Radiation Physics Cluster 1 PDF

CLUSTER 1 RTLE 2023 RADIATION PHYSICS Electrical Energy - Done when an electron moves through the electrical potential M...

CLUSTER 1 RTLE 2023 RADIATION PHYSICS Electrical Energy - Done when an electron moves through the electrical potential Matter difference. Electricity Thermal Energy - Energy of motion at the Anything that occupies space and has mass atomic and molecular level. Temperature Distinguishing characteristic of matter is Nuclear Energy - Energy cointained in the Mass (meas. in kg) nucleus of an atom. Nuclear Reaction Atoms Electromagnetic Energy (EMR) - Radiation is a transfer of Energy. Ultrasound is a form of A (not) (Tomon/Tomos) to cut Radiation but not an Ionizing radiation. EMR Building blocks of matter is energy emitted and transferred through space (RADIATION) Mass RADIATION Quantity of matter describe by its energy equivalence Energy emitted and transferred through space Weight IONIZATION Force exerted on the body under the influence of gravity Process by which a neutral atom or molecule acquires a positive or negative charge Molecules IONIZING RADIATION Complex building blocks of matter Kinds of Radiation capable of "removing Energy electron" from the atom with which it Ability to do work interacts Measured in Joule Examples: X-rays, Gamma rays, and UV Light In Radiology, the unit Electron volt is used Ion pair: Negative (Anion) Positive (Cation) Matter and Energy are interchangeable SOURCES OF IONIZING RADIATION (Theory of Relativity) Theory of Relativity - Albert EInstein (E-mc2) Natural Environmental Radiatio Law of Conservation of Energy Annual Dose: 300 mrem/yr Cosmic Rays: emitted by sun & stars Energy may be transofrmed but cannot be Terrestrial Radiation: deposits of uranium, created or destroyed thorium & other radionuclides TYPES OF ENERGY Internally-deposited Radionuclides: K40 (natural metabolites) Potential Energy - IS the ability to do work by Radon: largest source virtue of position Kinetic Energy - Energy of Motion Chemical Energy - Energy released by chemical energy  CLUSTER 1 RTLE 2023 Man-made Radiation DEVELOPMENT OF MODERN RADIOLOGY Annual Dose: 60 to 65 mrem/yr Michael Puppin (1896) Diagnostic X-rays: largest source (39 Demonstrated the use of radiographic IS mrem/yr) Nuclear Medicine (14 mrem/yr) Thomas Edison (1896/98) Consume Product (10 mrem/yr) Industrial Source (2 mrem/yr) Developed Fluoroscopy Original Fluorescent Material: Barium DISCOVERY OF XRAYS Platinocyanide Most Recent: Zinc cadmium sulfide, and Accidentally discovered by Wilhelm Calcium Tungstate Roentgen on November 8, 1895 at Wurzburg University, Germany with the use Charles L. Leonard (1904) of Crookes tube and Barium Platinocyanide Crookes Tube - Forerunner of modern Demonstrated the use of double emulsion fluorescent lamp and Xray tube, invented by film William Crookes. Also known as vacuum tube Clarence Dally (1904) Barium Platinocyanide - Fluorescent First x-ray fatality ever recorded material used by Roentgen Fluorescence - Emission of visible light only William Rollins (Early 1900's) during stimulation 1901 - Roentgen Received Nobel Prize in Demonstrated the first application of Physics collimation and filtration GENERAL TYPE OF X-RAY EXAMINATION H.C. Snook (1907) Radiography Intorduced interrupter less transformer (Snook Transformer) Uses X-ray film and X-ray tube mounted from the ceiling which provides fixed images William Coolidge (1913) Fluoroscopyy Introduced coolidge x-ray tube Moving/Dynamic images Gustav Bucky (1913) X-ray Voltage He invented stationary grid or "glitterblende" Measured in kVp (Quality) Hollis Potter (1915) X-ray Current Invented moving grid Potter bucky (reciprocating grid) was Measured in mA (Quantity) introduced in 1921 LIGHT AMPLIFIER (1946) Demonstrated at Bell Telephone Laboratories  CLUSTER 1 RTLE 2023 1950 Leaded wall - Contain 1.5 mm of Lead Light ampliier was adapted for fluoroscopy UNIT OF MEASUREMENTS 1960 PHYSICS - Study of interactions of matter and energy Diagnostic UTZ and gamma camera THREE BASE QUANTITIES - Mass, Length, appeared and Time SECONDARY QUANTITIES - Combination of 1970 one or more base quantities PET and CT were developed SPECIAL QUANTITIES - Exposure dose, Equivalent dose, and Radioactivity 1980 BASE QUANTITES MRI become an accepted modality. Introduction of CRDR and PACS LENGTH (meter) BASIC RADIATION PROTECTION 1 meter - distance travelled by light ALARA - As Low As Reasonably Achievable MASS (kilograms) Cardinal Principle (STD) - Shielding, Time, Unit of mass Distance Newton or pound - Unit of weight FILTRATION TIME (second) Absorbs low energy x-rays 1 second is the vibration of atoms of cesium atomic clock COLLIMATION OTHER BASED QUANTITIES: Restricts the useful x-ray beam Reduces scatter Radiation Current – Ampere Improves image contrast Size of Molecule – Mole Luminescene - Candela INTENSIFYING SCREEN DERIVED QUANTITIES Reduces x-ray exposure by more than 95% VELOCITY PROTECTIVE APPAREL Speed, measure of how fast something is Lead-Impregnated Material moving or, more precisely, the rate of change of its position with time Examples: Gloves, Shields, Apron SI: meter/second (m/s) GONADAL SHIELDING Used with all persons of childbearing age For Average Velocity PROTECTIVE BARRIERS Lead-lined with a leaded-glass window Complete concrete wall - 6 in. thick  CLUSTER 1 RTLE 2023 ENERGY The ability to do work ACCELERATION Energy may be transformed from one to Rate of change of velocity with time is another, but it cannot be created not acceleration (How quick or slow) destroyed Acceleration is velocity divided by time, the units meter per second 2 (m/s2) Joule (J) NEWTON'S LAW OF MOTION vf - is for final velocity, LAW OF INTERTIA - Body will remain at rest while vo is for initial velocity. or continue to move unless acted on by an external force (push/friction) WEIGHT LAW OF FORCE - Force (f) on acting on an is a force on a body caused by the downward object is equal to the mass (m)object pull of gravity on it multiplied by the acceleration (a) produced. The unit is Newton (N) or