Domain III(D): Understand characteristics indications, contraindications, & administration of therapeutic radiopharmaceuticals

- targets sodium iodide co-transporter (NIS)

- found in thyroid follicular cells, gastric mucosa, salivary glands, breast tissue, choroid plexus

I-131 sodium iodide mechanism of localization

- thyroid cancer therapy

- thyroid uptake studies

- hyperthyroidism (Grave's disease, toxic nodular goiter)

I-131 sodium iodide indications

- pregnancy/nursing

- severe uncontrolled thyrotoxicosis

I-131 sodium iodide contraindications

oral

I-131 sodium iodide administration

- targets somatostatin receptors (SSTR)

- internalized into neuroendocrine tumor cells after binding

Lu-177 dotatate (Lutathera®) mechanism of localization

treatment of SSTR positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs)

Lu-177 dotatate (Lutathera®) indication

- pregnancy / nursing

- discontinue long-acting octreotide for 4 weeks, & short-acting octreotide for 24 hours:

(can continue 4-24 hours after administration)

(somatostatin analogs that will compete, attaching to SSTR on NET)

Lu-177 dotatate (Lutathera®) contraindications

- amino acids administered 30 minutes prior to decrease radiation dose to kidneys

(start 30 mins prior & infuse over 4 hours)

(anti-emetic administered 30 minutes before amino acids)

- 200 mCi every 8 weeks for total of 4 doses

- can be modified to 100 mCi & longer interval, with reescalation possible

Lu-177 dotatate (Lutathera®) administration

- targets prostate-specific membrane antigen (PSMA)

- PSMA is overexpressed in >90% of prostate cancer cells, particularly in metastatic castration-resistant prostate cancer (mCRPC)

Lu-177 Vipivotide tetraxetan (Pluvicto®) mechanism of localization

treatment of PSMA-positive castration-resistant prostate cancer in patients who have:

- previously received androgen receptor pathway inhibition

- received taxane-based chemotherapy

Lu-177 Vipivotide tetraxetan (Pluvicto®) indications

- PSMA imaging is negative (inadequate uptake)

- bone marrow suppression

- renal impairment

- pregnancy / nursing

Lu-177 Vipivotide tetraxetan (Pluvicto®) contraindications

IV infusion: up to 6 cycles, 6 weeks apart

Lu-177 Vipivotide tetraxetan (Pluvicto®) administration

- mimics calcium, targets bone turnover in hydroxyapatite of bone matrix

- delivers LET alpha particles to tumor sites in bone

Ra-223 Radium dichloride (Xofigo®) mechanism of localization

- palliative care for bone pain

- therapy: castration-resistant prostate cancer, symptomatic bone metastases & no known visceral metastases

Ra-223 Radium dichloride (Xofigo®) indications

- pregnancy / nursing

- bone marrow suppression

- visceral metastases

Ra-223 Radium dichloride (Xofigo®) contraindications

- IV: slow push over 1 minute

- up to 6 injections, every 4 weeks

Ra-223 Radium dichloride (Xofigo®) administration

mimics calcium, localizing in areas of increased osteoblastic activity, particularly metastatic bone lesions

Sr-89 chloride (Metastron®) mechanism of localization

palliative care for bone pain (especially from prostate cancer & breast cancer)

Sr-89 chloride (Metastron®) indication

pregnancy / nursing

Sr-89 chloride (Metastron®) contraindication

- IV injection, typically over 1-2 minutes

- single administration, may be repeated every 3 months

Sr-89 chloride (Metastron®) administration

embolization: microspheres become trapped in the tumor vasculature due to tumor's increased arterial blood supply (targets mechanical pathway)

Y-90 microspheres (SIR-Spheres®, TheraSphere®) mechanism of localization

- unresectable hepatocellular carcinoma (HCC)

- metastatic colorectal cancer to liver

- metastatic neuroendocrine tumors (NETs)

Y-90 microspheres (SIR-Spheres®, TheraSphere®) indications

- pregnancy / nursing

- significant hepatopulmonary shunting (may deliver radiation to lungs)

- uncorrectable gastrointestinal shunting

- total portal vein thrombosis

- severe thrombocytopenia or coragulopathy

Y-90 microspheres (SIR-Spheres®, TheraSphere®) contraindications

intra-arterial injection via catheter into hepatic artery (pre-therapy mapping with Tc-99m MAA)

Y-90 microspheres (SIR-Spheres®, TheraSphere®) administration