| A | B |
|---|
| What is the definition of radiation as given in the notes? | Energy in motion through space and matter |
| What are the spectrum order sources of radiation? | Radio Waves, Microwaves, Infrared, Visible light, Ultraviolet light, X-Rays and Gamma Rays |
| What is the non-spectrum order sources of radiation? | Protons, Neutrons, Electrons, Beta Particles and Alpha particles |
| Non-ionizing radiation | lacks the energy to knock an electron out of orbit |
| 5 examples of non-ionizing radiation | Radio waves, microwaves, infrared, visible light and ultraviolet light |
| Ionizing radiation | Has the energy to knock an electron out of orbit |
| 7 examples of Ionizing radiation | X-rays, gamma rays, protons, neutrons, electrons, beta particles and alpha particles |
| Particulate radiation | High speed submolecular particles. Arise from decay of radioactive atoms. Cause more damage to tissue than electromagnetic radiation because has mass and weight |
| 5 examples of particulate radiation are | Protons, Neutrons, Electrons, Beta Particles and alpha particles |
| Electromagnetic Radiation | Travels at the speed of light. Called Photons or Quanta. No mass or weight |
| 7 examples of Electromagnetic Radiation are | Radio waves, Microwaves, infrared, visible light, ultraviolet light, x-rays and gamma rays |
| What are three sources of radiation? | Natural, Artificial and Technological |
| What is considered to be the average radiation exposure to Americans annualy? And what whould be the equivalent number of X-rays? | 360 mrem/year Equal to 36 chest x-rays |
| In exposure from natural background radiation, which is thought to be the largest contributor and what is the mrems/yr exposure? | Radon 222 exposes 198 mrem/year. Which is 55% of all radiation and 67% of natural background radiation |
| Regarding the average annual radiation equivalent dose in the US, What is the mrem/year dose for medical X-Rays? | 40 mrem/year |
| Who discovered X-ray and in what year? | Wilhelm Roentgen 1895 |
| What is considered to be the first intentional X-Ray taken? | He radiographed his wife (Bertas) hand |
| What is considered the first diagnostic X-ray taken? | Dr. Frost x-rayed Eddie McCarthy's wrist for a fracture |
| What was Thomas Edison's contribution to the development of X-ray? | Created first fluoroscope |
| Who is know as the first fatality from radiation exposure? | Clarence Daily (Edison's assistant) |
| In 1907 H.C. Snook developed the interrupterless transformer. How did this impact the future of X-ray technology? | Created high voltage so x-rays didn't take so long |
| In 1913 William D. Coolidge developed the Hot Cathode tube. How did this benefit the future of X-ray technology? | Improved vacuum tube by making it last longer and it heated the filament, which created more electrons |
| When was x-ray introduced to the Chiropractic Profession and by whom? | BJ Palmer in 1910 |
| What year did X-ray become a required course at Palmer School of Chiropractic? | 1922 |
| What are the four types of digitized imaging that still uses Ionizing Radiation? | Computed Radiography, Direct Digital Radiography, CAT Scan and Nuclear Medicine (PET and Bone Scan) |
| What are the three types of digitized imaging that use non-ionizing radiation? | MRI, Ultrasound and thermography |
| What is the Radiation Absorbed Dose (RAD)? | The actual energy absorbed per unit of mass of tissue |
| What is the rad/R ratio of bone vs. soft tissue regarding absorbed dose? | 3.6:1 |
| What is the importance of absorbed dose in tissue like bone vs. soft tissue? | The biological effects of ionizing radiation is closely associated with RAD |
| What is Rad Equivalent Man (REM)? | The universal unit used to represent an equal magnitude of biological effects applied to all types of radiation |
| What is the underlying reason for differences in biological effects of radiation? | The difference is in the nature of the radiation |
| What are the weighting factors for X-ray and Alpha Particles to be used in the equivalent Dose formula Htr=WRDTR when determining radiation dose? | X-ray:1 and Alpha Particles:20 |
| What are the weighting factors for gonads and thyroid to be used in the equivalent dose formula Htr=WrDtrWtr, when determining the individual tissue does of radiation? | Gonads: 0.2 and Thyroid 0.05 |
| What is the unit of measure called the electron volt (eV)? | A unit of X-ray Energy also used to measure the energy of electrons in a circuit of an atom |
| Define Electron Binding energy as it applies to the electron of an atom. | Amount of energy it takes to overcome the binding force |
