Question

a. Technetium- \(99 \mathrm{~m}\) emits only gamma radiation. Why would this type of radiation be used in diagnostic imaging rather than an isotope that also emits beta or alpha radiation? b. A person with polycythemia vera (excess production of red blood cells) receives radioactive phosphorus-32. Why would this treatment reduce the production of red blood cells in the bone marrow of the patient?

Short answer

a. Gamma radiation provides clear images with minimal tissue damage, ideal for diagnostic imaging.b. Phosphorus-32 targets and inhibits rapidly dividing cells in the bone marrow, thus reducing red blood cell production.

Step-by-step solution

Understanding Gamma Radiation

Gamma radiation is a type of electromagnetic radiation. It is highly penetrating and can pass through the human body, making it suitable for diagnostic imaging as it can create clear images without damaging tissues.

Analyzing Beta and Alpha Radiation

Beta and alpha radiation have higher mass and charge than gamma radiation. They are more likely to interact with and damage tissues, which is not desirable in diagnostic imaging as it can be harmful to patients.

Conclusion for Part (a)

Gamma radiation is used in diagnostic imaging because it can pass through the body with minimal interaction, reducing potential harm while providing clear images.

Explanation of Polycythemia Vera

Polycythemia vera is a condition characterized by the excessive production of red blood cells, which thickens the blood and can lead to complications.

Impact of Radioactive Phosphorus-32

Phosphorus-32 is a beta emitter. When introduced into the body, it is taken up by rapidly dividing cells such as those in the bone marrow. The beta radiation specifically targets these cells and inhibits their growth.

Conclusion for Part (b)

Treating with phosphorus-32 reduces the production of red blood cells by killing or slowing down the growth of bone marrow cells responsible for their production.

Key concepts

Gamma Radiation in Diagnostic Imaging

Gamma radiation is a type of high-energy electromagnetic radiation. It has a very high penetration power, which means it can travel through the human body without much absorption. This property makes gamma radiation ideal for diagnostic imaging because:

• It provides clear and precise images of the internal structures of the body.
• It minimizes harm to tissues and organs due to its minimal interaction with the body.

Technetium-99m, which emits only gamma radiation, is commonly used in nuclear medicine because it allows doctors to obtain detailed images without causing significant damage to the body's cells.

Beta Radiation

Beta radiation consists of high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei. Unlike gamma radiation, beta particles have mass and charge. This makes them more likely to interact with and damage bodily tissues. As a result:

• Beta radiation is typically not used in diagnostic imaging. It could cause harm to cells and tissues, leading to potential health risks.
• However, beta radiation is useful in certain treatments where targeted destruction of cells is needed.

For example, in the treatment of polycythemia vera, beta radiation can be particularly effective.

Radioisotope Therapy

Radioisotope therapy utilizes radioactive substances to treat various medical conditions. In this therapy:

• Specific radioisotopes are chosen based on their radiation type and energy, ensuring they target and destroy diseased or abnormal cells efficiently.
• It can be used for treating cancers and other diseases where targeted cell destruction is necessary.

For instance, beta-emitting isotopes like phosphorus-32 are used to treat conditions like polycythemia vera due to their ability to damage and inhibit the growth of rapidly dividing cells such as those found in bone marrow.

Polycythemia Vera Treatment

Polycythemia vera is a rare condition characterized by an overproduction of red blood cells. This makes the blood thicker and can lead to serious complications. Treatment approaches include:

• Radioactive phosphorus-32, a beta emitter, which targets bone marrow cells where red blood cells are produced.
• Beta radiation from phosphorus-32 inhibits the overactive bone marrow cells, reducing red blood cell production effectively.

By addressing the root cause of the excessive red blood cell production, phosphorus-32 therapy helps in managing polycythemia vera.

Phosphorus-32

Phosphorus-32 is a radioactive isotope commonly used in medical treatments. It is a beta emitter, meaning it releases beta radiation, which has specific medical applications:

• It is absorbed by rapidly dividing cells, such as those in the bone marrow.
• It inhibits the growth of these cells by damaging their DNA or cellular structures.

This characteristic makes phosphorus-32 effective in treating conditions like polycythemia vera, where it targets the overproducing red blood cell precursors in the bone marrow, thereby helping to control the disease.