Besides iodine-131, several other radioactive isotopes are commonly used in cancer therapy, each with unique properties that make them suitable for targeting specific types of tumors or cancer cells. These isotopes deliver radiation directly to cancerous tissues, minimizing damage to surrounding healthy cells by emitting particles that have limited travel distance in the body.
**Radium-223** is widely used for treating prostate cancer that has metastasized to the bones. This isotope mimics calcium and selectively targets bone areas affected by cancer, delivering alpha particles which cause lethal DNA damage within a very short range. This targeted approach helps reduce pain and control tumor growth in bone metastases.
**Yttrium-90** is another important isotope employed mainly in lymphoma treatment. It is often attached to monoclonal antibodies (such as ibritumomab tiuxetan) that specifically bind to proteins on lymphoma cells like CD20. Once bound, Yttrium-90 emits beta particles that destroy these malignant lymphocytes while sparing most normal tissue.
For neuroendocrine tumors—cancers arising from hormone-producing cells—**Lutetium-177 dotatate** has become a key therapeutic agent. Lutetium-177 emits beta radiation and is linked to molecules targeting somatostatin receptors found on many neuroendocrine tumor cells. This allows precise delivery of radiation directly into the tumor environment.
In advanced prostate cancers resistant to conventional therapies, **Lutetium-177 vipivotide tetraxetan (Lu-177 PSMA)** targets prostate-specific membrane antigen (PSMA), a protein highly expressed on prostate cancer cell surfaces. By binding PSMA, this radiopharmaceutical delivers cytotoxic radiation selectively inside metastatic lesions throughout the body.
Other isotopes also play roles depending on tumor type and location:
– **Cobalt-60**, historically significant for external beam radiotherapy machines, produces gamma rays used primarily for deep-seated tumors.
– **Selective Internal Radiation Therapy (SIRT)** uses microspheres loaded with radioactive isotopes such as yttrium-90 injected into arteries supplying liver tumors; this technique treats unresectable primary liver cancers or metastases by embolizing blood flow while irradiating tumors internally.
These treatments represent advances over traditional external beam radiation because they combine molecular targeting with localized emission of alpha or beta particles — forms of ionizing radiation effective at breaking DNA strands within malignant cells but limited enough not to extensively harm nearby healthy tissue.
Radiopharmaceutical therapy continues evolving rapidly with ongoing research exploring new isotopes and molecular carriers designed for different cancers beyond those currently treated effectively by iodine‑131 alone. The goal remains improving precision so patients receive maximal therapeutic benefit with minimal side effects through personalized nuclear medicine approaches tailored specifically against their tumor’s biological markers and spread pattern.