pounds (lbs) Force can be thought as push or pull Wt= (m)(g) (F=(m)(a)) MOMENTUM LAW OF ACTION/REACTION - For every action, there is an equal and opposite The product of mass and velocity reaction. Action was Newton's word for Total momentum before any interaction is Force equal to the total momentum after the HEAT interaction Kinetic energy of the random motion of Represented by p molecules P = (m)(v) Transfer by conduction, convection, and radiation WORK Conduction Force applied times the distance over which it is applied The transfer of heat through a material by touching Unit is Joule (J) Convection W = (F)(d) The mechanical transfer of “hot” molecules POWER in a gas or liquid from one place to another Rate of doing work SI unit is Joules/second (Watt)  CLUSTER 1 RTLE 2023 Thermal Radiation Number of nuclear disintegrations per unit time. The transfer of heat by the emission of infrared radiation FUNDAMENTALS OF RADIOLOGIC SCIENCE An x-ray tube cools primarily by radiation Customary Unit International SI Quantity Name Symb Name Symb RADIOLOGICAL UNITS ol ol Exposure Roentg R Air Gya ROENTGEN (R) = AIR KERMA (GYa) en kerma The Roentgen is the unit of radiation Absorbed Rad Rad Gray Gyt exposure or intensity dose Effective Rem Rem Sievert Sv Amount of radiation and is defined as the Dose charge liberated per unit mass of air Radioactiv Curie Ci Becquer Bq ity el Applies only to x-ray and gamma rays and STRUCTURE OF MATTER their interaction with air CENTURIES OF DISCOVERY Kinetic Energy Released per unit Mass GREEK ATOM C/kg Atomos means indivisible rad = Gray (Gyt) Four substances: earth, water, air, and fire Radiation Absorbed Dose four essences: wet, dry, hot, and cold Radiation Absorbed by a patient JOHN DALTON (1808) Measure of the effect of radiation and is Dalton's atomic model: Hook & Eye Affair defined as the energy absorbed by a unit (Dalton Atom) mass of a substance Showed that elements could be classified J/kg according to integral values of atomic mass Rem = Sievert (Sv) JOSEPH JOHN THOMSON Radiation Equivalent Man Thomson's atomic model: Plum Pudding (Thomson Atom) Dose equivalent Plum: Negative electric charges (Electrons) Effective dose Pudding: A shapeles mass of positive Equivalent dose electrification Used to express the quantity of radiation Investigated the physical properties of received by radiation worker and population cathode rays (discovered electrons) J/kg/min Concluded that electrons were integral parts Curie (Ci) = Bequerel (Bq) of all atom Curie is the unit of radioactivity  CLUSTER 1 RTLE 2023 ERNEST RUTHERFORD (1911) Particle Acceleartor Ernest Rutherford Model: Nuclear Model Atom Smaher Discovered and termed the "center" as the Used in mapping the structure of atomic nucleus (small, dense, poositively charge nucleus center ) NUCLEONS NEILS BOHR (1913) Protons (+) and Neutrons (O) Neil's Bohr atomic model: Mini Solar System Composed of quarks and gluons (subatomic Improved Rutherford's atomic model particle) Electrons revolve in a fix, well-defined orbit Electron (electron orbital shells) around the nucleus like a planet Location: orbital shells Mass in kg: 9.1 x 10-31 Bohrs model is the most useful model for the Mass in amu: 0.000549 study of interaction of radiation to the Number: 0 atoms because of the models represent the Charge: -1 electron orbiting in electron shell Symbol: - most convenient way to study electron Proton Dmitri Mendeleev Location: nucleus Mass in kg: 1.673 x 10-27 Made the first periodic table of elements Mass in amu: 1.00728 arranged with their atomic number (number of protons) Number: 1 Charge: 1 Consist of 118 elements Symbol: + FUNDAMENTAL PARTICLES Neutron ATOM Location: nucleus Mass in kg: 1.675 x 10-27 Empty space, neutral charge Mass in amu: 1.00867 Nuclear portion holds the protons and Number: 1 neutrons while the extra nuclear portions is Charge: 0 where electrons are located Symbol: O extra nuclear portion has an electron orbital LOCAT MASS MASS CHA SYM shells, an invisible path that electrons make ION IN kg IN RGE BOL as they orbit around the nucleus nearly in amu the same as theat of light in a fixed distance Elect Orbita 9.1x1 0.000 -1 - from the nucleus ron l shells 0-31 549 99% weight of the atom is in the nucleus Prot Nucle 1.673 1.007 1 = on us x10-27 28 (center of the atom) while the 1% is in the Neut Nucle 1.675 1.008 1 O extra nuclear portion ron us x10-27 67  CLUSTER 1 RTLE 2023 ATOMIC MASS UNIT: ELECTRON BINDING ENERGY The mass of a neutral atom of an element Strength of attachment of an electron to the nucleus. Symbol: amu Total # of Electrons in an atom, and strength ATOMIC MASS NUMBER of binding energy - Directly Related Number of protons plus number of neutrons ATOMIC NOMENCLATURES in the nucleus Symbol: A Number of Protons Determine the chemical behavior of an atom Determine the chemical element Isotopes Same number of protons, but different number of neutrons NUCLEAR ARRANGEMENT Electron Arrangement The number of electrons in the outermost shell of an atom = group in the periodic table & determines the valence of an atom No outer shell can contain more than 8 electrons (Octet Rule) The number of outermost electron shell of an atom = period in the periodic table Maximum Electrons Per Shell PSZ - IsotoPe, Same Atomic Number (Z) Formula: 2n2 BSA - IsoBar, Same Atomic Mass (A) NSN - IsoTone, Same Neutron Number (N) Principal Quantum Number MSS - IsoMer, Same in all aspect, but differ in energy The shell number (n) state (Metastable) Centripetal Force COMBINATION OF ATOMS Center-seeking force (pull) COVALENT BONDS - SHARING. Example: H2O IONIC BONDS - GIVING DUE TO The force that keeps an electron in orbit ELECTROSTATIC FORCE. Example: NaCI Centrifugal Force MOLECULES - Group of atoms, smallest unit of a compoud Flying-out-from-the-center force (fly) The force that causes an electron to travel WATER - 80% of the Human body straight and leave the atom  CLUSTER 1 RTLE 2023 RADIOACTIVITY Produced in Nuclear Reactors 1 Neutron is converted into a positive and RADIOACTIVITY negative Emission of particles and energy in order to Increase in Atomic number by 1 become stable Isobaric Transition RADIONUCLIDE BETA PLUS DECAY Atoms invovled and the only nuclei that Positron Decay, Proton Rich undergoes radioactive decay One proton is converted to a neutron and a RADIOACTIVE DISINTEGRATION/RADIOACTIVE positive electron called "Positron" DECAY Emission of Positron (Antimatter) and a Neutrino Nucleus emits particles and energy to transform itself into another atom to reach Produced in Cyclotron stability 1 positive is converted into a Neutron and a positron HALF LIFE Decrease in atomic number by 1 Time required for a quantity of radioactivity Isobaric transition to be reduced to one-half of its original value ELECTRON CAPTURE/K CAPTURE DECAY Half life starts at 50%. 