Notable success is 177Lu‐DOTATATE for SSTR2‐positive NETs and 177Lu‐PSMA‐617 for mCRPC.[77,78] For PSMA‐directed TRT in mCRPC, 68Ga‐PSMA‐11 PET imaging directs therapy, and response is tracked with follow‐up imaging (SPECT within a short time after treatment or PET for longer follow‐up), demonstrating appreciable declines in tumor burden and PSA (Figure 19).[77,78] Radioiodine (131I) is an archetype theranostic agent for DTC therapy, successfully ablating remaining tissue.[84,144]. The gene discussed is FOLH1; the disease is neoplasm.