key term - Yttrium-90

Definition

Yttrium-90 (90Y) is a radioactive isotope of the element yttrium, which is commonly used in medical applications due to its unique nuclear properties. It is a beta-emitting radioisotope that has become an important tool in the field of radiotherapy, particularly in the treatment of various types of cancer.

5 Must Know Facts For Your Next Test

1. Yttrium-90 has a half-life of 64.1 hours, which makes it suitable for medical applications that require a relatively short-lived radioisotope.
2. The beta particles emitted by yttrium-90 have a maximum energy of 2.28 MeV, which allows for deep tissue penetration and effective treatment of solid tumors.
3. Yttrium-90 is often used in targeted radiotherapy, where it is attached to specific molecules or antibodies that can selectively bind to cancer cells, delivering the radiation directly to the tumor site.
4. One of the primary medical applications of yttrium-90 is in the treatment of liver cancer, particularly in the form of selective internal radiation therapy (SIRT), where the radioisotope is delivered directly to the liver through the hepatic artery.
5. Yttrium-90 is also used in the treatment of other types of cancer, such as non-Hodgkin's lymphoma, through the use of radioimmunotherapy, where the radioisotope is coupled with monoclonal antibodies that target cancer cells.

Review Questions

• Explain the significance of yttrium-90's half-life in its medical applications.
  • The relatively short half-life of yttrium-90, which is 64.1 hours, makes it well-suited for medical applications that require a radioisotope with a limited lifespan. This ensures that the radiation exposure to the patient is minimized, as the radioisotope will decay quickly after being administered, reducing the overall radiation dose. The short half-life also allows for more precise timing and targeting of the radiation therapy, as the radioisotope can be delivered directly to the tumor site without prolonged exposure to surrounding healthy tissues.
• Describe the mechanism of action of yttrium-90 in targeted radiotherapy for cancer treatment.
  • In targeted radiotherapy, yttrium-90 is attached to specific molecules or antibodies that can selectively bind to cancer cells. This allows the radiation to be delivered directly to the tumor site, maximizing the damage to cancer cells while minimizing the exposure to healthy tissues. The high-energy beta particles emitted by yttrium-90 can penetrate deep into the tumor, effectively destroying the cancer cells from within. This targeted approach enhances the efficacy of the radiation therapy and reduces the side effects commonly associated with traditional radiation treatments.
• Analyze the advantages of using yttrium-90 in selective internal radiation therapy (SIRT) for the treatment of liver cancer.
  • The use of yttrium-90 in SIRT for liver cancer treatment offers several advantages. By delivering the radioisotope directly to the liver through the hepatic artery, the radiation is concentrated in the tumor site, reducing exposure to the rest of the body. The high-energy beta particles emitted by yttrium-90 can effectively target and destroy the cancer cells within the liver, while the short half-life ensures that the radiation exposure is limited. Additionally, SIRT with yttrium-90 is less invasive than traditional liver cancer treatments, such as surgery or external beam radiation therapy, making it a more accessible and potentially safer option for patients.

Related terms

Radioisotope: A radioactive isotope of an element that undergoes radioactive decay, emitting ionizing radiation in the form of alpha, beta, or gamma rays.

Beta Decay:

A type of radioactive decay in which a neutron in the nucleus of an atom is converted into a proton, an electron, and an antineutrino, resulting in the emission of a beta particle.

Radiotherapy: A type of cancer treatment that uses high-energy radiation, such as X-rays, gamma rays, or charged particles, to destroy cancer cells and shrink tumors.