Introduction
In nuclear physics, there is a naturally occurring process of the atomic nucleus known as the radioactive decay of the nucleus, and this process is considered one of the basic processes of nuclear energy science. Radioactive decay has several practical applications, and in this article, we will shed light on radioactive decay in the medical field and how to benefit from this process and learn about the medical applications of materials or elements that are exposed to radioactive decay.
Definition of Radioactive Decay
Radioactive decay is a natural process that occurs in an unstable atomic nucleus due to an imbalance between the number of protons and neutrons. To achieve a more balanced state, the unstable nuclei undergo a series of transformations so that they are transformed into more stable configurations by emitting radiation. This radiation consists of alpha particles (helium nuclei), beta particles (high-energy electrons or positrons), gamma rays (high-energy photons), and sometimes neutron emission. The decay process follows a predictable pattern, characterized by a half-life, which is the time it takes for half of the radioactive substance to decay.
Medical Applications of Radioactive Decay
There are several medical applications for elements or materials that undergo radioactive decay, and they are called medical isotopes or radioactive isotopes more precisely. Radioisotopes provide many applications in the medical field, namely:
I) Diagnostic Imaging
Diagnostic imaging is one of the primary uses of radioactive decay in medicine. Medical isotopes, or radioisotopes, are used as tracers in imaging procedures such as single photon emission computed tomography (SPECT) and positron emission tomography (PET). These isotopes emit gamma rays, which can be detected by imaging equipment to create an image of the body's internal structure.
Technetium-99m is the most widely used isotope in medical imaging, accounting for more than 80% of all diagnostic scans. This isotope has a half-life of only six hours, which means it breaks down quickly and doesn't stay in the body for very long. This makes them ideal for imaging procedures, as they can be injected into a patient shortly before the scan and will be largely degraded by the time the scan is complete.
Other isotopes used in medical imaging include iodine-123, gallium-67, and fluorine-18. Each of these isotopes has different decomposition properties and is used for different types of scans.
II) Cancer Treatment
Radioactive decay is also used in the treatment of cancer. Radiation therapy is a common treatment for cancer, which involves directing high-energy radiation at cancer cells to destroy their DNA and stop them from multiplying. This can be accomplished with external beam radiotherapy, in which radiation is delivered from outside the body, or internal beam radiotherapy, in which the radiation source is placed inside the body near the site of the tumor.
Cobalt 60 is one of the most common isotopes used in radiotherapy. This isotope emits high-energy gamma rays that can penetrate deep into the body, making it ideal for treating tumors located deep in the body. Cobalt-60 is typically used in a machine called a teleprocessing unit, which transmits radiation in a highly controlled and focused manner.
Other isotopes used in radiotherapy include iodine-131, which is used to treat thyroid cancer, and strontium-89 and samarium-153, which are used to treat bone cancer.
III) Radioimmunotherapy
Radioimmunotherapy is a targeted treatment that uses radioisotopes attached to antibodies to selectively deliver radiation to cancer cells. Antibodies recognize and bind to specific proteins on the surface of cancer cells, delivering radiation to cancerous tissue while sparing healthy tissue.
One example of radioimmunotherapy is the use of yttrium 90 in the treatment of non-Hodgkin's lymphoma. In this treatment, the patient is injected with a radioactive isotope attached to an antibody that recognizes a protein on the surface of lymphoma cells. Radiation from yttrium-90 damages the DNA of cancer cells, causing them to die.
IV) Therapeutic Agents
Radioactive isotopes can also be used as therapeutic agents in a process called radioisotope therapy. Radioactive pharmaceuticals are designed to selectively accumulate in certain tissues or organs, for example:
- Thyroid Treatment
Radioactive iodine-131 is used to treat certain thyroid conditions, particularly hyperthyroidism and thyroid cancer. Since the thyroid gland absorbs iodine, introducing radioactive iodine into the body allows for targeted destruction of thyroid tissue or cancer cells.
- Bone Pain Palliation
Strontium-89 and samarium-153 are radioactive isotopes used to relieve bone pain caused by metastatic cancer that has spread to the bones. These isotopes emit beta particles that target and damage cancer cells in the bones, thereby alleviating pain.
V) Radiation Sterilization
Radioactive decay is also used to sterilize medical equipment and supplies. This process is most commonly used for items that cannot be sterilized by other means, such as some types of plastics and medical implants. The device is exposed to gamma radiation from a radioactive isotope, which kills any bacteria, viruses, or other microorganisms present.
Cobalt-60 is the most widely used isotope for radiological sterilization, as it emits high-energy gamma rays that can penetrate deeply into the material being sterilized. Other isotopes used for this purpose include cesium-137 and iridium-192.
VI) Radiation Safety and Imaging Devices
Radioactive sources, such as technetium-99, are used in the calibration and quality assurance of medical imaging devices like X-ray machines, CT scanners, and gamma cameras.
Conclusion
In this article, we got acquainted with the radioactive decay of the nucleus and how it is used in medicine, as well as we got acquainted with the basic applications of radioactive decay. It should be noted that the use of radioactive materials in the field of medicine requires strict regulation and adherence to safety protocols to ensure the safety of patients, doctors, and the rest of the hospital staff.
#nuclear_medicine #radioactive_decay #radioactive_decay_medicine #diagnostic_imaging #cancer_treatment #radioimmunotherapy #therapeutic_agents #radiation_sterilization #radiation_safety
