I.B.M., which was one of the great business organizations in history, and which was perfectly placed to own the personal-computer business, disastrously failed to appreciate the importance of the software Gates designed for it.
Of the small-animal PET scans, 71% exhibited quantifiable motion after software gating.
The software gating COM measurements lying below this threshold were considered to possibly be an expression of noise only.
Further scrutiny revealed that modifications to the frequency window parameter used in the software gating process could fix the error.
(MPEG 1 MB) Additional file 3: Figure S3: Examples of maximum-intensity projection images created using automated software gating, gating+ signal combination, and phase offset (30 frames/s) processes.
Those software gating COM measurements lying above this cutoff (n = 60/84, 71%) were considered to reflect respiratory motion identified by gating.
This threshold was used to characterize the scans (those lying above the line) that were enhanced with motion as a result of software gating.
With hardware gating, results are variable with respect to the placement of monitoring devices and particular patient geometry/behavior, and parameter optimization in software gating can be understood as analogous.
In addition to extending software gating methods to preclinical PET, this work also addressed a fundamental consequence of gating: that gated images include less motion, but also fewer counts.
Our work demonstrated to us, however, that there may be a large advantage with software gating in that scans can be reprocessed retrospectively in an effort to achieve an optimal signal.
