Chapter 9: Basic Radiation Protection and Radiobiology Flashcards
Who discovered X-rays?
Wilhelm Rongten
When were X-rays discovered?
November 8th, 1895
What was the name of Rongten’s report?
On a New Kind of Rays
Name the 3 common natural sources of ionizing radiation.
Radium, Uranium, and Cosmic Rays
Name sources of man made ionizing radiation.
Nuclear, Radionuclides, and Diagnostic Xrays
What does Roentgen measure?
exposure in the air, below 3MeV
What does RAD stand for?
Radiation Absorbed Dose
What do RAD’s measure?
amount of radiation a person/body part absorbs as xrays pass through body.
What does REM stand for?
Radiation Equivalent Man (Gy is the SI unit) 1 Gy=100 rad
What does REM measure?
The biological response. (Sv is the SI unit) 1 Sv= 100 rem
Curie (Ci) measures what?
measures rate of radionuclide decay (Bq is the SI unit) 1 Ci= 3.7x10^10 Bq
What is the speed Xrays travel?
They travel at the speed of light!
A “bundle of energy,” or group of photons is called what?
Quantum
What 3 things must be present to create xrays?
Cathode (containing a filament made of thoriated tungsten), A current to move electrions (mAs), and an Anode which stops them rapidly from positive charge.
What is thermionic emission?
When the filament in the cathode heats up and emits electrons.
When electrons strike anode, what is produced?
99% heat and 1% xrays.
Name 3 types of scattering.
Classic Coherent, Photoelectric Effect, and Compton Scattering.
Explain Classic Coherent.
An incoming xray photon strikes atom and is absorbed which excites atom, releasing another photon with SAME energy. No energy transfer to patient.
Explain Photoelectric Effect.
Xray photon strikes INNER SHELL ELECTRON, creating ion pair. Energy is completely consumed causing greatest hazard to patient.
Explain Compton scattering.
Incoming xray photon strikes OUTER SHELL ELECTRON, which deflects in another direction (scatter). Most occupational exposure happens here.
CDRH stands for….
Center of Devices and Radiologic Health
NCRP stands for…
National Council on Radiation Protection and Measurement.
MPD stands for…
Max Permissible Dose, which no longer is in use.
ADL stands for…
Affective Dose Limit, which is now in use because there is always a chance of biological effect.
Dose Limits
Occupational worker: 50 mSv (5 rem) annually.
Public: 1/10 of worker so 5 mSv (.5 rem) annually.
To get Occ workers whole body dose: 10 mSv x age of worker.
What is the difference between somatic cells and germ cells?
Somatic cells: (regular function 46 chromosomes divide through mitosis) Germ cells: reproductive cells 23 chromosomes reproduce through meiosis.
Direct Hit Theory is when…
radiation hits DNA which can re-arrange genetic info.
Indirect Hit Theory is when…
radiation hits cytoplasm, causing: ion pairs, excited state, chemical change. *This one is more likely to occur.
Bergonie and Tribondeau (B&T) theory says what?
Cells are most sensitive to radiation during active division, therefore cells that undergo division often are more sensitive.
What are the 4 examples of radiosensitive cells?
Ball cells, Crypt cells, Germ cells, and Blood cells.
Which cells do not undergo repeated mitosis and are therefore resistant to radiation?
Never cells, Muscle cells, and Brain cells.
3 acute radiation syndromes:
Bone marrow: occur at doses 2-10 Gy leading to infection, hemorrhage, and anemia.
Gastrointestinal: doses 10-50 Gy leading to DNV
CNS: doses above 50 Gy leading to convulsions, coma, and eventually death.
3 stages of acute radiation syndrome:
Prodromal: NVD
Latent: feeling of well-being.
Manifest: feeling full effect of exposure.. either leads to curing, or death.
Late Effects:
Somatic effect: cataracts, cancer
Genetic effect: future generations affected
Dose limits for pregnant tech:
Per month: .05 rem (.5mSv)
For entire pregnancy: .5 rem (5mSv)
*wear fetal badge
OSL badge stands for…
Optically Stimulated Luminescence Dosimeter (reads between 1 mRem to 1000 rem)
Film badges detect doses below…
10 mRem
TLD…
thermo-luminescent dosmiter
Pocket Dosimeters
have a metal electrode that’s positively charged, exposing it to radiation neutralizes electrode. Immediate reading is available.
