Chapter 33

What do gonads & ovaries produce ?

- Germ cells that control fertility & heredity

What is Acute Radiation Syndrome ?

- High-level radiation exposure leading to death with-in days or weeks

How many days do thrombocytes have in bone marrow ?

- Lifetime aprrox. 5 days

What dose relationship is single-hit aberrations ?

- Linear, nonthreshold

What is kinetiucs of chromosome aberrations ?

- Low dose radiation, only single hit aberrations occur

What is the 1st cell to take a dive after radiation ?

- Lymphocytes b/c they reduce # with in minutes or hours after exposure (Direct hit)

What is the most significant latent human damage ?

- Multihit aberration

What is reciprocal translocation ?

- Multihit chromosome aberrations that require karyotypic analysis for detection

What dose relationship is multihit aberrations?

- Non-linear, nonthreshold

What cell is most radio sensitive in ovaries ?

- Oocyte, Mature-follicle

What is the stem cell of ovaries ?

- Oogonia

2 Periods associated with acute radiation lethality

- Prodromal period - Latent period

What is early effect radiation ?

- Produce radiation response in humans w/in a few days to months - Rare in diagnostic radiology

What is radiation induced reciprocal translation ?

- Results in no loss of genetic material simply a rearrangement of the genes

What is Grenz x-rays ?

- Soft x-rays 10-20 kVp to treat ring worms (tinea capitis)

What are the stem cells of the testes?

- Spermatogonia: Radiosensitive

What is the deterministic radiation effect ?

- Those that exhibit increasing severity w/ increasing radiation dose ★ Diagnostic x-ray beams are neither intense enough nor large enough to cause death ★ Diagnostic x-ray beams always result in partial body exposure, which is less harmful than whole body experience

What is desqumation ?

- Ulceration & denudation of skin followed by erythema

What are the three separate acute radiation syndromes related ?

1. Hematologic Death 2. GI tract 3. CNS death (requires excess 50 Gyt= death w/in hrs)

Minimal Detectable response is approx what dose?

100 mgyt

What is the threshold on deterministic effects ?

2 Gy

After 100 mGyt is exceeded the male patients should refrain from procreating ?

2-4 months

Temporary infertility caused by radiation dose of

2000 mgyt

sterility caused by how much dose?

5000 mgyt

CNS

>50 0-3 Same as GI tract + ataxia, edema, system vasculitis, meningitis

Cytogenetics is the study of the?

Genetics of cells, particularly cell chromosomes;

Prodromal period

Rapid onset, immediate response of radiation sickness a. Severity of symptoms is dose related: excess of 10 Gyt violent symptoms

What is mean survival time ?

Whole body radiation dose increases, the average time between exposure & death decreases

What creature handles the most radiation ?

cockroach

The ultimate cause of death in CNS syndrom is

elvated fluid content of the brain

What are the most radiosensitive cells in the body?

lymphocytes and the spermatogonia

What is karotype ?

map of chromosomes; shows the sex and defects

Radiation-induced death in humans follows a what kind of dose relationship?

non-linear, treshold dose response

Radiation-induced chromosomes aberrations follow a what king of relationship?

non-treshold dose response

Damage to the basal cells results in

the earliest manifestation of radiation injury to the skin.

Latent period:

time after radiation exposure during which there is no sign of radiation sickness (Dose related)

What is moist desqumation ?

- Clinical tolerance for radiation oncology

What is the principal response to blood when radiation exposure is give ?

- Decreases in the number of all types of blood cell in the peripheral blood

What are the effects on the hematic hemolotogic system are going to be observed ?

- Depressed # of blood cells in peripheral circulation

What is the most approx way to measure dose ?

- Doseometer (Flim, TLD, ODL)

GI Tract

- 10-50 - 4-10 Same as hematologic + electrolyte imbalance, lethargy, fatigue, shock

At what dose produces temporary infertility for both male & female?

- 2 Gyt or 2,000 mGyt causing 2-12 of temporary infertility

What can cause the skin erythma by a single exposure?

- 3-10 Gyt in the 1st-2nd day

When do stem cells turn over?

- 3-5 days - But radiation exposure kills the stem cells

At what dose produces permanent sterility for both male & female ?

- 5 Gyt or 5,000 mGyt

What is the dose for SED ?

- 5 Gyt required to affect 50% - When threshold dose has been exceeded the severity of the response increases w/ increase dose in a non0linear fashion

What is the record limit of dose someone survived?

- 8.5 Gyt or 850 RADS

What is an early response to radiation exposure ?

- All cells can sustain cytogeneic damage - If cell survives damage is manifested during the next mitosis

What is pluripotential stem cells ?

- All hemopoietic cells develop into several different types of mature cells

At what exposure level would you be expected to die from whole body dose ?

- Anything above 200 RAD/ 2 Gyt

At what rate are skin cells replaced?

- Approx. 2%

How often to we replace intestinal cells ?

- Approx. 50% everyday

At what dose does female menstruation delay/supress & in male reduces spermatozoa?

- As low as 100 mGyt

What is the lowest layer of your epidermis ?

- Basal cell which are stem cells

What is a great exapmle of genetic defect ?

- BrCa1 & BrCa2 located on chromosomes 17 & 13

What is breakage of the chromatid is called ?

Chromatid deletion

What cells do we use for cytogenetic analysis ?

Lymphocytes

How many days do they spend in peripheral blood ? Lyphocytes: ? Granulocytes: ? Thrombocytes: ? Erythrocytes: ?

Lyphocytes: lifetime varies Granulocytes: lifetime of couple days Thrombocytes: Approx. 1 week Erythrocytes: nearly 4 months

With a chromosome hit can you tell the difference if it was direct or indirect ?

No

Cells in the bone marrow proliferate in #, differentiate in fnx/mature, developing in granulocytes & erthrocytes about 8-10 days in bone marrow. True or False

True

Each cell has 22 pairs of autosomes & 1 pair of sex chromosomes: the female X chromsome & Male Y chromosomes. TRue or False

True

Some laboratories use cytogenetic analysis as a biologic radiation dosimeter. True or False

True

Under no circumstances is a periodic blood examination recommended as a feature of any current radiation protection program. True or False

True

★ A chromosome hit represents severe damage to the DNA. True or false

True

★ From single pluripotentional stem cell, a number of cell types produced. True or False

True

★ Male gametogenesis is a self- renewing system. True or False

True

★ Skin follows a non-linear threshold dose response relationship. True or false

True

Is it possible for a single chromosome to receive more than 1 hit?

YES

Is employment in the nuclear power industry safe ?

Yes!

Means survival time is dose related.

a. Lower the dose = longer the latent period b. Higher the dose = latent period shrinks

When can chromosome aberrations appear in your blood cells after exposure ?

anytime

Hematologic

approx dose. 2-10 mean survival 10-60 Nausea, vomiting, diarrhea, anemia, leukopenia, hemorrhage, fever, infection

IR and Cath lab are high dose

fluroscopy

When you get above 1 Gyt, what happens to the frequency of multihit aberrations ?

increases

what is e LD 50/60?

is the whole body radiation dose that causes 50% of irradiated subjects to die with-in 60 days @ 3.5 Gyt/350 RADs

Acute radiation lethality follows which dose relationship?

nonlinear, threshold dose relationship

Ovaries & testes produce

oogonia & speratogonia, which mature into ovum & sperm, respectively

The hematologic syndrome is characterized by a

reduction in white blood cells, red blood cells, and platelets

GI death occurs principally because of...?

severe damage to the cells lining the intestines

SED stands for

skin erythema dose