Question

Each of the following isotopes has been used medically for the purpose indicated. Suggest reasons why the particular element might have been chosen for this purpose. a. cobalt- \(57,\) for study of the body's use of vitamin \(\mathrm{B}_{12}\) b. calcium- \(47,\) for study of bone metabolism c. iron-59, for study of red blood cell function d. mercury-197, for brain scans before CAT scans became available

Short answer

Cobalt-57 is used for studying the body's use of vitamin B12 due to its radioactive properties, emitting gamma rays, and the cobalt atom present in vitamin B12. Calcium-47 is used for studying bone metabolism because it releases beta rays and is an integral part of bone tissue. Iron-59 is used to study red blood cell function as it emits beta and gamma radiation, and iron is a major component of hemoglobin in red blood cells. Mercury-197 was used for brain scans before CAT scans became available due to its ability to emit gamma rays, cross the blood-brain barrier, and be taken up by brain tissues, allowing for visualization of brain structure and function.

Step-by-step solution

a. Cobalt-57 for the study of the body's use of vitamin B12

Cobalt-57 is a radioactive isotope that emits gamma rays, making it suitable for medical imaging. Vitamin B12 contains a cobalt atom, and as such, it can be replaced with Cobalt-57 to create a radioactively labelled B12. This will allow for the tracking and monitoring of how the body utilizes vitamin B12 through the use of gamma cameras.

b. Calcium-47 for the study of bone metabolism

Calcium-47 is a radioactive isotope which releases beta rays. Since bones are mostly made of calcium, using Calcium-47 allows researchers to measure the rate of bone metabolism by monitoring the uptake and incorporation of this isotope into the bones. As calcium ions are an integral part of bone tissue, using a radioactive calcium isotope makes it easier to study how the bone is being built and broken down in the body.

c. Iron-59 for the study of red blood cell function

Iron-59 is a radioactive isotope that emits beta and gamma radiation. Iron is a major component of hemoglobin in red blood cells, which is responsible for transporting oxygen throughout the body. By using Iron-59 to label red blood cells, researchers can study the production, lifespan, and overall function of these cells. This can be helpful in diagnosing conditions such as anemia and other blood disorders.

d. Mercury-197 for brain scans before CAT scans became available

Mercury-197 is a radioactive isotope that emits gamma rays. It can be used as a radiotracer in the field of brain imaging when injected into the bloodstream. Due to its ability to cross the blood-brain barrier, Mercury-197 can be taken up by brain tissues, allowing doctors to visualize the structure and function of the brain before the introduction of other imaging techniques like CAT scans. Its use as a radiotracer in medical imaging was primarily due to its effective penetration into the brain tissue and the emission of gamma radiation that can be detected externally, providing valuable data about brain structure and activity.

Key concepts

Radioactive Isotopes

Radioactive isotopes, also known as radioisotopes, are atoms that have an unstable nucleus and emit radiation during their decay process. This unique property makes them valuable in various medical applications, especially in diagnosing and treating diseases.

• They can be naturally occurring or artificially produced in nuclear reactors or particle accelerators.
• The radiation emitted by isotopes can be alpha, beta, or gamma rays.
• The half-life of an isotope, which is the time taken for half of its atoms to decay, determines its suitability for different medical uses.

For instance, isotopes like Cobalt-57 and Iron-59 emit gamma rays, which are detectable using specialized imaging devices. This characteristic allows medical professionals to trace and visualize biological processes within the body. By choosing the appropriate isotope, doctors can study specific organs or functions without invasive procedures.

Medical Imaging

Medical imaging is a powerful tool in modern medicine, leveraging technology to observe the internal organs and tissues of the body without surgery. Radioactive isotopes are crucial to this field, providing valuable information through radiotracers.

• Gamma cameras can detect gamma radiation emitted by isotopes like Cobalt-57.
• Isotopes are introduced into the body and eventually build up in specific organs or tissues.
• The gamma rays emitted are captured to create detailed images of the internal structures.

Through imaging, doctors can detect health conditions, monitor the progress of diseases, and evaluate the effectiveness of treatments. For example, using isotopes such as Mercury-197, medical professionals were able to study brain activity when advanced imaging like CAT scans were not available.

Nuclear Medicine

Nuclear medicine integrates radioactive isotopes into various drugs, called radiopharmaceuticals, to diagnose and sometimes treat illnesses. Unlike other medical imaging methods, nuclear medicine emphasizes organ function rather than structure.

• Radiopharmaceuticals target specific organs or cellular receptors in the body.
• Upon decay, these isotopes emit radiation helpful in imaging or therapy.
• Conditions like thyroid disorders, cardiac diseases, and certain cancers often employ nuclear medicine techniques.

The aim is to glean information about several bodily functions effectively. For example, Cobalt-57 in radiolabeled Vitamin B12 helps assess how efficiently the body uses this vital nutrient, providing insight into absorption issues or deficiencies.

Bone Metabolism

Bone metabolism involves the continuous turnover of bone tissue through processes of bone formation and resorption. Investigating this activity can provide insights into several skeletal disorders.

• Calcium is a primary component in bones, making Calcium-47 a logical choice for studying bone metabolism.
• This isotope's beta radiation offers precise tracking of calcium uptake and use in the body.
• Such studies can reveal bone density issues or conditions like osteoporosis.

With Calcium-47, scientists can measure how bones incorporate calcium over time. Understanding these dynamics is crucial for diagnosing bone-related diseases and assessing the effectiveness of treatments aimed at strengthening bones.

Hemoglobin Function

Hemoglobin, a vital protein in red blood cells, is critical for transporting oxygen from the lungs to the rest of the body. The function and efficiency of hemoglobin can significantly influence overall health.

• Iron is an integral part of hemoglobin, allowing it to bind oxygen efficiently.
• Radioactive Iron-59 helps in studying hemoglobin production and red blood cell renewal.
• Such research aids in understanding conditions like anemia, where the oxygen-carrying capacity is compromised.

Using Isotopes like Iron-59 as tracers empowers researchers to track the lifecycle of red blood cells, ensuring that functional issues with hemoglobin are identified and appropriately managed, improving diagnostic precision and treatment.