This is a prospective, open-label, single-center, dose-escalation study using a standard 3+3 design to assess the safety, tolerability, biodistribution/dosimetry and preliminary efficacy of the albumin-binding PSMA radioligand 161Tb-LNC1011 in patients with metastatic castration-resistant prostate cancer (mCRPC). Patients will receive intravenous 161Tb-LNC1011 starting at 50 mCi with planned dose-level escalations to 80, 130 and 200 mCi (±10%). Early dose levels (50 mCi) receive 1 cycle; later levels receive up to 4 cycles every 6 weeks based on safety and disease status. Primary endpoints include dose-limiting toxicities (DLTs), adverse events (AEs) graded by CTCAE v5.0, and determination of maximum tolerated dose (MTD). Secondary endpoints include organ/tumor absorbed doses, PSA responses (PSA50/PSA90), disease control, time to PSA progression and radiographic progression-free survival per PCWG3.