100% is the original value (does not count as half life activity) Positron Rich Nucleus Proton is converted into a Nuetron Produced in Characteristic X-rays from the K-shell positive is converted into a neutron Decrease in atomic number by 1 Isobaric Transition GAMMA DECAY Excess energy in the nucleus is being released in the form of gamma ray Radioactive decay formula: Activity Metastable state Remaining = (Original value/activity)(0.5)n No change in atomic number (number of half-lives) Isomeric Transition ALPHA DECAY/HELIUM NUCLEUS Proton and Neutron Rich Alpha particles - Most ionizing and destructive type, least penetrating -2 proton and -2 neutron (A-4) BETA MINUS DECAY Negatron Decay/Emission, Neutron Rich Emission of Negaton and an Anti-Neutrino  CLUSTER 1 RTLE 2023 DECAY Mass Atomic Neutron Small bundle of energy MODE No. No. (Z) No. (N) (A) X-ray photon is quantum of Electromagnetic (Z+N) Energy GAMMA SAME SAME SAME JAMES CLERK MAXEWELL (LATE 19th CENTURY) ISOMERIC DECAY AND Shoed that visible light has both electrical INTERNAL and magnetic properties CONVERSION BETA MINUS SAME Z+1 N-1 PROPERTIES OF PHOTONS BETA PLUS SAME Z-1 N+1 ISOBARIC ELECTRON SAME Z-1 N+1 Three Wave Parameters CAPTURE ALPHA A-4 Z-2 N-2 Velocity, Frequency & Wavelength DECAY VELOCITY Is MERe GAMMA METASTABLE I SO BAR, BETA, and ELECTRON CAPTURED Photons are energy distrubance moving ALPHA DECAYS by 4 through space at the speed of light (3x108m/s) NONIONIZING RADIATION Velocity of all EMR is 3x108m/s (Speed of Radiation that are not capable to remove or Light) eject an outer shell electron Constant SI unit: Speed of Light Types of NonIonizing radiation in Radiology Field: UTZ, AND MRI AMPLITUDE ELECTROMAGNETIC RADIATION One half range from crest to valley ocer which the sine wave Electromagnetic energy exists over a wide range called an energy continuum. A Width of a waveform continuum is an uninterrupted (continuous) ordered sequence. SINE WAVE PHOTON Variation in the movement of photons in electrical and magnetic fields Smallest quantity of any type of electromagnetic energy. FREQUENCY A photon may be pictured as a small bundle Rate of Rise and Fall of energy, sometimes called a quantum, that travels through space at the speed of light Symbol: f (3 × 108 m/s.) SI Unit: hertz (Hz) No Mass, no Charge 1 Hz: 1 cycle/second Waveform: Sinusoidal Fashion It is equal to the number of crests or valleys Photon energy and Frequency is Directly that pass the point of an observer per unit proportional time QUANTUM It is inversely proportional to the wavelength  CLUSTER 1 RTLE 2023 Direcly proportional to Energy Xray Region: Fundamental to producing a high quality radiograph Number of wavelength that pass a point of observation per second Radiofrequency Region: Fundamental aspect in Magnetic Resonance Imaging Wavelength (λ) Ultrasound Represented by Greek symbol λ or Lambda The wave of moving molecules Distance from One Crest to another / One It requires matter Valley to another It cannot exist in vacuum One point on the sine wave to the next corresponding point Visible Light It is described in terms of wavelength Inversely proportional to the Frequency Measured in nanometer (nm) WAVE EQUATION Interacts with rods and cones of the eye These are used for both sound & electromagnetic energy Red has the longest wavelength (700nm) but the shortest frequency. Violet has the FORMULAS: highest Frequency but shortest wavelength (400nm) in the ROYGBV Refraction Deviation of course that occurs when photos of visible light traveling in straight lines pass from one transparent medium to another Sunlight 2 Invisible Light: infrared & UV light ELECTROMAGNETIC WAVE EQUATION Infrared Formula: c = fλ Longer λ than visible light ELECTROMAGNETIC SPECTRUM Shorter λ than microwaves a continuum of electromagnetic energy It heats any substance on which it shines REAL MEN IN VEGAS USES XRAY GOGGLES (radiant heat) All travel in the speed of light: 3 x 10 ^ 8 m/s UV Light (186,000 mi/sec. It is constant It causes sunburn THREE REGIONS IMPORTANT TO RADIOLOGIC Lies between visible light & ionizing radiation SCIENCE Interacts with molecules Visible Light Region: Viewing condition of a Radiographic and Fluorscopic Images are critical to diagnosis  CLUSTER 1 RTLE 2023 Radiofrequency WAVE-PARTICLE DUALITY Range: 0.3 kHz-300 GHz Photons interact with matter most easly when the matter is approximately the same Range in MRI: 1-100 mHz size as the photon wavelength The principle that states that both wave & Low energy & long wavelength particle concepts must be retained, because Microwave wave-like properties are exhibited in some experiments & particle-like properties are Very-short wavelength RF exhibited in others Higher than broadcast RF WAVE MODEL: VISIBLE LIGHT Lower than infrared Shortest wavelength (violet) extends up until the longest wavelength (red) in the VL Interacts with hotdogs and hamburgers spectrum Sense by human eye Ionizing Radiation Behaves like a wave Higher energy & lower wavelength ATTENUATION Capable of ionization Attenuation is the reduction of strength or intensity of x-ray as it passes through matter XRAYS AND GAMMA RAYS Reduction in intensity that results from Only forms of ionizing electromagnetic scattering and absorption radiation of Radiologic Interest Lucent (Lucency) Differs