Radiation absorbed dose efficacy of 177Lu-DOTATATE in radionuclide therapy of neuroendocrine tumors: a hybrid study of patient and simulation.

Recent developments in targeted radiopharmaceuticals offer promising options for diagnosis and treatment by specifically targeting the overexpressed somatostatin receptors in neuroendocrine tumors (NETs). This study aims to assess the radiation absorbed dose efficacy of 177Lu-DOTATATE in radionuclide therapy of NETs. Four patients were selected for imaging using 177Lu-octreotide or DOTATATE via Single photon emission computed tomography/Computed tomography (SPECT/CT). The absorbed doses were calculated employing the Medical Internal Radiation Dose (MIRD) method and S-value tables associated with 177Lu, utilizing the GEANT4 Application for Tomographic Emission (GATE) calculation code. The mean percentage differences in the S-values between the GATE and IDAC2.1 calculation methods were -0.7 for S (Spleen→Spleen), -3.5 for S (Kidneys→Kidneys), and 4.9 for S (Liver→Liver). The mean absorbed doses from the GATE were 0.076, 0.20, 0.29, and 0.47 mGy/MBq for the liver, kidneys, spleen, and tumors, respectively. Assessment of the results obtained from the GATE code as a voxel-level dose calculation tool in non-uniform media showed that 177Lu-DOTATATE may provide beneficial therapeutic effects.