Toshiki Adachi

Publications (2)0 Total impact

• Article: [Comparison of detectability of liquid crystal displays (LCDs) and film using phantoms of small adenocarcinomas as abnormalities].

  Yasuo Mochizuki, Shinji Abe, Masahiko Monma, Kojirou Yamaguchi, Toshiki Adachi
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  ABSTRACT: Following the trend of the digitalization of the modalities used for diagnostic imaging, the devices for such imaging have increasingly included monitors. The present study was undertaken to evaluate the usefulness of soft-copy (liquid crystal display; LCD) images of phantoms of small adenocarcinomas using receiver operating characteristic (ROC) analysis of two different display systems: LCD and hard copy (film). A two-tailed paired t-test and the jackknife method (parametric methods) were performed, and no significant differences were found in the area under the ROC curve (AUC) for the pulmonary fields, lungs, ribs, or mediastinum between the film and LCD display systems, and the detectability did not differ between the film and LCD monitors. A Mann-Whitney U test, which is a non-parametric method that applies to the analysis of a small sample, also showed no significant differences in the AUC. The results of this study suggest that LCDs can replace hard-copy film as a display system if the signals.
  Nippon Hoshasen Gijutsu Gakkai zasshi 01/2011; 67(4):328-35.
• Article: [Study of optimal imaging parameters for digitally reconstructed radiographs (DRR) in radiotherapy treatment planning using single-slice helical CT].

  Masanori Matsushima, Toshiki Adachi, Rie Tanaka, Yuzo Kikuchi, Masayoshi Shimoda, Tsuyoshi Yoneda, Tatsuo Yonezawa
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  ABSTRACT: In recent years, by making digitally reconstructed radiographs (DRR) from helical CT images in the position check of an irradiation field, the verification performed by DRR, lineacgraphy (LG), or an electronic portal imaging device (EPID) has become possible. We examined the optimal parameters of single-slice helical scanning in DRR image construction and the usefulness of DRR replaced with the simulation film. We performed a section sensitivity profile at the Z-axis (SSPz) as evaluation of a physical characteristic of helical CT equipment and the form of image of DRR, fixed quantity evaluation of imaging distortion, and visual verification of images. It was determined that DRR was influenced by the partial volume effect depending on slice thickness and pitch, such that this influence occurred when slice thickness and pitch were large. Between a simulation film and DRR reconstructed using imaging parameters with a slice thickness of 3 mm, pitch of 1.0, and reconstruction slice thickness of 3 mm, coincidence was not complete. However, the distortion of DRR was small and the difference was not statistically; thus it was considered to be useful. In conclusion, we consider that DRR reconstructed using the parameters of single-slice helical scanning is useful for clinical evaluation in radiotherapy planning.
  Nippon Hoshasen Gijutsu Gakkai zasshi 05/2004; 60(4):528-36.