in Origin: Xrays in Electron Cloud. Gamma in Nucleus/Radioactive Nuclei Description to area of less density/ clear Ability to transmit light X-rays Radiolucent It is emitted from the electron cloud Transmit X-rays e.g., Lung tissue It is produced in diagnostic imaging systems Appears black in the radiograph Interacts with electrons Opaque (opacity) behaves as though they are particles description to area of more density of blackness Polyenergetic/heterogenous prevents light transmission absorbs light Gamma Rays Radiopaque It comes from inside the nucleus of radioactive atom Absorbs the xray e.g., Bones It is emitted spontaneously from radioactive Appears white in the radiograph material  CLUSTER 1 RTLE 2023 INVERSE SQUARE LAW Total amount of energy is constant State that intensity of radiation at a location ELECTRICITY, MAGNETISM, AND is inversely proportional to the Square of distance from the source of radiation ELECTROMAGNETISM If SID is Doubled, Density is reduced to 1/4 Electrostatics Distance from the source mainly affect the Study of stationary electric energy into Denisty of the Radiograph electromagnetic energy Long distance/Wavelength, Decrease Electric charge distribution is uniform Density throughout or on the surface (Law of Distribtion) Electric charge of a conductor is concentrated along the sharpest curvature of the surface (Law of Concentration) Max Planck Electric Potential: He synthesized our understanding of electromagnetic radiation Si Unit: volt (V) 1918: He received the Nobel Prize Electrification PARTICLE MODEL: MAX PLANCK'S QUANTUM Transfer of electric charges can be created THEORY by contact, friction and induction X-rays are identified by their energy (eV) and Electrostatic Law created with the speed of light (c) and they Like charges repel, unlike charges attracts. exist with velocity (3 × 108 m/s) Uncharged particles do not have electric Energy: 10 keV-50 MeV field. Wavelength: 10-10 - 10-14m Electric Field Frequency: 1018 - 1022 Hz Causes charged particles to move from one pole to another All electromagnetic radiation can be visualized as two perpendicular sine waves Positive charge: Outward (electric & magnetic fields) that travel in a Negative charge: Toward straight line at a speed of light Electrostatic Force MATTER & ENERGY The force of attraction between Law of Conservation of Matter unlikecharges or repulsion between like It states that matter can be neither created charges nor destroyed Directly proportional to the product of the Law of Conservation of Energy charges It states that energy may be transformed Inversely proportional to the square of the from one form to another but cannot be distance between them created or destroyed  CLUSTER 1 RTLE 2023 Coulomb’s law Can be conductive The electrostatic force is directly basis of computer proportional to the product of the electrostatic charges and inversely Example: Silicon, & Germanium proportional to the square of the distance between them. Superconductor Law of distribution Any material that allows electrons to flow without resistance Electric Charge distribution of charges is uniform throughout or on the surface Characteristics: ELECTRODYNAMICS No resistance Study of Electric Charge in Motion No electric potential required (voltage) Conductors Must be very cold/extreme low Any substance through which electrons flow temperature easily Example: Niobium and titanium Requires voltage to move the electron Superconductivity Characteristis: Property of some matter to exhibit no Variable resistance- force that resist the resistance below a critical temperature flow of electrons Electric Circuits Obeys OHM's Laaw Path of electron flow from the generating Example: Copper, Aluminum, & Water source through the various components and back again Insulator Electric Current/Electricity Any substance that does not allow electrons to flow Flow of electron through a conduction Characteristics: Direction: Always opposite the electron flow Extremely high resistance Measured in Amperes (A) Necessary with high voltageas insulation Electric Resistance (to protect from electrocution) Measured in ohms Example: Glass, Rubber, & Clay Increasing electric resistance results in a Semiconductor reduced electric current Materl that sometimes behave as insulator and sometimes as a conductor Characteristics: Can be resistive  CLUSTER 1 RTLE 2023 OHM'S LAW ALTERANTING CURRENT Voltage across the total circuit or any portion Electron flows alternately in opposite of the circuit is equal to the current times the direction resistance Electrons flow first in a positive direction and Formula: then in a negaative direction Sinusoidal wave MAGNETISM Oxide of iron (Fe3O4) rodlike stone moving back and forth also called as lodestone or leading stone Magnetic field Any charged particle in motion creates magnetic field TWO TYPES OF ELECTRIC CIRCUIT: Magnetism 1. Series Circuit Milk of magnesia from cows of the North All circuit elements are connected in a line pole along the same conductor Electron spin All are equal each circuit element (Resistance, Voltage, and Current) Magnetic field created by rotating electron on its axis or counterclockwise 2. Parallel Circuit Creates a/the magnetic field Elements are connected at their ends rather than lying in a line along a conductor Magnetic moment The sum of the currents through each circuit Protons of hydrogen spin on its axis creates element is equal to the total circuit current. nuclear magnetic dipole The voltage across each circuit element is the Basis of MRI same and is equal to the total circuit voltage. DIPOLAR/BIPOLAR The total resistance is the inverse of the sum A Magnet that has two pole (North and of the reciprocals of each individual South Pole) resistance. Magnetic dipole DIRECT CURRENT Small magnetic field created by electron Electrons flows only in one direction orbit Straight line Magnetic domain Accumulation of many atomic magnets with aligned dipoles, randomly distributed  CLUSTER 1 RTLE 2023 Magnetic permeability Paramagnetic - Weakly Attracted (example: Gadolinium) Is