reproduction and the reduction of patient dose.