Inclusion criteria:

          -  Signed informed consent.

          -  Subjects of either sex, aged ≥18 years.

          -  ECOG status 0-2.

          -  Life-expectancy of at least 12 weeks.

          -  Histologically/cytologically confirmed diagnosis of SSTR (+) neuroendocrine tumors of
             the lung, Pheochromocytoma, Paraganglioma, thymus, and unknown primary, unresectable
             or metastatic.

          -  Measurable disease per RECIST 1.1, on CT/MRI scans, defined as at least 1 lesion with
             ≥ 1 cm in longest diameter (lymph nodes along short axis >15 mm).

          -  Appropriate diagnostic imaging studies, at the discretion of the P.I. including but
             not limited to CT, MRI , 18F-FDG PET/CT, NAF PET/CT bone scan, ultrasound, etc. of the
             tumor region or suspected area within the 4 weeks of dosing day.

          -  Somatostatin receptor positive (SSTR+) disease, as evidenced by available FDA,
             commercially of IND approved SSTR imaging (SRI), within 4 weeks prior to the first
             cycle

          -  Recent blood test results (within 2weeks pre-dose) as follows:

          -  Sufficient bone marrow capacity as defined by WBC ≥2,500/µl and WBC≥2,000/mm3 for
             subsequent cycles; platelets ≥ 100,000 (100 * 103/mm3) for the first treatment and
             ≥75,000 for the subsequent therapies, Hgb ≥8.9 g/dl for the first treatment and 8.0
             g/dl for the subsequent therapies, ANC ≥1500/mm3 for the first treatment and ≥1000/
             mm3; for the subsequent therapies.

          -  ALT, AST values ≤3 times ULN

          -  Bilirubin: ≤3 times ULN

          -  Serum creatinine ≤ 150 µmol/liter or 1.7 mg/dl

          -  Negative pregnancy test in women capable of child-bearing within 48 hours of IMP
             administration.

          -  Serum albumin > 3.0g/L (<3 g/L may be acceptable at the discretion of investigator, if
             PT, PTT, and INR are within normal range)

          -  All available FDA-approved therapies for which the subject is eligible have been
             exhausted (with the exception of PRRT), unless available therapies are refused by the
             subject (with the exception of somatostatin analogue, octreotide, and somatuline).

        Exclusion Criteria:

          -  Known hypersensitivity to any of the excipients of Lu-177 DOTATOC.

          -  Therapeutic use of any somatostatin analogue, including Sandostatin® LAR (within 28
             days) and Sandostatin® (within 1 day) prior to treatment.

          -  Subjects with unusual hematological parameters, including an increased MCV (>105fL),
             and especially in those who had previous chemotherapy, the advice of a hematologist
             should be sought for adequate further work-up

          -  Any subject who is taking concomitant medications that decrease renal function (such
             as aminoglycoside antibiotics).

          -  Female subjects who are pregnant, lactating or women of childbearing potential not
             willing to practice effective contraceptive techniques during the study period and for
             67 days (more than 10 half-lives of 177Lu after the last treatment, or male subjects
             who have female partners of childbearing potential not willing to practice abstinence
             or effective contraception, during the study period and for 67 days after the last
             treatment.

          -  Current somatic or psychiatric disease/condition that may interfere with the
             objectives and assessments of the study.

          -  Indication for surgical lesion removal with curative potential

          -  Planned (for the period of study participation): chemotherapy, immunotherapy,
             radiation therapy (unless regional for pain relief) chemo-embolization, bland
             embolization, radio-embolization, treatment with cyclosporine-A.

          -  Known brain metastases; unless these metastases have been treated and stabilized 6
             months prior to enrolment

          -  Completion of: (1) cytotoxic chemotherapy for less than 6 weeks; (2) a biological
             agent for less than 5 half-lives; and (3) radiation therapy (except regional for pain
             relief) for less than 6 weeks prior to study enrolment,

          -  Uncontrolled congestive heart failure; subjects suspected of having this condition
             need to show ejection fraction of > 35% as determined by MUGA scan.

          -  Glomerular Filtration Rate (GFR) < 35 mL/min

          -  Subjects with prior peptide receptor radionuclide therapy (PPRT).