the ability of a material to attract the lines Par-Par of magnetic field intensity Ferromagnetic - Strongly magnetized (example: Iron, Nickel, Cobalt) Magnetic Susceptibility suFFERor magnetized The degree to which a material can be MAGNETIC INDUCTION magnetized is its magnetic susceptibility Wood - Low magnetic susceptibility Process of making ferromagnetic material Iron - High magnetic susceptibility magnetic Hysteresis - A condition wherein some materials that are very susceptible are also Magnetic Force reluctant to losetheir magnetism The force of attraction between unlike poles THREE PRINCIPAL TYPES OF MAGNET or repulsion between like poles Directly proportional to the product of the Naturally Occurring Magnets magnetic pole strengths Artificially Produced Permanent Magnents Inversely proportional to the square of the Electromagnets distance between them Types of magnets Magnetic Field Strength Naturally occurring magnets: SI Unit: tesla (T) Older Unit: gauss (G) magnet that gets its magnetic properly from 1 T: 10,000 G the earth HANS OERSTED (1820) LAW OF Example: Lodestone (lead stone) - Magnesia ELECTROMAGNETISM Permanent Magnets Demonstrated that electrcity can be used to Magnets whose magnetism is induced generate magnetic fields artificially Oersted Law states that any charge in motion induces a magnetic field A bar of horseshoe-shaped magnet Electric current produces a mechanical motion which is the basis of the electric Example: Compass motor Electromagnet SOLENOID A coil of wire wrapped around an iron core A coil of wire that intensifies the magnetic field\ ELECTROMAGNET FOUR MAGNETIC STATE OF MATTER A current-carrying coil of wire wrapped Non Magnetic - Unaffected (example: around an iron core wood) Intensifies the induced magnetic Non (Wala) Advamtage: Magnetic field can be adjusted Diamagnetic - Weakly Repelled (example: or turned on and off water and plastic) Dia (Di Kaya)  CLUSTER 1 RTLE 2023 MICHAEL FARADAY'S LAW OF ELECTROMAGNETIC STEP-UP TRANSFORMER INDUCTION Turns ratio greater than 1 First law of electromagnetism Primary Side: low voltage, high current Observed the current in a changing magnetic Secondary Side: high voltage, low current field STEP-DOWN TRANSFORMER Magnitude of the induced current depends on four factors: Turns ratio less than 1 Primary Side: high voltage, low current (1) Strength of magnetic field Secondary Side: low voltage, high current (2) Velocity of magnetic field as it passes the conductor EFFECT OF TRANSFORMER LAW ON CURRENT (3) Angle of conductor to the magnetic field (4) Number of turns in conductor Change in current and a change in voltage are inversely related ELECTROMAGNETIC DEVICES ELECTRIC MOTOR Electric current produces mechanical motion Commutator Ring: switches the direction of current through the loop TYPE OF TRANSFORMERS (3) ELECTRIC GENERATOR CLOSED-CORE TRANSFORMER Mechanical motion produces electric current Square core of ferromagnetic materials built TRANSFORMER up of laminated layers of iron Helps to reduced energy losses caused by It changes the intensity of alternating voltage eddy current & current Greater efficiency It works on AC only EDDY CURRENT DC: induces no current in the secondary coil Current that opposes the magnetic field that induced it, creating a loss of INDUCTION MOTOR transformer efficiency A type of motor used with x-rays tubes AUTOTRANSFORMER It powers the rotating anode of an x-ray tube Consist of one winding of wire and varies in TRANSFORMER LAW voltage and current by self-induction Located in the opening console that controls The change in voltage is directly proportional the kVp to the ratio of the number of turns (windings) in the secondary coil (Ns) to the SHELL-TYPE TRANSFORMER number of turns in the primary coil (Np) Formula: Confines more of the magnet field lines of primary winding More efficient than the closed core transformer Vs – Secondary Circuit, Vp – Primary Circuit, Ns – Secondary coil turn ratio, Np – Primary coil turn ratio  CLUSTER 1 RTLE 2023 XRAY IMAGING SYSTEM RADIATION QUALITY (kVp) THREE MAIN COMPONENTS OF XRAY IMAGING Pertains to the Quality and Penetrability of the X-ray beam (1) Operating Console Controlling factor of Voltage (2) High voltage Generator Expressed in kVp or Have Value layer (HVL) (3) Xray tube LINE COMPENSATOR FLUOROSCOPIC XRAY TUBE Measures the voltage provided to the xray Located under the X-ray table imaging system and adjust that voltage to pricesely 220v RADIOGRAPHIC XRAY TUBE AUTOTRANSFORMER Attached to an overhead movable crane assembly that permits easy positioning of Consist of only one winding of wire and one the tube core Supplies a precise voltage to the filament EXAMINATION COUCH.TABLE circuit, and high voltage-circuit Must be transparent to x-rays as possible Designed to step up voltage to approximately Carbon Fiber couches: strong and asbrob twice the input voltage value little radiation. Reduces patient radiation Controls the kVp dose Operates as an induction device HIGH VOLTAGE GENERATOR AUTOTRANSFORMER LAW Housed in an equipment cabinet positioned States that the voltage receive and provide against a wall by the transformer is directly proportional to Close to the x-ray tube the number of turns Newer generator design less space Vs/Vp = Ns/Np OPERATING CONSOLE KVP METER Most familiar to the radiologic technologist Placed across the output terminals of the Used to control the x-ray tube current and autotransformer voltage applied to the xray tube Actually reads voltage, not kVp It provides control of Line compensation, Pre-reading kVp meter: allows the voltage to kVp, mA and exposure time be monitored before an exposure Most xray systems are designed to operate FILAMENT TEMPERATURE on 220v power Controlled by the Filament current, RADIATION QUANTITY (mAs) determines the number of electrons emitted Number of x-rays by the filament Intensity of the x-ray beam FILAMENT CURRENT Controlling factor of Current, High number of electrons, Higher heat provided to the xray Measured in Amperes (A) tube Xray tube is controlled through a separate