Protection radiation ( intro to mdi) Flashcards
What is the unit and Sl unit Exposure in air ?
Unit Roentgen and SL unit C/Kg
What is absorbed dose ? and the unit ?
Is the amount of energy absorbed in any medium ( it is for patient)
SL unit : Gray / unit : absorbed dose (rad)
1gy = 100 rad
Dose equivalent ?
For the worker and population
Traditional unit : beta, gamma and alpha ( Rem)
Sl unit : Seivert
Sv = 100 rem
Radiation activity
Traditional unit : Curie
Unit : Bq
1ci = 3.7 x 10^10 Bq
what is AlARA ?
As low As Reasonably Achievable
Has principles : Time / distance and shielding
Time ?
Reduces the time of an exposure which reduces the dose
minimize the time that you are contact with radioactive materials
Distance ?
increasing distance reduces dose due inverse square law
increases the distance decreases the dose
the closer you are the source the greater your exposure will be
Shielding ?
Are made of lead which absorbs x ray
gonads over reproductive organ ( lead aprons)
what is the purpose of protective apparel ?
It must used when the x ray beam is turned on
Min = 0.5 mm pb when beam energy is100kvp
Radiation effect ?
direct effect : Deposited directly to ( DNA)
results in cell death
Indirect effect : Deposited cytoplasmic ( water)
May exist long enough to affect DNA
what are stem cells and mature cells ?
Stem cells are radiosensitive ( organs)
Mature cells are radioresistant
Biological factors of radiosensitivity ?
Age , gender , metabolic rate and oxygen effect
Principle’s of radiosensitivity ?
Growth rate
Immature cells
Rapidly dividing cells
Others factors affect radiosensitivity ?
LET : ( linear energy transfer )
RBE : ( Relative biological effectiveness)
what is LET and RBE ?
How ionizing energy is deposited in tissue
Is the ratio of the dose required by 2 radiations to cause the same level of biologic effect
The highest factor affect radiosensitivity in the graph ?
Heavy nuclei
then alpha particles
What are the biological effects of radiation ?
1) How the responses ( symptoms)
2) Relate to dose ( amount of dose received )
2 types : Stochastic Effects
Deterministic Effects
what is stochastic effect ?
Have an increased probability of occurrence with increased dose
Non- threshold response , linear dose response
ex : sunlight , skin cancer
Depends on radiation dose
long period
what is deterministic effects ?
Are those responses which increase in severity with increased dose
Threshold dose response , non linear dose response
high doses , depend on dose
It can cause fetal damage , skin injury
Acute radiation syndrome ?
Is the high dose of radiation effects
syndromes : Hematologic / Gastrointestinal / CNS
Stages of acute radiation ?
Prodromal : It shows the signs and symptoms resulting from radiation exposure to the whole body within hours ( last up day or two)
Latent : If there is no visible symptoms, there may be ongoing cell damage
Manifest : Effects are evident
Death : The survival depends on complex factors (amount and distribution of the radiation)
What are the Doses of Hemopoietic , Intestinal and brain ?
The dose = 300 , Latency = 2 weeks and death = 3 weeks
The dose = 1000 , Latency = 3 days and death = 2 weeks
The dose = 2000 , Latency= 1 hour and death = 1 day
What are the somatic effects ?
Gonadal effects : Sterility
Erythema : Skin reddening ( 6Gy)
Epilation : temporary hair loss ( 3 Gy)
Cataracts : Opacity ( 2Gy)
Effects of Carcinogenesis ?
Fetal effects ( prenatal and neonatal death)
Genetic effects : Doubling dose / Significant dose
