Radiation - Quiz 5 Flashcards
What is Conduction heat exchange?
Heat transfer thru physical contact
What is Convection Heat Exchange?
Heat transfer via movement of matter
EX: Hand over flame
What is Radiation Heat Exchange?
Heat transfer involving Electromagnetic Waves
How are Electromagnetic waves produced?
Acceleration of Charged Particles
Wave-Like & Particle-Like Properties
Electromagnetic waves also act like small packets of energy, also known as?
Photons
According to Energy Conservation, How does the Total energy in an Isolated System change?
Total Energy is the kinetic energy & the mass equivalent - total energy remains constant
What is Radioactive Decay?
Spontaneous process where an unstable nucleas goes from high energy to low energy
Happens when repulsive forces > attractive forces
What is a Radionuclide?
A nuclide that undergoes Radioactive Decay
What determines the Electromagnetic Radiation’s effect on Matter?
Energy of the Photon(s)
What is Non-Ionizing Radiation?
When photons dont have enough energy to ionize matter and the energy just gets absorbed by matter, causing an increase of internal energy
EX: Microwave, Infrared, UV Radiation, Visible LIght
What is actually happening when matter is exposed to Non-Ionizing Radiation and the energy is absorbed?
Rotation, Vibration, or Excitation of Electrons inside the molecule or atoms
What does Microwaves do to Atoms & Molecules?
Atoms: Nothing
Molecules: Rotation
What does Infrared do to Atoms & Molecules?
Atoms: Nothing
Molecules: Rotation & Vibration
What does Visible Light & UV Light do to Atoms & Molecules?
Rearrange electrons for both
Why is Ionizing Radiation more Dangerous than Non-Ionizing Radiation?
Ionizing Radiation has enough energy to Break Chemical Bonds
EX: X-rays, Gamma Rays, Alpha/Beta Particles
What are the 3 Sources of Radioactive Material?
Primordial - exists from beginning of time
Cosmogenic - Radiation from space
Anthropogenic - From environment d/t human activities
What is the Unit in which radiation Exposure is measured?
Roentgen (R)
What is the Absorbed Dose of Radiation?
Amt of radiation energy absorbed per unit mass
(rad: radiation-absorbed dose is an older unit used)
At the most basic level, what does Ionizing Radiation do to Atoms & Molecules?
Removes Electrons from Atoms & Molecules
What type of cells are highly sensitive to radiation?
Cells that divide frequently - bone marrow, embryos, male gonads, tumors, CNS
What is the term for Bioligical Effects due to Radiation Exposure?
Somatic
What are the products made when Radiation interacts with the water in our cells?
Ions, Free Radicals, and Excited atoms/molecules that can indirectly lead to DNA damage
Ionizing Radiation can directly lead to DNA damage
What is the term used for effects or mutations from Radiation Exposure passed on to future generations?
Genetic Effects
What are Tissue Weighting Factors (WT)?
Way to determine various radiation sensitivity of different tissue & organs
What is the Tissue Weighting Factor for Gonads?
WT = 0.20
What is the Tissue Weighting Factor for Bone Marrow & Lung?
WT = 0.12
What is the Tissue Weighting Factor for Bladder, Breast, Liver and Thyroid?
WT = 0.05
What is the Tissue Weighting Factor for Skin?
WT = 0.01
What is the ALARA Principle?
_A_s _L_ow _A_s _R_easonably _A_chievable
What do Dosimeters, film badges, and finger rings do?
Monitors Occupation Dose of Ionizing Radiation exposure
What are three ways to enforce the ALARA principle?
Time
Distance
Shielding
What is the Inverse Square Law?
Dose is Proportional to the Inverse of the Square of the Radius
Double the distance = reduces 4x the radiation
What is the basic concept of Waves?
Periodic ripples, disturbances, or movement of energy
What are the types of Waves?
-
Transverse Waves - moves up and down (perpendicular)
- EX: Electromagnetic Waves
-
Longitudinal Waves - moves back and forth (parallel) and causes compression & decompression (Rarefaction)
- Sound waves
What is Wave Frequency?
Waves/Cycles per second measured in Hertz (Hz)
What is Wavelength?
Distance from one wave crest to the next
How far the wave “slides” is also known as its?
Period or Phase Shift
What is the Wave Amplitude?
Height of the wave
What unit is the Speed of the Wave measured?
Meters per Second
What is the bottom of the Wave called?
Trough
What kind of waves can be Refracted, Diffracted or Absorbed by other waves?
Pressure Waves (Sound Waves)
What is Wave Reflection?
Waves reflect off a medium at same, but opposite angle
What is Wave Refraction?
Redirection of a wave due to contact w/ a new medium
What is Wave Diffraction?
Wave Spreading, Scattering, or Bending around an object
What happens when Sound Waves interact with certain tissues that cause Attenuation (reduction of amplitude/effect)?
Wave is converted to Heat and Dissipates
What are the Signal Generators & Signal Transducers of Ultrasonography?
Piezoelectric Crystals
What is the Resonant Frequency regarding Piezoelectric Crystals?
The rate of vibration & pressure fluctuation
Considered a Pressure Wave
What is the Doppler Effect?
Describes change in frequency of a wave from a moving object
Wave frequency decreases as object moves further away and increases when object gets closer d/t stacking of waves
How is the Doppler effect useful clinically?
Can determine blood flow direction & speed
What is Magnatism?
Force b/t electric currents where the charges are aligned in orderly fashion and can disrupt and alter the surrounding environment
How does an MRI work?
- Strong continuous magnetic field realigns the spin of protons and delivers a radiofrequency pulse to energize the protons
- Protons will emit this energy
Which MRI Safety Zone poses the greatest risk of Injury?
Zone 4 - immediate area around scanner
What are the safety guidelines in Zone 4 of the MRI?
Ferrous materials must be removed before entering
Special Equipment only
Implanted devices are OK
