Is it possible to use a box/circle for region on interest segmentation on CT-scans?

So basically what I want to do is using a box or region of interest (in 3 different views) to encapsulate a part of the liver/spleen that I want to be segmentated. I tried using the segment editor, but I can’t find the functionality i’m looking for.

Is there also a way to convert a DICOM to a NIFTI file format?

Thanks in advance!

yes I have the same problem to add a feature or a model, then I have a little idea to locate the part you want to segment through the tool CROP VOLUME and to convert DCIM to NIFTI format you can use free online converter

Is there a way that I can use volume rendering to annotate or segment the box that it creates?

So with volume rendering I’m achieving what I want in terms focussing on the region that i want to be segmented/masked and export as a NIFTI file.

I’ve already tried to do, I don’t think there’s any way to do this
volume rendering it only gives you a vision on the segmentation in 3D form