Units: mR, mGy or mR/mGya, mAs, circuit called Filament Circuit Opeartes at currents of 3 to 6 Ampere  CLUSTER 1 RTLE 2023 SPACE CHARGE EFFECT TIMER CIRCUIT Phenomena Via Electrostatic Repulsion Consist of an electronic device whose action Electron cloud near the filament is to “make” and”break” the high voltage across the xray tube THERMIONIC EMISSION Done on the primary side of the highvoltage transformer Release of electrons from a heated filament 4 (Four) types of timing circuits o Synchronous Timer PRECISION RESISTORS o Electronic Timer Used to reduce the voltage to a value that o mAs Timer corresponds to the selected milliamperage o AEC (Automatic Exposure Control) FALLING LOAD GENERATOR SYNCHRONOUS TIMER Exposure begins at maximum mA, then Motor driven drops as the anode heats which results in Precision device designed to drive a shaft at minimum exposure time pricesely 60 rev oer second Cannot be used for serial exposures MILLIAMPERAGE x EXPOSURE TIME (mAs) ELECTRON TIMER Product of x-ray tube current (mA0 and exposure time is mAs Most sophisticated, complicated, and Measure of Electrostatic Charge (C) accurate of the x-ray exposure timers Allows a wide range of time intervals to be MA METER selected and are accurate to intervals as small as 1ms Monitors the xray tube current Used for rapid serial exposures, suitable for Connected at the center of the secondary interventional radiology winding of the high-voltage setup Most exposure timers are Electronic transformer Ensures electrical safety MAS TIMER FILAMENT TRANSFORMER Monitors the product of mA and exposure time (Electrostatic Charge – C) “Filament heating isolation step-down Termiantes exposure when desired mAs transformer” value is attained Receives the voltage from the mA selector Provides the highest safe tube current for the switch shortest exposure for any mAs selected Steps down the voltage to approx.. 12 v Provides current to heat the filament AUTOMATIC EXPOSURE CONTROL PRIMARY WINDING: Thin copper, 0.5 to 1Ampere, 150v approximately Device that measure the quantity of SECONDARY WINDING: Thick, 5 to 8Ampere, radiation that reaches the IR 120 V It automatically terminates the exposure when the IR has received the required EXPOSURE TIMERS radiation intensity GUARD TIMER SOLID-STATE DETECTORS (SSD) Terminate exposure after prescribed time It is used to check timer accuracy (as short 1 (6s) ms)  CLUSTER 1 RTLE 2023 HIGH VOLTAGE GENERATOR DIODE Increases the output voltage from the Electronic device that contains two autotransformer to the kVp necessary for x- electrodes ray production All diode rectifers were vacuum tubes called Heat generated is conducted oil the oil is Valve tubes (Replaced by Solid-State used primary for electrical insulation (DIALA Rectifers made up of Silicon) V OIL) SEMICONDUCTOR THREE PRIMARY PARTS Between Insulator and conductor in the High Voltage Transformer, Filament ability to conduct electricity Transformer, and Rectifiers P-TYPE SEMICONDUCTOR HIGH VOLTAGE TRANSFORMER Have loosely bound electrons (free to move) Step Up transformer Have spaces called holes (no electrons) Secondary Voltage (kVp) > Primary Voltage Holes: as mobile as electrons (V) Secondary Current (mA) < Primary Current SOLID-STATE P-N JUNCTION (A) Secondary Windings > Primary Windings N-type material placed in contact with p- Voltage waveform: Sinusoidal type crystal It conducts electricity in only one direction TURNS RATIO Solid-State Diode: a rectifier Ratio of the number of secondary windings HALF-WAVE RECTIFICATION to the number of primary windings Example: 500:1 and 1000:1 Contains 0, 1, or 2 diodes Directly proportional to the voltage Voltage is now allowed to swing negatively Inversely proportional to current during the negative half of its cycle Producing 60xray pulses/per second RECTIFICATION Wastes half the supply of power and requires twice the exposure time Process of converting AC to DC Xray are produced by the acceleration of FULL-WAVE RECTIFICATION electrons from cathode to the anode and cannot be produced by electrons flowing in Contains atleast 4 diodes the reverse direction (Direct Current) Negative half-cycle corresponding to the inverse voltage is reverse VOLTAGE RECTIFICATION 120xray pulse/second Exposure time is cut in half Ensures that electrons flow from cathode to Used in almost all stationary x-ray anode only SINGLE-PHASE POWER RECTIFER Results in a pulsating x-ray beam Electronic device that allows current to flow Xray produced has a value near zero in only one direction Single Phase Halfwave voltage ripple: 100% Single Phase Fullwave voltage ripple: 100% Votage varies from zero to maximum  CLUSTER 1 RTLE 2023 THREE-PHASE POWER Formula: for single-phase o (0.7)(mA x kVp)/1000 Voltage impressed across the x-ray tube is nearly constant THE XRAY TUBE 6 pulses per 1/60 second Voltage never drops to zero during exposure XRAY TUBE Has a disadvantage interms of its size and Special type of diode (anode and cathode) cost Converts electrical energy to Requires 10-kVp reduction electromagnetic energy 6-Pulse voltage ripple: 14%. Voltage never falls below 86% DIODE 12-Pulse voltage ripple: 4%. Voltage never falls below 96% Tube with two electrodes HIGH FREQUENCY EXTERNAL COMPONENTS Produces nearly constant potential voltage SUPPORT SYSTEM waveform Much smaller and less costly and more Helps the RT position the x-ray tube efficient accordingly Improves image quality at a lower Px dose Requires a 12-kVp reduction CEILING SUPPORT SYSTEM ) 100 rad (1 Gyt) DETERMINISTIC RADIATION RESPONSE CLINICAL SS: Nausea, Vomiting, and Diarrhea Acute radiation effect LATENT PERIOD Death – most devastating human response to radiation exposure Time after exposure during which there is no Three Mile island incident (1979( sign of radiation sickness Chernobyl in April 1986 Approximate: 100-10,00 rad (1-100 Gyt) o Thirty people at Chernobyl CLINICAL SS: none experienced acute radiation syndrome and died HEMATOLOGIC SYNDROME PRINCIPAL EARLY EFFECTS OF RAD EXPOSURE ON It is characterized by a reduction in white HUMANS AND APPROXIMATE