Radionuclide

  • 89Sr t1/2: 50.5 days
    Energies: 1463 keV (max), 583.3 keV (mean)
    Type: β, fission product
  • 153Sm t1/2: 46.7 hours
    Energies: β 632, 702, 805 keV (max), 198, 224, 263 keV (mean), γ 103 keV
    Type: β, γ, fission product (neutron irradiation of 152Sm)
  • 32P t1/2: 14.26 days
    Energies: 1710 keV (max), 694.9 keV (mean)
    Type: β, fission product

Radiopharmaceutical

  • 89Sr-chloride
  • 153Sm-lexidronam (ethylenediamine tetramethylene phosphonate
    [EDTMP])
  • 32P-sodium phosphate

Localization

  • 89Sr: Uptake of strontium at sites of osteoblastic skeletal metastases remaining in the same concentration for 100 days after injection. Metastron® (89Sr-chloride) behaves like calcium analogs, preferentially localizing in areas of active osteogenesis.
  • 153Sm: Phosphonate compounds concentrate in bone mineral. Metallic ions are chelated with phosphonate complexes, with the resulting compound used to deliver metallic radioactive ions to bone mineral turnover in association with hydroxyapatite. Quadramet® (153Sm-lexidronam) accumulates in osteoblastic lesions at a 5:1 ratio compared with normal bone.
  • 32P: Phosphate compound with similar characteristics of other phosphate products. A concern is with involvement in metabolic processes, especially within the hematopoietic system causing a high level of myelosuppression.

Quality Control

  • Radiochemical purity must be ≥ 90%
  • 32P: 100% radiochemical purity

Adult Dose Range

  • 89Sr: 4 mCi (148 MBq) or 40–60 µCi (1.48–2.22 MBq) per kg
  • 153Sm: 1 mCi (37 MBq) per kg
  • 32P: 5–10 mCi (185–370 MBq) intravenously or 10–12 mCi (370–740 MBq) PO
  • Some calculate doses on lean body mass, reducing for azotemia or increasing with diffuse widespread metastasis. Some divide the administrations over a period of time.

Method of Administration

  • It is suggested that the syringe be shielded with a lead syringe shield rather than plastic, even though Sr-89 is a pure β emitter.
  • Existing IV catheter or 21-gauge butterfly.
  • Three-way stopcock.
  • Ten milliliters of flush or more. It is suggested to flush the radiopharmaceutical syringe several times to ensure the entire dose is administered.
  • Performed by authorized user: nuclear physician, radiologist, or ordering physician.

Indications

  • Palliation of intractable bone pain for patients with two or more osseous metastases (osteoblastic metastatic bone lesions) documented by bone scan from primary cancer. Candidates should have multiple bone metastases sites, bone pain, white blood cell (WBC) count of > 2400, and a platelet count of > 60,000. Other candidates are those who have failed hormonal therapy for prostate cancer management.
  • Assessment of painful bone metastases for the use of palliation in conjunction with, or instead of, radiotherapy.

Contraindications

  • Patients with no bone pain, multiple sites of metastases, WBC counts of < 2400, platelet counts of < 60,000, or doing well with other methods of pain palliation.
  • A solitary metastatic site.
  • Pregnancy.
  • Patients with evidence of seriously compromised bone marrow from previous therapy or disease infiltration.
  • Quadramet®: Patients who have a known hypersensitivity to EDTMP or similar phosphonate compounds.
  • No contraindications are indicated for the following:
    • Previous heavy external beam irradiation.
    • Previous failure of 89Sr therapy.
    • Anemia; can be corrected by infusion.
    • Conventional methods of pain palliation (e.g., analgesics, nonsteroidal antiinflammatory drugs, hormonal therapy, and radiotherapy) that have not yet been used or are being used and have not yet failed.

Patient Preparation

  • Identify the patient. Verify doctor’s order. Explain the procedure.
  • Ensure patient has and reads package insert information.
  • Obtain a signed, informed consent from patient.
  • Patient to bring results of latest laboratory tests.
  • Patient to bring images and results of latest bone scan (within the last 6 weeks).
  • Instruct patients with incontinence as to toilet instructions and if necessary, catheterize 2 days before injection.
  • Instruct patient to ingest 500 mL of fluid before injection and to void often before and after injection.