Reproductive and gastrointestinal cells are not regenerating as quickly and are less sensitive. The nerve and muscle cells are the slowest to regenerate and are the least sensitive cells.
On the other hand, nerve tissues and muscle tissues, which no longer undergo cell division at the adult stage, are known to be resistant to radiation.
The most radiation-sensitive organs include the hematopoietic system [4], the gastrointestinal (GI) system [5], skin [6, 7], vascular system [8, 9], reproductive system, and brain [10–12].
The radiosensitivity of adenocarcinoma is generally lower than that of other types of epithelial tumors.
The digestive tract is among the most radiosensitive organs in the body and its function, which is partly regulated by gastrointestinal (GI) peptides, can be affected by radiation exposure.
Cells in late G2 and mitosis (M-phase) are the most sensitive to radiation, and cells in late synthesis (S-phase) are the most resistant (Fig. 23.10).
“These Langerhans cells were resistant to radiation.” The researchers also discovered that Langerhans cells are able to resist lethal doses of radiation because they express very high levels of an important protein involved in the stress response that orchestrates DNA repair after radiotherapy.
The central nervous system (CNS) is generally resistant to the effects of radiation, but higher doses, such as those related to radiation therapy, can cause both acute and long-term brain damage. The most important results is a decline in cognitive function that follows, in most cases, cerebral radionecrosis.
Ionizing radiation comes in three flavors: alpha particles, beta particles and gamma rays. Alpha particles are the least dangerous in terms of external exposure.
Blood cells have the highest turnover rate in our bodies, so the tissue where they are produced — the rapidly dividing cells of the bone marrow — is the most susceptible to radiation damage.
Ionizing radiation particles have in common the physical ability to generate free radicals that may cause direct or indirect DNA damage, but may also provide a source of metabolic stress to which the central nervous system (CNS) is particularly susceptible as compared to other tissue types2.
Critical Organs: Organs generally most susceptible to radiation damage include: Lymphocytes, bone marrow, gastro-intestinal, gonads, and other fast-growing cells.
Radiation causes acute or chronic injury in the liver. The early effects of irradiation include DNA damage, oxidative stress and reactive oxygen species production leading to hepatocellular apoptosis and acute inflammatory responses in irradiated regions.
Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation. In order from highest to lowest energy, the sections of the EM spectrum are named: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.
Measuring Radiation
The annual limit for radiation exposure for a member of the public is 1 mSv per annum or 1000 µSv per annum. If you are designated a radiation worker than you can receive up to twenty times this. I.e. 20 mSv per annum.
A type of radiation treatment called proton beam radiation therapy may be safer and just as effective as traditional radiation therapy for adults with advanced cancer.
As a result of these epidemiological studies, it was found that the mammary gland, skin, and colon, etc. are tissues and organs that are easily affected by radiation and develop cancer.
How Radioactive Contamination Is Spread. People who are externally contaminated with radioactive material can contaminate other people or surfaces that they touch. For example, people who have radioactive dust on their clothing may spread the radioactive dust when they sit in chairs or hug other people.
Gamma rays can be emitted from the nucleus of an atom during radioactive decay. They are able to travel tens of yards or more in air and can easily penetrate the human body. Shielding this very penetrating type of ionizing radiation requires thick, dense material such as several inches of lead or concrete.
Tardigrades represent a phylum of very small aquatic animals in which many species have evolved adaptations to survive under extreme environmental conditions, such as desiccation and freezing. Studies on several species have documented that tardigrades also belong to the most radiation-tolerant animals on Earth.
radiodurans, for example, can survive radiation levels that are over 1000 times higher than the levels that can kill human cells. The molecular basis of high-level resistance to ionizing radiation is not well understood, and several mechanisms have been proposed.
Distance: Just as the heat from a fire reduces as you move further away, the dose of radiation decreases dramatically as you increase your distance from the source. Shielding: Barriers of lead, concrete, or water provide protection from penetrating gamma rays.
A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The name "black body" is given because it absorbs all colors of light. A black body also emits black-body radiation.
Albert Stevens (1887–1966), also known as patient CAL-1 and most radioactive human ever, was a house painter from Ohio who was subjected to an involuntary human radiation experiment and survived the highest known accumulated radiation dose in any human.
Materials that block gamma radiation:
Lead aprons and blankets (high density materials or low density materials with increased thickness) Lead sheets, foils, plates, slabs, pipes, tubing, bricks, and glass. Lead-Polyethylene-Boron Composites. Lead sleeves.