| What is equilibration of energy? | When a bound electron is removed from orbit, a higher potential energy electron takes it's place and the energy is released in the form of x-ray and heat. |
| Static electricity | Electrons at rest building up on one object and transferring to another by static discharge |
| Dynamic electricity | Electrons in a continuous motion in a circuit |
| 2 types of dynamic electricity are | Alternating current and direct current |
| Alternating current | The movement of electrons that constantly change speed and direction of flow |
| Direct current | The movement of electrons in one direction |
| 2 Types of direct current are | Uniform and Pulsating |
| Uniform current | Remains continuous at peak voltage |
| Pulsating current | non-uniform but continuous |
| What are the three basic factors of a circuit | Voltage, Current and Resistance |
| Voltage | The force applied to electrons to move them |
| Current | The rate of flow of electrons |
| Resistance | The opposition to electron flow |
| Ohm's Law | Current X Resistance |
| Electromagnetic Radiation | An electrical and magnetic disturbance traveling through space at the speed of light |
| What are the 3 parameters describing the waveform of an EM photon? | Frequency, Wavelength and velocity |
| What is frequency? | The number of cycles per second |
| High energy frequencies are | Higher frequency and shorter wavelengths |
| Low energy frequencies are | lower frequency and longer wavelengths |
| Hard X-rays | Higher frequency and higher penetration |
| Soft X-rays | Lower frequency and lower penetration |
| What are the three main components of the X-ray machine? | The tube, Control Console, and transformer assembly |
| What are the 4 things the tube housing does? | Mechanical support for the glass x-ray tube, thermal cushioning, prevents radiation leakage and prevents electrical shock |
| What is leakage radiation? | Radiation that is emitted from any part of the housing other than the port window |
| What is the guideline published by the NCRP to control Leakage Radiation? | Leakage radiation shall not exceed 100 mR/hour at 1m from the tube |
| What are the two parts of the cathode of the tube? | The filament and focusing cup |
| What is thermionic emission and where it is emitted from? | It is when there is enough heat to cause the outer shell electrons of the tungsten to release or boil off. It's emitted from tungsten wire. |
| How many filaments are usually in the tube? | 2 filaments |
| What is the relationship of the boiling off of the electrons and the number of x-rays produced? | Directly proportionate |
| What is the filament and what is it made from? | Tungsten filament. Also made from 1-2% thorium |
| What is the focusing cup regarding the filament and what does it do? | Surrounds the filament and focuses the electron stream |
| Explain the Line Focus Principle regarding effective focus spot | As the largest angle decreases, so does the effective focal spot size |
| Actual Focal Spot | The size of the area on the target that is being exposed to electrons from the cathode |
| Effective focal spot | The focal spot size directly under the target. The smaller the focal spot, the better quality of radiograph |
| What determines the actual focal spot size? | The size of the filament |
| What is the relationship to penumbra and the size of the focal spot? | Small Focus: less penumbra but better detail (C-spine and extremities) Large focus: More penumbra and less detail (Lumbar and chest) |
| How does the focal spot size relate to the sharpness or unsharpness of recorded detail on the film? | Large focal spot: Increases unsharpness and Small focal spot: Increases sharpness |
| Explain the Anode heel effect and its relation to the strength of the primary beam. | Results in uneven exposure. The lesser the Anode angle the greater the heel effect. The intensity of the beam is greatest toward the cathode side. |
| When X-raying a body part that varies in thickness which part of the body thickness do you want the anode side of the tube pointed toward? | The thinnest side |
| Under what circumstances is the Anode Heel Effect less noticeable? | It is less noticeable whith a larger focal spot to film distance. Due to collimation. |
| Please explain what filters do for the X-ray beam | Remove low energy, soft x-rays |
| Explain the Federal law requirements of Beam Energy Filtration. | Less than 50 kVp=0.5mm of aluminum. 50-70k Vp=1.5mm of aluminum. 70-100 k Vp=2.5mm of aluminum |
