One other well-known method is the Krenning score system, derived from [111In]Octreotide scintigraphy of gastrointestinal neuroendocrine tumors, which uses the liver and spleen as the reference regions and has been validated in neuroendocrine tumors that are SSTR2 positive for the purpose of assessing candidacy for PRRT28. Here, SSTR2 is linked to neuroendocrine neoplasm.