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The TU/TR/RS domains were created for tumors which in themselves don't belong in any body system domains (tumor can grow and spread to any place), hence they are in their own domains.

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At some point, non-tumor lesion was added to TU/TR. SDTM now has body-system domains,

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it then begs the question whether a separate non-tumor lesion domain is needed, when most "lesions" and things that could be considered as lesions, can go into their respective body-system domains

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. Can the body system domains offer the "unique lesion identifier" through the use of, GRPID, REFID, or other identifier variables?

What goes into TULOC?

After all this, i struggle with what values should go into TULOC. When a CT scans the chest, it produces cross-sectional images of the chest/thorax and everything in it. You can view the images in three angles: a) axial view (you are looking at the picture of the thorax from the direction of head to toe), b) the coronal view (you are looking at the images of the thorax as if you are standing in front of the person),  c) sagittal view (you are looking at the picture of the thorax from the side). Hence TULOCs are populated with Thoracic Region and Abdominal Region for now. Especially in the axial view, as you move from cross-sectional images of the thorax to images of the abdomen, you are looking at sectioned images of the thoracic region to abdominal region, there is no mistake about which region you are looking at because the anatomy of both regions are so different and clearly sperpated. I think it is not wrong to populate TULOC with chest and abdomen as well, they are just not the most precise anatomical terms.

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