The layout of the second panel depends on the Mask setting on the INPUT panel. The situation illustrated below represents CT-based masking. Correspondingly, the page is titled CT, and in the lower right the Masking methods appear with a corresponding action button Create CT mask. The situation with MR-based masking is analogous.
Reference Image Loading
Please use the indicated button for loading the anatomical image series. It needs to already be matched to the PET series and to have the origins at the same location. In the case of non-matched data, matching should be performed beforehand using PMOD’s image fusion tool.
The loaded image is immediately cropped to the same box as the PET and interpolated to the same resolution. The correspondence in the resulting images can be verified with the fusion slider.
CT-based Mask
The selection of Masking methods illustrated below is only shown if CT has been chosen for masking on the PET panel.
▪Otsu: This method iteratively looks for the best threshold to separate an object from a background assuming two main gray-level regions.
▪Mean: Includes all pixels above the image mean.
▪% max: Includes all pixels above the specified percentage of the image maximum.
▪Threshold: Includes all pixels above the specified absolute Hounsfield value.
▪Whole-body: This method applies a threshold, followed by morphological operations for removal of the bed and filling of the airways.
▪No masking: Do not apply a mask in the segmentation.
After selecting the method, please proceed with the Create CT mask button in the lower right.
MR-based Mask
If MR has been chosen for masking on the PET panel the Masking methods are similar as described above.
The following methods are MR specific:
▪Whole-body: This procedure calculates the image log-values and derives a threshold from the histogram.
After selecting the method, please proceed with the Create MR mask button in the lower right.
PET-based Mask
With PET-based masking the panel is labeled CT | MR. Please load the reference image with Load Anatomical, and proceed with Create PET mask.