[Derivation of the optimum exposure condition for Guthmann-method by the fuzzy measure theory].
Journal:
Nihon Hoshasen Gijutsu Gakkai zasshi
Published Date:
Apr 1, 2015
Abstract
The purpose of this study is to decide the optimum exposure condition of Guthmann-method by the fuzzy measure theory. The samples for the fuzzy measure theory were created using the pelvis-phantom irradiated with various tube voltages (90-120 kV) and additional filters (0.5 mmAl+0.05 mmCu, 0.5 mmAl+0.1 mmCu). And we selected 6 samples on each exposure condition. The measuring points of Guthmann-method were specified as primary objective points. Sharpness, graininess and contrast were evaluated in each point. The fuzzy numerical integration was calculated with the rating score of each quality factor and the fuzzy measure. We set threshold to the fuzzy numerical integration and extracted the threshold sample which was able to visually recognize the measuring points on each exposure condition. We selected a sample which had the lowest entrance surface dose in the extracted images. And the exposure condition of this sample (110 kV, 5 mAs, 0.5 mmAl+0.05 mmCu) was adopted. The visual evaluation using the fuzzy measure theory may be useful as an examination method of the exposure condition for Guthmann-method.