TRESHOLD DOSE cells, red cells, and platelets Approximate: 200-1000 rad (2 to 10 Gyt) EFFECT ANATOMIC TRESHOLD Mean Survival time: 10-60 days SITE DOSE CLINICAL: o Vomiting Death Whole Body 200 rad/2 Gyt o Diarrhea o Anemua Hematologic Whole Body 25 rad/250 o Leukopenia Depression mGyt o Hemorrhage o Fever and infection Skin Erythema Small Field 200 rad/2 Gyt At Prodomal Period: Mild Epilation Small Field 300 rad/3 Gyt At Latent Period: General feeling of wellness Period of Manifest Illness: Vomiting, mild Chromosome Whole Body 5 rad/ 50 diarrhea, Malaise, Lethargy, and Fever Aberration mGyt Recovery: 2-4 weeks or 6mos full Cause of Death: Generalized infection, Gonadal Local Tissue 10 rad/100 electrolyte imbalance and dehydration Dysfunction mGyt GI PERIOD It occurs principally because of severe ACUTE RADIATION SYNDROME damage to the cells lining the intestines Approximate Dose: 1000-5000 rad (10 to 50 Radiation sickness that occurs in human after Gyt) the whole-body dose of 1 Gy (100 rad) or Mean Survivtal time: 4-10 days more of ionizing radiation delivered over a CLINICAL: Same as hematologic plus short time electrolyte imbalance, fatigue, and shock THREE SYNDROMES Prodomal Period: Vomiting and diarrhea Latent Period: No symptoms present Hematologic Death, Gastrointestinal (GI) Period of Manigest Illness: Second wave of death, and CNS Death nausea and vomiting, followed by diarrhea and anorexia Cause of Death: Unprevented rapid progression of symptoms  CLUSTER 1 RTLE 2023 CNS PERIOD Skin Erythema – Requires to affect 50% of those irradiated (SED50) is about 5 Gyt (500 Ultimate cause is elevated fluid content of rad) the brain o Increased Intracranial pressure EPILATION (HAIR LOSS) o Vasculitis o Meningitis Grenz rays (soft xrays) – 10 to 20 kVp Approximate Dose: Greater than 5000 rad (Greater than 50 Gyt) EFFECTS ON GONADS o May result in death within hours Mean survival time: 0-3 days GONADS Clinical S&S: same as GI plus ataxia, edema, system vasculitis & meningitis 10 RAD Menstrual delauy More Prodomal Period: severe nausea & vomiting Than Latent Period: earlier symptoms disappear 200 RAD Temporary Period of Manifest Illness: more severe Plowers Infertility prodomal symptoms, disoriented, loss muscle coordination, dyspnea, convulsive 500 RAD Permanent seizures, loss of equilibrium, ataxia & Sterility lethargy 25-50 RAD Increase genetic Pag may range LD 50/60 mutation starting from 25 50% of irradiated subjects to die within 60 (increase) gang days 50 MEAN SURVIVAL TIME TESTES As the whole-body radiation dose increases, average time between exposure and death 10 RAD Reduce Reduce Sperm decreases number of spermatozoa LOCAL TISSUE DAMAGE 200 RAD Temporary TempPer Certain part of the body is being irradiated, Infertility in contrast to whole body irradiation in which requires higher dose for a response 500 RAD Permanent o Leads to lack of function of Sterility organ/tissue or by recover o Atrophy – shrinkage of organ/tissue SKIN HEMATOLOGIC EFFECTS Limitation of radiation – Orthovoltage xrays 25 rad (250 mGy) measurable hematologic (200-300 kVp xrays) depression o Result to Erythema – Sunburn-like Decrease number of all the types of blood reddening of the skin (3-10 Gy) cells o Followed by Desquamation – o Lethal injury inv. Depletion of Ulceration and denudation of the mature circulating cells skin Lymphotcytes – first affected. o Depletion occurs in minutes/hrs  CLUSTER 1 RTLE 2023 HEMOPOIETIC CELL SURVIVAL Students – 50 mSv (older than 18 y/o) General Pub – 1 mSv for frequent exposure. Response: Decrease in the number of all 5 mSv for infrequent exposure types of blood cells in the circulating Embryo Fetus – total equivalent dose for peripheral blood gestation is 5 mSv. Cells are reduced in number (lymphopenia) o 0.5 mSv per equivalent dose per within minutes or hrs after exposure and are month very slow to recover Granulocyte and Thrombocytes – 30 days CARDINAL PRINCIPLES (STD) after irradiation. o 2 months recovery Shielding Erythrocytes – less sensitive than other blood cells Positioning shielding between the radiation o 6 mos to 1 yr total recovery source and exposed persons greatly reduces the level of rad exposure. CYTOGENETICS One TVL is the thickness of absorber that reduces rad intensity Study of the genetics of cells (cell Protective aprons usually contain 0.5 mm Pb chromosomes) o Equialent 2 HVLs Radiation-induced chromosome abberations o Reduce occupational exposure to follow a non-treshold dose response 25% relationship (stochastic) 1 TVL = 3.3. HVL Half value layer (HVL) – Thickness of HEALTH PHYSICS absorber necessary to reduce radiation intensity to half its original value Concerned with providing occupational Tenth Value layer (TVL) – reduce radiation radpro and minimizing radiation dose to the intensity to one-tenth its original value public Health Physicst – radiation scientist who is TIME concerned with health physics in rad safety ALARA – As Low As Reasonably Achievable Minimize time. Dose of an individual is Clarence Dally – First American fatality directly related to the duration of radiation resulted from radiation exposure. epxposur o Was Thomas Edisons’s Assistant ICRP – International COmission on DISTANCE Radiological Protection conducts research and provides recommendation on radpro Distance between the source of radiation worldwide and the person increases, radiation exposure NCRP – National council on Radiation decreases rapidly. Inverse square law protection and Measurements formulates EFFECTIVE DOSE and publishes scientifically researched recommendations on radpro and Patient radiation exposure and dose during measurements in the US medical xray imaging Whole body dose NCRP REPORT# 116 Weighted average dose to each tissue Occupational Exposure – Annual efective Assume the occupational effevtive dose to dose limit is 50 mSv be 10 monitor dose o Lens of the eye – 150 mSv o Skin, Hands, Feet – 500 mSv Cumulative effective dose (CEfD) – Age x 10 mSv  CLUSTER 1 RTLE 2023 RADIATION PROTECTION GUIDANCE MONITORING DEVICES Inner boundary is established