Effects of Radiation Exposure

What is the fifth most radiosensitive cell?

Endothelial cells

What is the fourth most radiosensitive cell?

Epithelial Cells

What is the earliest possible observable symptom of radiation exposure?

Erythema

_____ amount of exposure to radiation has a biological effect.

Any

Short term effects

Appear quickly, within minutes, days or weeks.

Long term effects

Appear years, decades, or generations later.

ALARA

As Low As Reasonably Achievable

What is the seventh most radiosensitive cell?

Bone cells

What is the ninth most radiosensitive cell?

Brain cells

What happens during radiation injury?

Cell recovery involves enzymatic repair of DNA, Greater recovery of short-term effects, Some damage is irreparable

What is the sixth most radiosensitive cell?

Connective tissue cells

What are the results of direct effect?

Depends upon quantity and duration of exposure.

Threshold dose

Dose below which there is no response

What is the third most radiosensitive cell?

Immature reproductive cells

What are the effects of long term radiation exposure?

Increases incidence of cancer Embryonic defects Cataracts Lifespan shortening Genetic mutations

Latent period

Lag time between initial exposure and the first detectable effect occurs

The ______ the area the greater the injury is to the organism when xraying.

Larger

What are the radiosensitive structure of the head and neck?

Lens of eye, mandible, thryoid gland

Recovery

Most cells repair minor damage that might occur. Only in cases where exposure is massive is an entire body destroyed.

What is the least radiosensitive cell?

Muscle cells

What are the sign and symptoms of Acute Radiation Syndrome?

Nausea, Vomiting, Diarrhea, Hemorrhage, Hair Loss

What is the eighth most radiosensitive cell?

Nerve cells

What are the causes of long term effects by radiation exposure?

Previous acute exposure from which the patient has recovered, Chronic low-level exposures delivered over many years.

Law of B and T

Radiosensitivity directly proportional to reproductive capacity. Radiosensitivity inversely proportional to degree of differentiation.

What is the second most radiosensitive cell?

Red Blood cells (erythrocytes)

Radioresistant

Refers to a substance or tissue that is not easily injured by ionizing radiation.

Radiosensitive

Refers to a substance or tissue that is relatively susceptible to injury by ionizing radiation.

What happens during radiation injury?

Stoppage of mitosis or cell division (mitotic delay) which may be temporary or permanent Breaking or clumping of chromosomes Abnormal mitosis Formation of giant cells

Genetic cells

The cells contained within the testes and ovaries, containing the genes.

Total Dose

Type, energy and duration of radiation. Greater the does the more severe the biological effect.

The most radiosensitive cell is?

White blood cells (lymphocytes)

There is a _______ variation in sensitivity between different species and different individuals within the same species.

Wide

How does age effect radiation injury?

Younger cells divide more rapidly;therefore, are more radiosensitive- children are more susceptible than adults. Older people can't repair as quickly though

What are the steps of indirect effects (indirect-action, poison water theory)?

a. Ionization of water b. water converted to hydrogen and hydroxyl free radicals c. if molecular oxygen is present, hydrogen peroxide may be formed and acts as a poison.

What are the steps of direct effect (direct hit)?

a. X-ray photons will collide with cell chemicals b. large molecules are broken apart c. critical damage caused by breakage

Acute Radiation Syndrome

acute whole body exposure (high dose in short period of time) Dose over 1.0 gray or 100 rads - whole body Dental x-ray machine can not produce large enough exposure to cause ARS

Somatic Cells

all the cells of your body except your sex cells

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Linear nonthreshold

it is assumes that any does causes some response

Cells recover if damage isn't too severe; however they do not completely return to the ________ state.

preirradiated

Dose Rate

rate at which radiation is administered. Greater recovery will occur if time is given between doses.

Ionization

x-rays ability to alter the delicate balance of cell structure which can damage or destroy cells