| Define Inherent Filtration and list its components | 0.5 mm equivalent of aluminum due to the glass port window and the insulating oil around the glass tube |
| Define Added Filtration and list its components | A thin sheet of aluminum at the port area between the housing and collimator and the mirror in the collimator results in 2mm of aluminum. |
| What are the three noted functions of Beam Limiters? | Changes the size and shape of the primary beam. Decreases scatter and increases collimation |
| What are the three types of Beam Limiters? | Aperture diaphragm, cones and cylinders and collimators |
| What are the four types of materials used in compensating filters? | Aluminum, copper, opaque plastics and liquid devices |
| Portal Filters | Are on collimator or tube head. Attenuate beam before reaching patient and reduce direct patient dose |
| Underpart Filter | Placed behind the patient, beam is attenuated after it exposes patient and it does not reduce direct patient dose |
| What are the three types of portal filters? | Nolan filtration system, The Wedge and Clear Pb |
| What are the two types of underpart filters? | Split screens and boomerang filters |
| What are the three types of circuits of the x-ray machine? | High voltage, filament and timer circuits |
| What is the purpose of the high voltage circuit? | To drive electrons from cathode to anode |
| What is the level of the voltage needed in a high voltage circuit? | 40 to 150 KV |
| Explain Rectification of current. | Since the x-ray tube cannot handle electrons moving in both directions the AC input must be converted to DC. |
| Half wave | Half of the overall energy is used making the X-ray inefficient. Produces x-rays in pulses. 2 diodes |
| Full wave | Entire waveform is used doing 120 pulses/sec. 4 diodes |
| Single phase generator | kVp oscillated between peak voltage and zero causing no x-rays at zero, soft x-rays at less than peak and hard x-rays at peak. |
| Three phase | reduces ripple effect. More efficient. Constant high voltage. |
| High frequency | Eliminates ripple effect. Fasture exposre time and less overall exposure |
| What is the purpose of the filament circuit? | Generates electrons in a controllable fashion |
| Define space charge regarding boiling off at the filament. | The electrons repel each other and limit the size of the cloud or electron number by equilibrium. The electrons repulsive strength causes the electrons to boil off. Resulting in no electron cloud. |
| What is the purpose of the timer circuit? | Controls exposure time |
| List the 4 primary factors of exposure. | kVp. mA. Time and distance |
| Explain the function of the kVp factor of exposure. | Determines how fast the electrons travel across the x-ray tube and the qualtiy of the x-ray beam |
| Explain the function of the mA factor of exposure. | Determines the rate of flow of electrons toward the anode and the quantity of x-rays produced. |
| Explain the effect of doubling the mA has on the number of electrons produced at the cathode and the number of x-rays produced consequently. | It doubles the number of electrons. Doubles the number of x-rays produced. Doubles the darkness of the film and increases tube load |
| Explain the effect of doubling the time has on the number of electrons produced at the cathode and the number of x-rays produced consequently. | doubles the number of x-rays produced and doubles the number of electrons hitting the anode |
| Explain distance regarding the inverse square law. | The distance affects the number of x-rays reaching the film. The number of x-rays reaching the film is inversely proportional to the square of the distance from the source. |
| How much of the kinetic energy of the high speed electron at the tube are converted to heat vs. x-ray? | 99% is converted to heat |
| How is the kVp, mA and time related to the Heat produced in the tube? | Heat produced is directly proportional to the kVp, mA and time used for any given exposure or multiple exposure |
| How does vaporization of the tungsten metals cause failure of the tube? | From the excessive heat using high mAs |
| What the procedure for warming up the anode? | Two successive exposures: The first at 50 mA. 50 kVp and 1/30 sec. The second at 100 mA. 50 kVp and 1/30 sec |
| Define Primary radiation | X-rays produced in and emitted from the x-ray tube. They diverge in a forward direction from the focal spot |
| Define central ray | The central point of the primary beam that exits the port window at right angles to the tube and is directed at the center of the structure to be radiographed and to the center of the film. Lowest projectional distortion |
