Inclusion Criteria:

1. Patients with progressive, locally recurrent, or metastatic osteosarcoma (i.e.
high-risk only) with no standard curative options available with at least one
indicator lesion avid on 99mTc-MDP scan will be eligible

2. Anatomic imaging (CT or MRI) of all sites of disease along with chest CT at baseline
and restaging for all patients will be done to allow for assessment of RECIST
progression. RECIST progression will determine progressive disease regardless of
other imaging.

3. Indicator lesion that has uptake of 99mTc-MDP on bone scan and can be subjected to
quantitative assessment by this scans and possibly other means.

4. Age 15 and above and >40 kg.

5. ECOG=2 or better

6. Subjects or their guardians must be able to understand and be willing to sign the
written informed consent form. A signed informed consent form must be appropriately
obtained prior to the conduct of any trial-specific procedure.

7. All acute toxic effects of any prior treatment have resolved to NCI-CTCAE v4.0 Grade
1 or less at the time of signing the Informed Consent Form (ICF).

8. Women of childbearing potential must have a negative serum pregnancy test performed
within 7 days prior to the start of study drug. Post-menopausal women (defined as no
menses for at least 1 year) and surgically sterilized women are not required to
undergo a pregnancy test.

9. Subjects (men and women) of childbearing potential must agree to use adequate
contraception beginning at the signing of the ICF until at least 30 days after the
last dose of study drug. The definition of adequate contraception will be based on
the judgment of the principal investigator or a designated associate.

10. Acceptable hematology and serum biochemistry screening values: White Blood Cell Count
(WBC) >= 1500/mm3; Absolute Neutrophil Count (ANC) >= 1,000/mm3; Platelet (PLT) count
>= 75,000/mm3; Hemoglobin (HGB) >= 8 g/dl; Total bilirubin level <= 1.5 x
institutional upper limit of normal (ULN); Aspartate aminotransferase (AST) and
alanine aminotransferase (ALT) <= 2.5 x ULN; Creatinine <= 1.5 x ULN; Albumin > 25
g/L

11. Willing and able to comply with the protocol, including follow-up visits and
examinations.

12. Patients with progressive, locally recurrent, or metastatic osteosarcoma (i.e.
high-risk only) with at least one indicator lesion avid on 99mTc-MDP scan will be
eligible.

Exclusion Criteria:

1. Diagnosis other than osteosarcoma.

2. 99mTc-MDP bone scan with no significant uptake (i.e. "nothing" for a bone-seeking
isotope to target/ i.e. indicator lesion that would be expected to have the
bone-seeking targeted uptake of 223-radium dichloride).

3. Other malignancy treated within the last 3 years (except non-melanoma skin cancer or
low-grade superficial bladder cancer).

4. Any other serious illness or medical condition, such as but not limited to: Any
active infection ≥ National Cancer Institute Common Terminology Criteria for Adverse
Events (NCI-CTCAE) version 4.03 Grade 2; Cardiac failure New York Heart Association
(NYHA) III or IV; Fecal incontinence (this is because of Ra-223 elimination in
feces).

5. Women who are pregnant or breast-feeding.

6. Inability to comply with the protocol and/or not willing or not available for
follow-up assessments.

7. Any condition which, in the investigator's opinion, makes the subject unsuitable for
trial participation.

8. Concurrent anti-cancer therapy (chemotherapy, radiation therapy, surgery,
immunotherapy, biologic therapy, or tumor embolization)

9. Patients on oxygen.