@article{oai:repo.qst.go.jp:00046234,
 author = {Kokuryo, Daisuke and Etsuko, Kumamoto and Takao, Yoshie and Fujii, Susumu and Kaihara, Toshiya and Kuroda, Kagayaki and 國領 大介 and 黒田 輝},
 issue = {1},
 journal = {Magnetic Resonance in Medicine},
 month = {Jun},
 note = {The purpose of this study was to evaluate a novel vessel-tracking-
based technique for tracking of human liver. The novelty of
the proposed technique is that it measures the translation and
deformation of a local tissue region based on the displacements
of a set of vessels of interest instead of the entire organ. The
position of the target point was estimated from the relative positions
of the center-of-masses of the vessels, assuming that the
topological relationship between the target point and center-ofmasses
is unchanged during breathing. To reduce inaccuracy
due to the delay between vessel image acquisition and sonication,
the near-future target position was predicted based on the
vessel displacements in the images extracted from an image
library acquired before the tracking stage. Experiments on
healthy volunteers demonstrated that regardless of the respiratory
condition, appropriate combinations of three center-ofmasses
from the vessels situated around the target-tissue position
yielded an estimation error of less than 2 mm, which was
significantly smaller than that obtained when using a single center-
of-mass trio. The effect of the tracking delay was successfully
compensated, with a prediction error of less than 3 mm, by
using over four images selected from the image library.},
 pages = {156--163},
 title = {Evaluation of a Vessel-Tracking-based Technique for Dynamic Targeting in Human Liver},
 volume = {67},
 year = {2011}
}