Participants with known brain metastases Participants with known metastases Participants with known brain metastases should be excluded; screening for brain metastases with head imaging is not required Participants with > 6 definitive lesions consistent with brain metastases Known intracranial metastases ENROLLMENT TO THE DOSE ESCALATION, EXPANSION AND PART II: Participants with known untreated brain metastases are excluded; patients with a history of brain metastases are permitted to enroll if they have been treated, are no longer taking corticosteroids, and have been stable for a minimum of one month on imaging; exceptions for participants with asymptomatic sub-centimeter metastases that, in the opinion of the treating investigator, do not require intervention may be possible following discussion and agreement with the overall principal investigator Participants with known untreated brain metastases should be excluded from this clinical trial; participants with a history of brain metastases that have been treated, are no longer taking corticosteroids, and have been stable on imaging for >= 4 weeks following the last date of treatment are permitted Participants with known untreated brain metastases should be excluded from this clinical trial; participants with a history of brain metastases that have been treated, are no longer taking corticosteroids, and have been stable on imaging for >= 4 weeks following the last date of treatment are permitted Participants with known untreated brain metastases should be excluded from this clinical trial; participants with a history of brain metastases that have been treated, are no longer taking corticosteroids, and have been stable on imaging for at least one month following the end of treatment are permitted. Participants with known brain metastases should be excluded Participants with active brain metastases Have no known metastases Patients with known brain metastases should be excluded Subjects with known metastases Patients with known brain metastases (treated or not) will be excluded Patients with known MIBG-avid parenchymal brain metastases are excluded Patients with known brain metastases are excluded Patients with known metastases are not eligible Participants with known uncontrolled brain metastases will be excluded from this clinical Participants with known brain metastases PHASE II: Participants with known brain metastases should be excluded Participants with known brain metastases Participants with known brain metastases Participants with known brain metastases Any known metastases Known presence of metastases Participants with metastases Patients with known brain metastases are excluded from this study Patients with known brain metastases will be excluded Participants with known brain metastases that are symptomatic and require corticosteroids are excluded Participants with known brain metastases Participants with known brain metastases, or any other metastases from cancer Participants with known uncontrolled brain metastases