Question

12. Compare and contrast how radioisotopes are used in medicine as diagnostic tracers versus for treatment purposes. Be as detailed as possible in your explanation. Include a description of the type of radiation emitted and the properties of the isotope that make it ideal for either a diagnostic or treatment application and describe how they work inside the body.

13. What are the biological microscopic and macroscopic effects of whole body, acute, high-dosage, ionizing radiation exposure on the human body? Describe what occurs within the cells. Which cell types are the most affected by acute radiation exposure? What are the macroscopic effects of damage to these cells? Be as detailed as possible in your answer.

Answer 1

12
Radioactive isotopes, or radioisotopes, are species of chemical elements that are produced through the natural decay of atoms. Exposure of radiation generally is considered harmful to the body but radioisotopes are valuable in medicine as diagnostic tracers versus for treatment perposes.

Nuclear pharmaceutical uses radioactive isotopes in many ways.One of the most common uses is as a tracer in which a radioisotopes, such as technetium-99m is taken orally or is injected into the body. Then radioisotopes circulate to the body or is taken up only by certain tissue.It's distribution can be tracked according to the radiation it gives off. The emitted radiation can be captured by many imaging techniques,like Singfle Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET),depending on the radioisotopes we are using.By such imaging physicians are able to examine the blood flow to the specific organs and organ fuction or bone growth.Radioisotopes are typically have short half-lives and decay before their emitted radioactivity can cause damage to the patient's body.

Therapeutic applications of radioisotopes are intended to destroy the targeted cells.This approach is the base if radiotherapy,which is used to treat cancer and other conditions involving abnormal tissue growth.In radiation therapy for cancer, the patient's tumor is bombarded with ionizing radiation, in the form of beams of subatomic particles,like protons,neutrons,alpha or beta particles,which directly disrupt the atomic or molecular structure of targeted tissue.

The use of radioisotopes in the field of nuclear medicine  and radiotherapy has advanced since the discovery of artificial radioisotopes.Artificial radioisotopes are produced from stable elements that are bombarded with neutrons.Following that discovery, researchers began to investigate potential medical applications of artificial radioisotopes, work that laid the foundation for nuclear medicine. Today diagnosic procedures using radioactive isotopes are very common.

13.
Ionizing radiation is a type of energy released by atoms that travels in the form of electromagnetic wave (gamma or X-ray)or particles(alpha or beta).The spontaneous disintegration of atom is called radioactivity, and excess energy emitted in the form of ionizing radiation. Unstable elements which disintegrate and emit ionizing radiation are called radionuclides.
All radionuclides are identified by the type of radiation they emit,the energy of the radiation and their half life.
Radiation exposure may be internal or external and can be acquired through many acquired pathways.
Internal exposure to ionizing radiation occurs when a radionuclide is inhaled.ingested or otherwise enters into the bloodstreams.Internal exposure stops when the radionuclide is eliminated from human body,either spontaneously or as a result of treatment.
External exposure may occur when airborne radioactive material (such as dust,liquid or aerosols)is deposited on skin or clothes.This type of radioactive material can often be removve from the body by simply washing.

Radiation damage to tissue or organs depends on the dose of radiation received or absorbed dose which is expressed in a unit called the gray(Gy).The potential damage from an absorbed dose depends on the type of radiation and the senstivity of different cells, tissues and organs.
The effect dose is used to measure ionizing radiation in terms of the potential for causing harm.The sievert(Sv)is the unit of effective dose that take into account the type of radiation and senstivity of tissue and organs.It is a way to measure ionizing radiation in terms of potential for causing harm. The Sv takes into account the type of radiation and senstivity of tissues and organs.
Beyond certain threshold, radiation can impair the functioning of tissues or organs and can produce acute effects such as skin redness,hair loss,radiation burns,or acute radiation syndrome.These effects are more severe at higher doses and higher dose rates.For instance, the dose threshold for acute radiation syndrome is about 1Sv.
Hematopoietic stem cell and cells of bone marrow that are rapidly dividing cells are most sensitive to the effects of ionizing radiation.

If the radiation dose is low or it is delivered for a long term ,the risk is substantially lower because there is greater likelihood of repairing the damage.There is still a risk of long-term effect such as cancer,however that may appears after years or even decades later.