Van Daele M, Joosten J, Devos P, Vandecruys A, Willems J L, De Roo M
Department of Nuclear Medicine, UZ Gasthuisberg, Leuven, Belgium.
Phys Med Biol. 1990 Nov;35(11):1477-85. doi: 10.1088/0031-9155/35/11/004.
In factor analysis, structures are separated on the basis of their temporal behaviour, even if there is a partial overlap. Usually, the temporal behaviour of the system under study cannot be sampled in its true form due to a total overlap by the background. In the ROI (region of interest) method, background subtraction is used as a means to correct the problem. In factor analysis, this problem has been ignored for a long time. We prove that the factor analysis method gives incorrect results when there is a total overlap of a structure. By assuming a local homogeneity of the overlapping structure, we can greatly improve the solution found. Compared with the classical ROI method, our method is operator independent and organ specific.
