ATC Group: V10X Other therapeutic radiopharmaceuticals

Iobenguane is similar in structure to the neurotransmitter norepinephrine (NE) and is subject to the same uptake and accumulation pathways as NE. Pheochromocytoma and paraganglioma (PPGL) are tumors of neural crest origin that express high levels of the NE transporter on their cell surfaces. Following intravenous administration, iobenguane ¹³¹I is taken up and accumulates within pheochromocytoma and paraganglioma cells, and radiation resulting from radioactive decay of ¹³¹I causes cell death and tumor necrosis.

Lutetium (¹⁷⁷Lu) oxodotreotide has a high affinity for subtype 2 somatostatin receptors (sst2). It binds to malignant cells which overexpress sst2 receptors. Lutetium-177 (¹⁷⁷Lu) is a βemitting radionuclide with a maximum penetration range in tissue of 2.2 mm (mean penetration range of 0.67 mm), which is sufficient to kill targeted tumour cells with a limited effect on neighbouring normal cells.

Radium-223 dichloride mimics calcium and selectively targets bone, specifically areas of bone metastases, by forming complexes with the bone mineral hydroxyapatite. Radium-223 dichloride monotherapy or in combination with luteinising hormone releasing hormone (LHRH) analogue is indicated for the treatment of adult patients with metastatic castration-resistant prostate cancer (mCRPC).

Iodide is actively transported by the sodium-iodide symporter (NIS) protein, in thyroid follicular cells. Sodium iodide ¹³¹I is used for the treatment of hyperthyroidism and selected cases of thyroid carcinoma. The beta emission of I 131 is responsible for the therapeutic effect.