rads 2060 radiation biology the history of radiobology chapter 1

Science dealing with interaction and effects of ionizing radiation on living systems.

What is Radiobiology?

Determined that exposure to human uterine cervix cells causes reproductive failure.

Puck and Marcus

All cells are equally susceptible to damage by radiation, but only if and when the cell divides will the damage be demonstrated.

Ancel and Vitemberger

radiation produces the same mutations that are normally produced in nature, but the frequency of mutations is intensified by exposure to radiation, mutagenesis.

Herman Muller

The presence of oxygen increases the killing of cells when wxposed to radiation.

Charles Rick

If an original dose of radiation is broken into smaller doses, spread over a period of time, there is less radiation damage, fractionation.

Claude Regaud

Actively mitotic and undifferentiated cells are most susceptible to damage from ionizing radiation. A fetus is more radiosensitive than a child or adult.

Bergonie and Tribondeau

Cells have the ability to recover from small radiation doses

Elkind and Sutton-Gilbert

A measure of ionization in air

2.58 x 10-4th coulomb/kg air

roentgen

a description of energy that is absorbed in matter from any type of ionizing radiation

100 ergs/gram of absorbing material

Rad

Unit of dose equivalent or occupational exposure

same biological effectiveness of 1 rad of xray

rem

Frequent exposure is ______ of limit for rad workers,

____ rem per year.

1/50, .01

Infrequent exposure is ______ of limit for rad workers. Example, a patient in the waiting room, _____ rem per year

1/10, .5

NRC _______ set dose equivalent limits based on ______ report #91-Limits occupational exposure to 5 rem per year and 0.1 rem for frequent exposure per year for the public-Public is allowed 0.5 rem annually for infrequent exposure

1994, NCRP

__________ set annual occupational exposure limit of 5 rem per year and dose limit for public of 500 mrem (0.5 rem) per year

ICRP 1977

Annual occupational effective dose limit

50 mSv (5 rem)

1 Gray = ? Rad

100

1 Rad = ____ Gy

0.01

1 rem = _____ Sv

0.01

1 Sv = ___ rem

100 rem

Radiation Equivalent Man

REM

Rem has the same approximate biologic effectiveness as ________ of x-ray

1 rad

Measure of ionization of air created by x- and gamma radiation below _______

3 MeV

Ionizing indirect effect

Ionization makes free radical. Free radical causes DNA damage.

____________, original ionization occurs directly on a target molecule

direct effect

_________, original ionization occurs with water and transfers ionization to a target molecule (formation of free radicals)

indirect effect