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. 2023 Jul 21;5(4):e220157. doi: 10.1148/rycan.220157

Figure 9:

Actinium 225 (225Ac) prostate-specific membrane antigen (PSMA) α-particle therapy following lutetium 177 (177Lu) PSMA-617 β-particle therapy. Images in a 71-year-old man with widely metastatic prostate cancer, with a Gleason score of 7 (3 + 4), that progressed despite androgen deprivation therapy, taxane-based chemotherapy, and thoracic spine stereotactic radiation. (A) Baseline gallium 68 (68Ga) PSMA-11 PET/CT image demonstrates intense PSMA uptake in many nodal metastases (blue arrows). (B) Following three cycles of the targeted β-particle therapy with 177Lu-PSMA-617, the 68Ga-PSMA-11 PET/CT image demonstrates persistent PSMA-avid disease (blue arrows), with a mild reduction in prostate-specific antigen (PSA). (C) Following three cycles of the targeted α-particle therapy with 225Ac-PSMA-617, nearly complete resolution of uptake in the nodal metastases is observed (blue arrows in the location of previous nodal uptake), with a substantial reduction in PSA level.

Actinium 225 (225Ac) prostate-specific membrane antigen (PSMA) α-particle therapy following lutetium 177 (177Lu) PSMA-617 β-particle therapy. Images in a 71-year-old man with widely metastatic prostate cancer, with a Gleason score of 7 (3 + 4), that progressed despite androgen deprivation therapy, taxane-based chemotherapy, and thoracic spine stereotactic radiation. (A) Baseline gallium 68 (68Ga) PSMA-11 PET/CT image demonstrates intense PSMA uptake in many nodal metastases (blue arrows). (B) Following three cycles of the targeted β-particle therapy with 177Lu-PSMA-617, the 68Ga-PSMA-11 PET/CT image demonstrates persistent PSMA-avid disease (blue arrows), with a mild reduction in prostate-specific antigen (PSA). (C) Following three cycles of the targeted α-particle therapy with 225Ac-PSMA-617, nearly complete resolution of uptake in the nodal metastases is observed (blue arrows in the location of previous nodal uptake), with a substantial reduction in PSA level.