Midterm Exam Flashcards
What is ALRA?
As low as reasonably achievable
Benefits must ______risks of any diagnostic study using ionizing radiation.
Outweigh
What are the 2 sources of ionizing radiation?
Natural and manmade
What are conditions necessary for x-ray production?
- Source of electrons
2.means for setting them in a high speed of motion (electricity)
- Mechanism for decelerating them abruptly (anode)
What is the cathode filament?
Milliamperage (mA) source of electrons.
What is potential difference during X-ray production?
KVP high speed motion
What is the target during x-ray production?
Anode (deceleration)
What type of tube is the X-ray tube?
Diode tube. Energy of the beam is expressed in kiloelectrons (keV)
What are the 5 ways x-rays interact with matter?
1.Classic scattering (Thompson)
2. Photoelectric interactions
3. Compton scattering
4. Pair production
5. Photodisintergration
What is classic coherent scatter?
X-rays with energy less than 10 keV. No energy transferred to patient or matter.
What are photoelectric interaction?
Within diagnostic x-ray range. Greatest hazard to patients.
What is Compton scatter?
Within diagnostic range. Most radiation exposure to workers.
What is pair production?
Nuclear medicine.
What is photodisintegration?
X-ray must be greater than 10 MeV. Common in nuclear industry.
What are the units of measurement in radiography?
Si units (international system of units)
1. Roentgen-in air
2. Gray- radiation absorbed dose (rad) radiation absorbed in any medium. 1Gy= 100 rad
3. Sievert- radiation equivalent man (rem)
4. Becquerel- curie. Measures activity if radioactive material. (Ci)
What is KERMA?
Kinetic energy released in matter.
What a radiation standards regulated by?
FDA. (CDRH) center for devices and radiological health.
What is the annual whole body effective dose limit for workers?
50 mSv (5 rem)
What is the whole body dose equivalent limit for the general population?
5 mSv (0.5 rem)
What are the cardinal rules of protection?
TIME. DISTANCE. SHIELDING.
What is the laws of Bergonie and Tribondeau!
Bergonie- cells are more radio sensitive during active cell division and when they are primitive in structure and function.
Trubondeau- cells are more radio resistant if they are more specialized in structure and function and do not undergo repeated mitosis.
What is indirect hit theory?
Involves irradiation of water and creation of free radicals.
What is direct hit theory?
Involves x-ray photon hitting DNA causing genetic damage.
What is acute radiation syndrome?
Total body response to high radiation exposure.
1.Prodromal stage. (NVD)
2. Latent period. No symptoms but biological change occurs.
3. Manifest stage. Full effects of radiation felt. Patient dies or gets better.