at an exposure Optically Stimulated Luminescence rate of 100 mGya/hr (10R/hr) Outer boundary should be established when Aluminum Oxide (Al2O3) chips are exposure exceeds 100 uGya/hr (10mR/hr) stimulated with green light The resulting blue light emitted from the RADIATION DETECTION AND MEASUREMENT Al2O3 is proportional to the amount of radiation exposure. The quantity of light Radiation detection apparatus should be emitted is equated to a radiation quantity capable of measuring radiation exposure expressed in 5mrem on the written report levels to 500 mGya/hr (50R/hr) returned to the user. MOBILE XRAY IMAGING Film Badge Exposure switch of such an imaging system consists of special radiation dosimetry film must allow the operator to remain at least packaged like dental film and enclosed in a 2m from x-ray tube during exposure special plastic holder GAS FILLED RADIATION DETECTOR Thermoluminescent Dosimeter Widely as a device to measure radiation contains crystalline chips of lithium fluoride intensity and to detect radioactive (LiF). contamination LiF absorbs and stores the energy (heat) o Ionization Chamber associated with exposure to ionizing o Proportional Counters radiation. 3mrem o Geiger-Muller Detectors Pocket Dosimeter IONIZATION CHAMBER Also known as pocket isolated chamber is Instrument of choice for measuring indicated when working with high radaiation intensity exposures or large quantities of radiation for Radiation levels 1mR/hr a short period of time, so that an immediate PROPORTIONAL COUNTERS reading is available to the user.. The pocket dosimeter, or pocket isolation Ability to distinguish between alpha and beta camber, resembles a penlight. Within the radiation dosimeter is a thimble ionization chamber. Laboratory equipments In the presence of ionizing radiation, a Assay of small quantity particular quantity of air will be ionized and es of radionuclides cause the fiber indicator to register radiation quantity in milliroentgen (mR). GEIGER-MULLER COUNTER Used for contamination control in nuclear medicine laboratories Limited to 100 mR/hr and portable xray imaging Survey for low radiation levels and radioactive contamination  CLUSTER 1 RTLE 2023 DOSE VS EXPOSURE QUALITY CONTROL Customary Unit International SI Designed to ensure that the radiologist is Quantity Name Symbol Name Symbol provided with an optimal image produced Rad Roentgen R Air kerma Gya during good imaging system performance Exposure – Deals with instrumentation and equipment Ionization of Periodic Monitoring air Acceptance testing, routine performance Absorbed Rad Rad Gray Gyt monitoring, and maintenance dose – By Medical physicist Received by the Patient SCHEDULED MAINTENNACE Effective Rem Rem Sievert Sv Dose – Dose Routine precodures that are performed received by usually weekly or monthly the PREVENTIVE MAINTENANCE personnel. Radiation Planned program of parts replacement at protection regular intervals purpose Replaced parts before it fails or unexpected Radioactivity Curie Ci Becquerel Bq downtime WHOLE BODY DL NONSCHEDULED MAINTENANCE 500 MsV/WK (50,000 mRem/wk) was recommended in 1902 Unexpected machine failure 1 mSv/wk current dl International Commision on RadPro (ICRO) COLLIMATION TEST annual whole-body DL – 20 mSv (2000 mrem) Misalignment must not exceed 2% of the SID Positive beam-limiting collimators (PBL) are PREGNANT RT automatic collimators that sense the size of the IR and adjust the collimating shutters to DL 0.5 that size DL for the fetus 5 mSv Should be provided with a second personal FILTRATION monitoring device positioned under the Most important patient proection protective apron at waist level characteristic of a radiographic imaging QUALITY ASSURANCE system QUALITY CONTROL Minimum total filrtation of 2.5 mm Al Evaluated annually QUALITY ASSURANCE FOCAL SPOT SIZE Monitors proper px scheduling, reception, preparation, and image interpretation Spatial resolution is determined by the focal Deals with people spot size of the xray tube Radiologist and imaging service Line-pair test tool to determine limiting management spatial frequency Evaluated annually or whenever an xray tube is replaced  CLUSTER 1 RTLE 2023 Three tools used for measurement of focal TEST FREQUENCY spot size: kVp Once in three year o Pinhole camera o Star pattern Timer Once in three mos o Slit camera Output, mR/mAs Monthly KVP CALIBRATION Inherent filtration Once in three mos Measured kVp should be within 10% of the indicated kVp Focal spot size Once in a year Evaluated annually or whenever high-viktage Central beam alignment Once in 2 mos generator components have change significantly Congruence of radiation and optical Once in 2 mos 4% kVp is necessary to affect imagae optical field density Grid alignment Annually and whenever film EXPOSURE TIME ACCURACY density appears non uniform Solid state radiation detectors are now used for exposure-timer checks Should be within 5% of the indicated time for exposure times greater than 10ms IMAGING SCIENCE AND INFORMATICS Accuracy of 20% is acceptable for exposure times of 10ms INFORMATION TECHNOLOGY EXPOSURE LINEARITY Use of computers to store, retrieve, transmit, and manipulate data or information Muust be within 10% for adjacent mA stations COMPUTER SCIENCE Determined by a precision radiation dosimeter that measures radiation intensity Widely used in medcine for the management at various combinations of mA and exposure of computer information management time system in hospital Can collect, transfer, process, and feed SCREEN FILM CONTACT medical information in time Should be evaluated once or twice a year INFORMATION SCIENCE Done by radiographing a wire mesh pattern and analyzing the image for areas of blur Interdisciplinary field primarily concerned with analysis, collection, classification, and retrieval of information Made of 2 components: o Practical – study of gathering, organizing, storing, and retrieving o Theoretical – metafield which anlyzes the processes and domains of information BIOMEDICINE Integral part of how health, illness, and individual identity are under