Total Body Irradiation

Death

of course, is the most devastating human response to radiation exposure.

late effects of x-ray exposure

No cases of death after diagnostic x-ray exposure have ever been recorded, although some early x-ray pioneers died from the

total radiation dose

In each of these cases, however, the ____ was extremely high by today’s standards

Diagnostic x-ray beams

are neither intense nor large enough to cause death

ACUTE RADIATION SYNDROME

The sequence of events that follow high-level radiation exposure leading to death within days or weeks is called

Acute radiation-induced lethality

is of only academic interest in diagnostic radiology

diagnostic radiology

Acute radiation-induced lethality is of only academic interest in __

Acute Radiation Syndrome

Most notable deterministic health effect of ionizing exposure

deterministic

Acute Radiation Syndrome is a most notable ____ health effect of ionizing exposure.

Acute Radiation Syndrome

Sign and symptoms are not specific for radiation injury but collectively high characteristic for

inflammation

The main clinical sign

hypoplasia

The main structural feature

Acute Radiation Syndrome

Combination of symptoms occurring hours to week after exposure

Acute Radiation Syndrome

Combination of symptoms occurring hours to week after exposure

3

There are, in fact, ____ separate syndromes that are dose related and that follow a rather distinct course of clinical response

1. Hematologic death

2. Gastrointestinal (GI) death

3. Central nervous system (CNS) death

There are, in fact, 3 separate syndromes that are dose related and that follow a rather distinct course of clinical response, such as the:

Syndrome

It is the collection of signs and symptoms characterizing the response of an organism to radiation stimulus

Mean survival time

It is the average time between exposure and death.

LD 50/30

It is the lethal dose required to kill 50% of a population in 30 days

LD 50/60

It is the lethal dose required to kill 50% of a population in 60 days

250–300 rads

The LD50/60 in human is approximately

1. Prodromal Stage

2. Latent Stage

3. Manifest Illness Stage

4. Recovery or Death

In addition, to the three lethal syndromes, there are stages of response based on radiation dose level, such as the: (4)

Prodromal Stage

At radiation doses above 100 rad (1 Gy) delivered to the total body

Nausea

Vomiting

Diarrhea (N-V-D)

Leukopenia

The symptoms of early radiation sickness often take in the form of:

Prodromal Stage

may last from few hours to a couple of days.

Prodromal Stage

The severity of symptoms is dose related.

Prodromal Stage

At doses in excess of 1000 rad (10 Gy), symptoms can be violent.

dose related

The severity of Prodromal Stage symptoms is ____.

1000 rad (10 Gy)

Prodromal Stage At doses in excess of ____, symptoms can be violent.

still higher doses

At ____, the duration of prodromal syndrome becomes shorter, until it is difficult to separate from the period of manifest illness.

shorter

At still higher doses, the duration of prodromal syndrome becomes ___, until it is difficult to separate from the period of manifest illness.

manifest illness

At still higher doses, the duration of prodromal syndrome becomes shorter, until it is difficult to separate from the period of _____.

Latent Stage/Period

After the period of initial radiation sickness, a period of apparent well being occurs, which is called as the

Latent Stage

extends from hours or less(at doses in excess of 5000 rad) to weeks (at doses from 100 to 500 rad).

5000 rad

Latent Stage extends from hours or less(at doses in excess of ____ )

100 to 500 rad

Latent Stage extends from hours or less(at doses in excess of 5000 rad) to weeks (at doses from ____)

early recovery

moderate radiation dose

The latent period is sometimes mistakenly thought to indicate an ____ from a ____.

Latent Stage

The ____ is sometimes mistakenly thought to indicate an early recovery from a moderate radiation dose.

Manifest Illness Stage

After the latent stage, the animal becomes noticeably ill and shows signs and symptoms of the specific syndrome reflecting the organ system that is damaged

Manifest Illness Stage

It lasts from minutes to weeks depending on the dose

Death or Recovery

The animal either recovers or dies as a result of the damage sustained from the radiation exposure

Prodormal

Latent (Acute Radiation Syndrome)

Manifest Illness (Acute Radiation Syndrome)

Hematopoietic Syndrome

Also termed as hematologic, hematopoietic, or bone marrow syndrome

Hematopoietic Syndrome

Prodromal Stage

Nausea and Vomiting ✓ Bone marrow stems cells are dying ✓ Fewer mature cells being produced and lower numbers of cells in the circulating blood.

Hematopoietic Syndrome

Prodromal Stage

Hours after exposure

Hematopoietic Syndrome

Latent Stage

Few days to 3 weeks after exposure

Hematopoietic Syndrome

Manifest Illness

3-5 weeks post exposure

Hematopoietic Syndrome

Manifest Illness

Depression of all blood cell counts (cytopenia), which causes anemia and infections

Hematopoietic Syndrome

Recovery or Death

occurs between 100 and 1,000 R, with death occurring within 6-8 weeks in some individuals at a dose of 200 R

Recovery or Death (Hematopoietic Syndrome)

Death results from anemia and infection

Hematopoietic Syndrome

The LD50/60 for humans is estimated to be about 450 R or 250–300 rads, and is in the dose range of this syndrome

Gastrointestinal Syndrome

Appears in all animals at doses between 1,000 and 10,000 R.

600 R

Gastrointestinal Syndrome in humans, symptoms appear at a threshold dose of

1,000 R

Gastrointestinal Syndrome in humans, symptoms appear at a threshold dose of ith the full syndrome manifest at

Gastrointestinal Syndrome

In humans, symptoms appear at a threshold dose of 600 R, with the full syndrome manifest at 1,000 R

Gastrointestinal Syndrome

Occurs because of damage to the GI tract and bone marrow

Gastrointestinal Syndrome

he GI tract lining, especially the small intestine, is damaged by doses in this range

Gastrointestinal Syndrome

The mean survival time remains relatively constant, at 4 days

4 days

Gastrointestinal Syndrome mean survival time remains relatively constant, at

Central nervous system Syndrome

It occurs at doses greater than 5,000 R in humans

5,000 R

Central nervous system Syndrome occurs at doses greater than ____ in humans

CNS syndrome

Death caused by the ___ is not fully understood.

CNS damage

may result from damage to the blood vessels that supply the system,

• edema (swelling) in the cranial vault

• vasculitis (inflammation of blood vessels)

• meningitis (inflammation of the spinal cord and brain membranes)

CNS damage may result from damage to the blood vessels that supply the system, thus causing:

Gastrointestinal Syndrome

Prodromal Stage

Hours after exposure

involves nausea and vomiting, cramps, and diarrhea

Gastrointestinal Syndrome

Latent Stage

Occurs through the 15th day.

Gastrointestinal Syndrome

Manifest Illness

Perseveres from the 5th through the 10th days.

Gastrointestinal Syndrome

Manifest Illness

Perseveres from the 5th through the 10th days.

Gastrointestinal Syndrome

Recovery or Death

3 days to 2 weeks

Gastrointestinal Syndrome

Recovery or Death

Death results from infection, dehydration, and electrolyte imbalance

Central nervous system Syndrome

Prodromal Stage

Depending on the dose, lasts from a few minutes to a few hours

Central nervous system Syndrome

Prodromal Stage

✓ nervousness ✓ confusion ✓ nausea and vomiting ✓ loss of consciousness ✓ burning sensations of the skin

Central nervous system Syndrome

Latent Stage

-May last several hours

Central nervous system Syndrome

Manifest Illness

Occurs 5-6 hours after exposure

Central nervous system Syndrome

Manifest Illness

✓ Diarrhea ✓ Convulsions ✓ Coma ✓ Death

Central nervous system Syndrome

Recovery or Death

Within 2 days

Central nervous system Syndrome

he mean survival time is again dose dependent, varying from approximately 3 days to a matter of hours

3 days

Central nervous system Syndrome the mean survival time is again dose dependent, varying from approximately

organs

The sensitivity to radiation of different organs and their consequences for the individual person vary very much between

a. the fraction of the organ irradiated (the volume effect)

b. the overall exposure time (the time factor)

c. the dose rate or dose per fraction (the fractionation effect)

Influencing factors on radiation sensitivity depends on: