Ultrasound PDF

CLUSTER V RTLE 2023 ULTRASOUND Compression – High pressure, high density type of waves (crest) HISTORY OF ULTRASOUND...

CLUSTER V RTLE 2023 ULTRASOUND Compression – High pressure, high density type of waves (crest) HISTORY OF ULTRASOUND Transverse – Particles move in a 1918 – Sound navitagation and ranging was perpendicular direction to the direction of used the wave 1940 – Howry, Wild, and Ludwig showed o Propagation is perpendicular to that ultrasound waves generaeted by a the particle piezoelectric crystal transducer were ACOUSTIC VARIABLES: transmitted into the human body, the waves would return to the transducer from Period: Time taken for one complete cycle tissue interfaces of different acoustic to occur impedances Wavelength: Length of space over which 1947 – Dussick positioned two transducers one cycle occurs on opposite sides of the head to measure Amplitutde (depth): The maximum ultrasound transmission profiles displacement that occurs in an acoustic 1948 – Howry developed the first variable ultrasound scanner, consisting of cattle Frequency: Cycle per second (Hz) watering tank with a wooden rail anchored o High frequency, short wavelength, along the side lower penetration, better 1954 – Hertz and Edler developed resolution (lower attenuation can echocardiographic technique occur) 1970 – Gray scale static imaging and Real- Velocity: Frequency times wavelength time imaging Speed: can only determined by the medium 1980 – Doppler Technique Probe or Transducer: Sound source Ampltitude: Strength and intensity of sound SOUND waves (decibels, dB) A mechanical, longtiduinal wave PROPAGATION SPEED Cammot travel through a vacuum (no air) o Must travel to a Medium Speed at which soundwaves travel through a medium Speed of sound in a vacuum is 0 Depends on the medium ULTRASOUND Propagation speed and density is directly proportional High frequency sound waves above 20,000 o The denser the medium, the faster cycles per seconds (20kHz) (20Hz) the speed o Above 20Hz is inaudible to human o Audible sound: 16 Hz to 20000Hz MEDIUM SPEED (m/s) Air 330 o Infround: Below 16Hz Lung 300 – 1200 Used to scan tissues of the body Fat 1450 Ultrasound Pulse: 2-10 MHz Water 1480 Pulse duration: 1 microsecons Soft Tissue 1540 Pulse repetition: 1000 times/second Brain 1541 Liver 1550 LONGITUDINAL /COMPRESSION WAVES/ Kidney 1560 TRANSVERSE Blood 1570 Longitudinal – Particles that moves in the Muscle 1580 - 1600 same direction as the wave Bone 2,000-4,000 PZT (crystal) 3870  CLUSTER V RTLE 2023 INTERACTION OF SOUND AND MEDIUM Ex. Diaphragm, Bones, Fetal skull Attenuation: Weakening of soundwaves as DIFFUSE it travels through a medium Most surface are rough Absorption: When ultrasound energy is lost to tissue energy and converted into thermal Reflection: Beam redirected into multiple energy (heat) direction Reflection: Propagating siund energy strikes Ex. Liver, Pancreas, Spleen, Kidney, Muscle a boundary between two media and some SCATTERING returns to the source o Most important characteristic of Interaction with smaller reflector Utz Rayleigh scattering Remember: Reflection of an ultrasound wave Reflection: Only portion of soundwaves depends upon a difference in the acoustic return to source impedances at the boundary between the two media REFRACTION Occurs due to high difference between ACOUSTIC IMPEDANCE propagation speed Beam is deviated as it travels through a Product of tissue density with volecity of medium sound in the material Transmission with a bend When ultrasound beam encounter two Reflection: Bends or refract region with different impedances, the beam is reflected or absorb PIEZOELECTRIC CRYSTAL If two medium has a high impedance Piezein/Piezo means press or pressure difference, it has a high chance that the Present inside the transducer soundwaves will reflect back into the Crystalline materials composed of dipolar transducer molecules Describes how the particles of substance o Quartz – naturally occurring behave when subjected to pressure wave o Lead zirconate tinate – man made ceramic High density substance – high acoustic impedance When electricity reaches the Piezoelectric Low density substance – low acoustic impedance crystal, the crystal vibrates the atom which emits ultrasound pulse or Mechnical wave ACOUSTIC IMPEDANCE AND REFLECTION PIEZOELECTRIC EFFECT Same Acoustic impedance: 100% energy is transmitted. No Reflection Ability of the material to generate an Small Acoustic Difference: 95% energy is electric charge in response to applied transmitted, 5% reflected (echo) pressure Large Acoustic Difference: 1% energy is Production of “echo” transmitted, 99% reflected (echo) Conversion from mechanical energy into electric energy TYPES OF REFLECTION Inverse piezoelectric effect – Conversion SPECULAR from electrical energy into mechanical energy Reflection from a very smooth o Production of “pulse” reflector/medium Reflection: 90 degrees  CLUSTER V RTLE 2023 Small piezo Crystal dieameter – Increased beam Shortens the uts pulse length divergence Eliminates the vibrations from the back face Large piezo Crystal diameter – Decreased beam Controls length of vibrations from the front divergence face Improves axial resolution TRANSDUCER/PROBE ACOUSTIC LENS Device which converts one form of energy to another Reduce beam width of transducer o Electrical energy into uts Improve image resolution wave/mechanical Width of the beam: determines lateral Contains the PEC resolution Most expensive part of any ultrasound unit Lateral resolution: Ability to resolve structure across or perpendicular to the LINEAR ARRAY TRANSDUCER beam axis Parallel scan lines IMPEDANCE MATCHING LAYER Rectangular field of view Vascular, small parts and musculoskeletal Sandwich between the PEC and patient application Chosen to improved transmission into the Above 4 MHz body SECTOR/CURVILINEAR ARRAY TRANSDUCER BANDWIDTH Provides wide field of view Range of frequencies contained within an Most useful in abdominal and obstetric uts pulse scanning Wide BW: Best suited to image deep lying structures o Shorter spatial pulse length 3.5 MHz o Wider range of frequency o Vice versa sa narrow bitch CONVEZ TRANSDUCER ULTRASOUND BEAM Wide fan-shaped Useful for all parts of the body Area through which the sound energy o Except for specialized emitted from the ultrasound transducer echocardiography 3D and symmetrical around its central axis Beam intensity – measured in watts PHASED ARRAY TRANSDUCER NEAR FIELD – FAR FIELD Flat faced transducer Wide field of view FIELD ZONE FREQUENCY CRYSTAL Cardiac and cranial ultrasound INC. DEC. THIN THICK NEAR/FRESNEL LONG LESS DECREASE INCREASE PHYSICAL HOUSING FAR/FRAUNHOFER SHORT MORE INCREASE DECREASE Acts as electrical and acoustic insulator SIDE LOBES/GRATING LOBES Contains all individual component At various angles to the main beam ELECTRICAL CONNECTION Approx. 15% of the energy in the beam Made of thin film of gold or silver Cause a degradation of lateral resolution Formed in front and back of the crystal BACKING/DAMPING MATERIALS  CLUSTER V RTLE 2023 BEAM WIDTH CONTRAST RESOLUTION Dimension of the beam in the scan plane Ability of the imaging system of differentiate Affects the spatial resolution b/n body tissues and display them as Narrow beam width different shades of gray o Better spatial resolution Optimized by using the correct overall gain SLICE THICKNESS TEMPORAL RESOLUTION Three dimensional volume displayed as a Frame rate two dimensional image Imaging system to display events which occurs at different times as separated RESOLUTION images Ability of an imaging system to differentiate Higher frame rate: better temporal between structures resolution (vice versa) Spatial: Resolution in soace REAL TIME Contrast: Resolution of gray shades Temporal: Resolution in time Shows movement as it occurs SPATIAL RESOLUTION DOPPLER ULTRASOUND Detail resolution Demonstrates and measures blood flow Ability to display two structures situated DOPPLER EFFECT close together as separate image High frequency: Change in apparent frequency of a wave as a o Better resolution result of relative motion between observer o Lower penetrability and the source o High absorption Stationary reflector: reflected echoes are o Vice versa bitch the same as the transmitted wave Two components of spatial resolution Reflector that moves closer: reflected o Axial Resolution echoes are higher than transmitted echoes o Lateral resolution Reflector that moves away: reflected echoes are lower than transmitted echoes AXIAL RESL. CONTINUOUS WAVE DOOPLER Longitudinal, linear, depth of range Distinguish two objects parallel to the uts Ultrasound is continuous beam Measures high velocities accurately Depends upon spatial pulse length and No depth resolution wavelength Short spatial pulse: good axial resolution PULSED WAVE DOPPLER (vice versa) Utz is transmitted in pulse with good depth LATERAL RESL resolution Measures the speed of the blood in a Azimuthal, transverse, angular, or horizontal particular vessel Distinguish two objects perpendicular to the o Cannot measure high blood uts beam velocities in deep vessels Depends on beam diameter o High velocities may be wronly Smaller beam width: better lateral resl. (vice displayed as low velocities versa)  CLUSTER V RTLE 2023 COLOUR DOPPLER o Bone: higher absorption coefficient Increasing protein content gives increasing Shows different flow-velocities in different absorption colours REFLECTION DUPLEX DOPPLER SYSTEM Occurs when two large structure of Allows dobbler beam to be directed significantly different acoustic impedance accurately at any particular blood vessel form an interface WAVE PROPAGATION Occurs when a sound wave strikes an object that is larger than the wavelength Transmission and spread of ultrasound waves to different tissues SCATTERING o Average propagation for soft Occurs when an ultrasound wave strikes a tissues: 1540-4620m/s boundary or interface between two small WAVELENGTH structures Occurs when a sound wave strikes an object Length of single cycle of uts wave that is equal to or smaller than the Determines the resolution of scanner wavelength FOCUSING REFRACTION Adjustment of uts beam Occurs when the beam encounters an Improve resolution interface between two different tissues at an May be electronic or by a lens attached to oblique angle the transducer The beam will be deviated as it travels through the tissue AMPLIFICATION Occurs due to difference in wave velocity Done by the Time-gain-compensation (TGC) across an interface between two materials amplifier DIVERGENCE Compensate for uts attenuation in any part of body Occurs when the beam travels through o Improve quality of final image tissue and it will diverge due to diffraction effect ULTRASOUND INTERACTIONS AND ATTENUATIONS ULTRASOUND ARTIFACTS ATTENUATION A structure in an image which does not Decrease in the intensity and amplitude of directly correlate with actual tissue being the ultrasound waves as they pass through scanned tissues Unit: decibels per centimeter REVERBERATION FIVE MAIN PROCESSES THAT CAUSE ATTENUATIONS Comet tail Production of spurious or false echoes due ABSORPTION to repeated reflection between two Occurs when ultrasound enegy is lost to interfaces with a high acoustic impedance tissues by its conversion to heat mismatch Main factor causing attenuation Presence of two or more strong reflecting Higher Frequency: surface o Greater amount of absorption  CLUSTER V RTLE 2023 ACOUSTIC SHADOWING margins may be a good acoustic window to image the liver parenchyma. Caused by highly attenuating structure Anechoic – property of being free of Acoustic enhancement – caused by weakly echoes or with out echoes attenuating structures Angle of incidence – angle at which the EDGE SHADOWING ultrasound beam strikes an interface with respect to normal (perpendicular) Combination of refraction and reflection incidence occurring at the edges of rounded structures Ankle/Brachial Index (ABI) – ratio of ankle pressure to brachial pressure to provide a BEAM WIDTH ARTIFACT general guide to help determine the degree of disability of lower extremity. Variations of all echoes returning to the transducer Attenuation – weakening of the sound wave as it propagates through a medium SLICE THICKNESS ARTIFACT Axial resolution – ability to distinguish two structures along a path parallel to the Occurs due to the thickness of the beam sound beam Dependent upon beam angulation Inherent characteristic of transducer Biparietal diameter (BPD) – largest dimension of the fetal head perpendicular SIDE LOBE ARTIFACT to the midsagittal plane; measured by ultrasonic visualization and used to Echoes generated by side lobes assued by measure fetal development the transducer to have arisen from the central axis of the main lobe Color flow Doppler – velocity in each Appearance cangive rise to a false diagnosis direction is quantified by allocating a pixel Inherent characteristic of the transducer to each area; each velocity frequency change is allocated a color. MIRROR IMAGE ARTIFACT Complex – containing anechoic and Caused by specular reflection of the beam echogenic areas. at a large smooth interface Continuous wave ultrasound – wave in which cycles repeat indefinitely; consist of DOUBLE IMAGE ARTIFACT a separate transmit and receiver transducer housed within one assembly. Caused by refraction of the beam Coronal image plane – anatomic term EQUIPMENT GENERATED ARTIFACT used to describe a plane perpendicular to the sagittal and transverse plane of the Caused by incorrect use of the equipment body. control Detail resolution – includes axial and FUCKING DEFINITION OF FUCKING TERMS lateral resolution Doppler Effect – shift in frequency or Acoustic impedance – resistance of sound wavelength, depending on the conditions as it propagates through the medium of observation; caused by relative Acoustic window – ability of sonography motions among sources, receivers and to visualize a particular area. The full medium. urinary bladder is a good acoustic window Doppler ultrasound – application of to image the uterus and ovaries in trans- Doppler Effect to ultrasound to detect abdominal sonogram. The intercostal movement of reflecting boundary relative  CLUSTER V RTLE 2023 to the source, resulting in a change of the Homogeneous – having a uniform wavelength of the reflected wave composition Duplex imaging – combination of gray- Hyperechoic – producing more echoes scale real-time imaging and color or than normal spectral Hypoechoic – producing less echoes than Doppler Echo – reflection of acoustic normal energy received from scattering elements Intima – inner layer of the vessel; the or a specular reflector. middle layer is the media and the outer Echogenic – refers to a medium that layer is the adventitia. contains echo-producing structures. Iliopectineal line – bony ridge on the Embryo – term used for developing inner surface of ileum and pubic bones zygote through the 10th week of that divides the true and false pelvis gestation. Ischemia – area of the cardiac Endometrium – inner layer of uterine myocardium that has been damaged by canal disruption of the blood supply by the Endorectal transducer – high frequency coronary artery transducer that can be inserted into the Isoechoic – having a texture nearly as rectum and visualize the bladder and same as that of the surrounding prostate gland. parenchyma. Endovaginal transducer – high frequency Lateral resolution – ability to distinguish transducer (and decreased penetration) two structures lying perpendicular to the that can be inserted into the vagina to sound beam. obtain high resolution images of the Leiomyoma – most common benign pelvic structures. tumor of the uterine myometrium False pelvis – region above the pelvic brim Myometrium – thick layer of the uterine Fetus – term used for the developing wall embryo from the 11th gestational week Non-invasive technique – procedure that until birth. does not require the skin to be broken or Follicular cyst – functional or physiologic an organ or cavity to be entered ovulatory cyst consisting of an ovum Oblique plane – slanting direction or any surrounded by a layer of cells variation that is not starting at a right Frequency – number of cycles per unit, angle to any axis usually expressed in Hertz (Hz) or Parenchyma – functional tissue or cells of megahertz (MHz) a million cycles per an organ or gland seconds Piezoelectric effect – conversion of Gestational age – length of time pressure to electrical voltage or calculated from the first day of the last conversion of electrical voltage to menstrual period; also known as mechanical pressure gestational weeks Phasic flow – normal venous respiratory Gestational sac – fluid filled structure variations normally found in the uterus containing Porta hepatitis – region in hepatic hilum the pregnancy containing common duct, proper hepatic Gray scale – range of amplitude artery and main portal vein (brightness) between black and white Posterior acoustic enhancement – Heterogeneous – having a mixed increase in reflection amplitude from composition  CLUSTER V RTLE 2023 structure s that lie behind a weakly Sound wave – longitudinal waves of attenuating structure. mechanical energy propagated through a Posterior acoustic shadowing – reduction medium in reflection amplitude from reflectors Transducer/Probe – device that converts lying behind a strongly reflecting or energy from one form to another. attenuating structure. Transverse – plane that passes through Pulse wave ultrasound – a transducer the width of the body in a horizontal emits short pulses of ultrasound into the direction human body and receives reflection from Ultrasound – sound with a frequency the body before emitting another pulse of greater than 20 kHz (audible sound – 20 sound. kHz below) Real-time imaging – imaging with rapid Velocity of sound – speed with direction frame rate visualizing moving structures of motion specified or scan planes continuously HISTORICAL DEVELOPMENT Reflection – redirection (return) of a portion of the sound beam back to the 1940’s – Howry, Wild and Ludwig transducer independently showed that when Refraction – phenomenon of bending ultrasound waves generated by a wave fronts as the acoustic energy piezoelectric crystal transducer were propagates from the medium of one transmitted into the human body, these acoustic velocity waves would be returned to the Regurgitation – occurs when block leaks transducer from tissue interfaces of from one high pressure chamber to a different acoustic impedances. chamber of lower pressure 1947 – Dussick positioned two Resolution – measure the ability to transducers on opposite sides of the head display two closely spaced structures as to measure ultrasound transmission discrete targets profiles. Retroperitoneal cavity – area posterior to 1948 – Howry developed the first the peritoneal cavity that contains the ultrasound scanner, consisting of cattle aorta, inferior vena cava, pancreas, part watering tank with a wooden rail of the duodenum and colon, kidneys and anchored along the side. adrenal glands. 1954 – Hertz and Edler developed Retrouterine pouch – pelvic space located echocardiographic techniques anterior to the rectum and posterior to 1957 – Brown and Donald built early the uterus; also known as pouch of obstetric contact compound scanner Douglas Sagittal – plane that travels vertically from the top to the bottom of the body along the y axis Scattering – diffusion or redirection of sound in several directions encountering a particle suspension or rough surface Sonar (sound navigation and ranging) – instrument used to discover objects underwater and to show their location  CLUSTER V RTLE 2023 NUCLEAR MEDICINE DETECTION – A gamma camera or a scintillation camera transforms these Bracnh of science that uses radioactive emissions into images, providing physiologic material for diagnosis and therapy or pathophysiologic information Determine and diagnose based on the RECORDING – The camera records this organ or tissue function information in a computer or film Hal Anger – created gamma camera Georg Charles de Hevesy – father of nuclear TWO BRANCEHS OF NUCLEAR MEDICINE medicine THEARPEUTIC PROCEDURES TERMINOLOGIES: Treatmend of disease by means of TRACERS – radioactive drug/material that is radioactivity used in nucmed procedures Radionuclide therapy is used in the RADIONUCLIDE – radioactive atom or treatment of: nucleus; that has too many or few nucleons o Benign disease (e.g. RADIOPHARMACEUTICAL – trace a hyperthyroidism and arthritis) particular physiologic or pathology process o Malingnant disease (e.g. thyroid in the body cancer and hepatocellular o Radionuclide carcinoma) o Pharmacuetical Main radioisotope: I-131 NUCLEAR TRANSFORMATION – Process DIAGNOSTIC PROCEDURES when nucleus spontaneously emit particles to reach stability and transform itself to Using radioactive materials to test body another atom functions NUCLEAR MEDICINE PHYISICAN – Specialist Main radioisotopes: Tc-99m and F-18 with extensive education in the basic and clinical science of medicine who is licensed FORMS OF RADIONUCLIDES to use radioactive materials IN VITRO NUCLEAR MEDICINE TECHNOLOGIST – Perform the tests and is educated in the Analysis of samples theory and practice of nuclear medicine Ex. Detecting gamma-emitting radionucldies procedures in urine, feces PHYSICIST – Experienced in the technology IN VIVO of nuclear medicine and the care of the equipment, including computers Examination of the living body BASIC PROCEDURES OF NUCLEAR MEDICINE Commonly uses gamma camera to detect gamma-emitting radionucldies, introduced ADMINISTRATION – The tracer, or a to the body, most commonly by injection of pharmaceutical labeled with a radioactive a radiopharmaceutical substance is administered to the px NUCLEAR PHYSICS through: o Injection ATOM o Swallowing o Inhalation Fundamental building block of matter LOCALIZATION – The tracer will localize to Smallest part of an element that has all the specific organs or tissues properties of the element EMISSION – The tracer will emit gamma ray Nucleus – positively charged central part of emissions from the oran being studied the atom  CLUSTER V RTLE 2023 o Composes most of the mass of the o Repulsive foce – occurs between atom protons o Consist of nucleons, with varying o Nucleon binding force – holds an number of protons and neutrons atomic nucleus together Electron cloud – system of electrons CHEMICAL BONDING revolving around the nucleus in discrete energy levels Covalent Bond – chemical union b/n atoms formed by sharing one or more pairs of e- PARTICULATE RADIATION o Ex. H2O Possess suffificent kinetic energy Ionic Bond – bonding that occurs because of Capable of ionization an electrostatic force b/n ions Induces magnetic field o Ex. NaCI Has mass RADIONUCLIDES Considered matter Occupies space Unstable nuclides No wavelength Nuclides – species of atom, characterized by Loses its energy and intensity the nucleus ATOMIC STRUCUTRE RADIOACTIVITY Atom is essentially empty space Spontaneous emission of energy from Atom is neutral nucleus of unstable atoms The no. of protons determines the “chemical o Natural elements” o Artificial The closer an electron is to the nucleus, the NATURAL RADIOACTIVITY higher its binding energy If an atom has an extra electron or had an e- Exist in nature removed, it is Ionized Cosmic radioactivity; sun, stars, and moon o Ionized atom – carries a charged in Background radiation and altitude: both high magnitude to the difference b/n the number of e- and p+ ARTIFICAL RADIOACTIVITY ELECTRIFICATION Man-nade radiation Fall-out; nuclear ground testing When an atom or molecule gain or loses an Radiopharmaceuticals: nucmed e- it becomes an ion Devices: Teletherapy machine (Cobalt 60) Cation – lost an e-; positive charge o Smoke detectors (americium 241) Anion – gained an e-; negative charge PHYISICAL CHARACTERISTIC OF RADIOACTIVE ATOM BINDING ENERGY Decay disintegration or transformation Weak nuclear force – binds the atom constant Two forces acting on an electron Half-life t1/2 o Centripetal force – keeps the activity (A) or radioactivity electrons to its orbit o Centrifugal force – keeps the DECAY DISINTEGRATION electrons away from the nucleus A fraction or percentage of original number Two forces acting on an nucleus and of atoms decaying per unit minute protons WP: Determine the remaining activity of a certain radioactive atom after 3sec. if the  CLUSTER V RTLE 2023 original value or activity is 100mCi and given o PHYSICAL HALF LIFE transformation constant is 25% per sec o EFFECTIVE HALF LIFE Solution: Original amount = 100mCi, decay PHYSICAL HALF-LIFE by 25% per second 1st second: 25% of 100 (100-25 = 75mCi) Period of the time required to reach 50% of 2nd second: 25% of 75 (75-18.7 = 56mCi) the original atoms (acvitity of substance) 3rd second: 25% of 56 (56-14 = 42mCi) Time required for the activity of a radioactive Answer: 42mCi remaining activity after 3 material to decrease by one half due to seconds radioactive decay RADIAOCTIVE HALF-LIFE BIOLOGICAL HALF Radioisotopes disintegrate into stable Time required for the administered dosage isotopes of different elements at en ever to the body organ to reduce 50% of the value decreasing rate by regular process of Quantity of radioactive material never reach elimination/deliberation zero EFFECTIVE HALF-LIFE Measured in Ci RADIOACTIVE DECAY LAW The net effect of combination of the physical and biological half-lives in removing the Radioactivity reduces according to the radioactive material from the body natural physical law of exponential decay – a RADIOACTIVITY fixed percentage reduction occurs over a given period of time The time rate of decay of radioactive Describes the rate of radioactive decay and material curie (Ci) – old unit for the intensity quantity of the material present at any given of radioactivity Becquerel (Bq) – SI unit for time the intensity of radioacvitiy Expressed mathematically as: Where: o Activity remaining = initial activity x o 1 Ci = 3x1010.5n o ! Bq = 1 disintegration per second o N = number of half lives (dps) Process wherein the unstable atom (parent) Pertient convsersation laws apply during spiontaneously emits radiation to reach radioactive decay: more stable state (daughter) 1. Law of conservative of energy 2. Law of conservation of mass number PARENT DAUGHTER 3. Law of conservation of electric charge ORIGINAL NUCLEU RESULTING NUCLEI UNSTABLE NUCLEI STABLE NUCLEI TYPES OF TRANSITION EXCITED NUCLEI UNEXCITED NUCLEI EXCITED STATE GROUND STATE Isomeric Transition HIGHER ENERGY STATE LOWER ENERGY STATE o Involves the rearrangement of protons and neutrons to the lowest energy state and the emission of HALF-LIFE excess energy in the form of a Half-life t1/2 – period of time required for a gamma photon quantity of radioactivity to be reduced to ½ Isobaric Transition of its original alue o Involves nuclear transformation types: o BIOLOGICAL HALF-LIE  CLUSTER V RTLE 2023 MODES OF DECAY GAMMA DECAY Alpha emission decay Excess energy in the nucleus is being Beta Emission decay released in the form of gamma ray Electron capture Metastable state ISOMERIC TRANSITION No change in atomic number o Internal conversion Isomeric Transition o Gamma emission ALPHA DECAY/HELIUM NUCLEUS INTERNAL CONVERSION Proton and Neutron Rich Excited nucleus transfer its excess energy to Alpha particles - Most ionizing and an orbital e- (inner shell) destructive type, least penetrating e- to be ejected from atom (occurs when -2 proton and -2 neutron (A-4) the excess energy is greater than binding energy) BETA MINUS DECAY Result to: conversion e- Negatron Decay/Emission, Neutron Rich Filling of e- to inner shell vacancy = Emission of Negaton and an Anti-Neutrino characteristic x-ray and free e- Produced in Nuclear Reactors DECAY Mass Atomic Neutron 1 Neutron is converted into a positive and MODE No. No. (Z) No. (N) negative (A) Increase in Atomic number by 1 (Z+N) Isobaric Transition GAMMA SAME SAME SAME ISOMERIC DECAY BETA PLUS DECAY AND INTERNAL Positron Decay, Proton Rich CONVERSION One proton is converted to a neutron and a BETA MINUS SAME Z+1 N-1 positive electron called "Positron" BETA PLUS SAME Z-1 N+1 ISOBARIC ELECTRON SAME Z-1 N+1 Emission of Positron (Antimatter) and a CAPTURE Neutrino ALPHA A-4 Z-2 N-2 Produced in Cyclotron DECAY 1 positive is converted into a Neutron and a Is MERe GAMMA METASTABLE positron I SO BAR, BETA, and ELECTRON CAPTURED Decrease in atomic number by 1 ALPHA DECAYS by 4 Isobaric transition RADIOPHARMACEUTICALS ELECTRON CAPTURE/K CAPTURE DECAY Substance containing radionuclides suitable for administration to humans for diagnosis Positron Rich Nucleus or treatment of disease Proton is converted into a Nuetron Gamma radiation emitted from these drug Produced in Characteristic X-rays from the molecules readily penetrates the tissues and K-shell escapes from the body, thus allowing positive is converted into a neutron external detection and measurement For image formation: Radionuclides must be Decrease in atomic number by 1 gamma emitters Isobaric Transition o Must not emit alpha or beta particles  CLUSTER V RTLE 2023 Portrays a body system without disturbing o Ibiturmomab fluxetan - its function Localization of tumor o Physiology o Octreoscan – Neuroendocrine o Biochemistry tumors o Pathology o ProstaScint – Prostate cancer o Oxine – WBC/abscess imagimg RADIOLABELING/TAGGING IODINE (121I) Process of making radiopharmaceuticals o Radioactive molecule 13.3hr o Biologically active molecule CF: Sodium Iodide (same for 131) Main medical isotopes used for diagnosis o Human serum albumin o Tc99m, F18 Diagnostic: Sodium Iodide – Thyroid function Main Medical isotope used for therapy o Human serum Albumin – Plasma o Ioidine-131 volume IMAGING RADIOPHARMACEUTICALS IDOINE (131I) CHROMIUM (51Cr) 8 days 27.8 Days CF: Hippurate CF: Sodium Chromate Albumin Diagnostic: Renal function Diagnostic: RBC volume and survival NITROGEN (13N) COBALT (57Co) 10 min 270 Days CF: Ammonia CF: Cyanocobalamin (Vitamin B12) Diagnostic: Mycoardial perfusion Diagnostic: Vitamin B12 Absorption RIBIDIUM (82Rb) FLUORINE (18F) 75 sec 110 min CF: Rbidium Chlroide CF: Fluorodeoxyglucose Diagnostic: Cardiovascular imaging Diagnostic: Oncology and Myocardial TECHNETIUM (99Tc) hibernation 6HR GALLIUM (67Ga) Chemical form and Diagnostic: 77hr Sodium Pertechnetate – Imaging of brain, CF: Gallium Citrate thyroid, scrotum, salivary glands, renal Diagnostic: Inflammatory process and tumor perfusion, and pericardial effusion imaging Sulfur colloid – Imaging of liver, spleen, renal transplant, and lymphoscintigraphy INDIUM (111In) Macroaggregated albumin – Lung imaging 67.4hr Sestamibi – Cardiovascular imaging, myocardial perfusion CF: DTPA o Ibritumomab Fluxetan DTPA – Brain and renal imaging o Ostreoscan (pentetreotide_ DMSA and MAG3 – renal imaging o ProstaScint (capromab penedetide) Diphosphonate – Bone imaging o Oxine Pryophospate – Bone and myocardial Diagnostic: DTPA – Cerebrospinal fluid imaging imaging RBC – Cardiac function imaging  CLUSTER V RTLE 2023 HMPAO – functional brain imaging wnd WBC BIOLOGICALLY ACTIVE MOLECULE abscess imaging Acts as the tracer/carrier, and determines Iminodiacetic derivation – liver function localization and biodistribution imaging Determines the beheavior of the radpharma Myobiew (trtrofosmi) and Cardiolite in the body (sestamibi) – Myocardial perfusion Body functions may be performed by the THAILUM (201Ti) radioactive isotope o Ex. I-123 in thyroid imaging or the 73.5 hr isotope may need to be cchemically CF: Thallous chloride bound to a pharmaceutical Diagnostic: Myocardial imaging o Ex. Tc-99m HDP for bone scans XENON (133Xe) SOURCE OF RADIONUCLIDES 5.3 days REACTORS CF: Xenon gas Diagnostic: Lung ventilation imaging Uses neutron activation – adds neutrons to stable atoms THERAPEUTIC PHARMACEUTICALS Radionuclides produced will generally decay by a beta minus process Also used for the treatment of number of Ex. Fission of Nuclear Fuel disease o I-131, Mo-99, &-97 (Cs-137, Co-60) Goal is to deliver a sufficiently large dose to the target organ, tissue, or cell type while ACCELERATORS All currentl approved therapeutic radpharmaceutical emits beta particles Adds charged particles (protons, deuterons) Commonly used therapetuc radpharma to stable nuclides include: Cyclotron – accelerated particle enter sinto o Iodine 131 Nal for hyperthyroidism nucleus and thyroid cancer Radionucldies produced will generally decay o Sr-89 chloride and Sm-153 by a beta minus process lexidronam for relief of pain from o Gamma emitters – Ga67, I123, cancer metastatic to bone In111, Co57 o 1odine 131 and Y-90 label o Positron emmiters – 18F monoclonal antibodies for treatment of certain non-Hodgkin’s lymphomas GENERATORS P-32 as sodium phosphate for bone marrow Produces radionuclides that are short lived disorders such as polycythemia vera Useful radionuclides (daughter) is continuously produced by the radioadctive MAIN COMPONENT OF RADPHARMA decay of a longer lived (parent) radionuclides RADIOACTIVE MOLECULE Ex. 99mTc, 81mKr Allows the monitoring of distribution PREPARATION OF RADPHARMACEUTICALS Permits external detection from the body by Prepared at department of NM by a radionulide imaging device (gamma radiopharmacist camera, SPECT, PET) or from a body fluid At room temperature, by heating in (body plasma, urine) waterbath  CLUSTER V RTLE 2023 All 99mTc preparation o Agent should rapidly and specifically localize IDEAL RADIOPHARMACEUTICAL o Acoords to the intended application IDEAL PHARMACEUTICAL IDEAL RADIONUCLIDE RADIONUCLIDE GENERATORS Short biological half-life Short physical half-life Minimal/No side effects Pure Gamma emitter Solution to the problem of supply of short Easy to prepare lived radionuclides (ex., Tc99m, Rb82) LLabelling Stability Principle: Parent nuclides with relatively long Localization is fast and precise Energy 100-200keV half-life, upon decay, produces daughter nuclei with shorter half-life Should not alter physiological Readily available system under examination ELUTION Suitable for incorporation into a Process of removing “daughter” pharmaceutical raduinuclide o No removal of “parent radionuclide” o Elution is a sterile procedure DESIGN CHARACTERISTICS OF Techniques: RADIOPHARMACEUTICALS o Precipitation Decay in gamma emissions o Distillation o Suitable energy: 100-300 keV is o Ion excahnge ideal for gamma cameras TECHNETIUM-99M o Suifficient abundance of emission for detection Most commonly used radionuclide Have no particulate emissions/radiation due o Readily available to o Favorable energy o Increases px rad dose o Monoenergetic gamma photon o Does not add diagnostic (140 keV) information o Favorable dosimetry with lack of Beta emissions are only suitable for primary particulate radiations therapeutic radiopharmaceuticals o Ideal half-life (6 hrs) for many Optimal effective half life clinical imaging studies o Long enough for the intended application TC-99M VS TC-99 o Usually a few hours TC-99M o High specific activity o To avoid any toxic effect to the Half life is 6hrs patient Only emits gamma electromagnetic o Tc99m radiation o Compatible pharmaceutical Decay product of Mo99 through isobaric component transition o Free of any toxicity TC-99 o Free of secondary/side effects o Readily available Half-life is 211,000 yrs o Easily compounded Emits beta particulate radiation o Reasonable cost Decay product of U-335 through fission o Fast and precise localization  CLUSTER V RTLE 2023 FORMS OF TECHNETIUM-99M o Diethylenetriamine-pentaacetic acid (DTPA) – renal dynamic scintigraphy, lung Tc99m Pertechnetate (99mTcO-4) ventilation( (aerosol). Glomerulal filtration Behaves similarly to Iodine rate To Diagnose Meckel’s diverticulum o Mercaptoacetyltriglycine (MAG3) – renal Used for thyroid, salivary gland, and stomach dynamic scintigraphy imaging o Dimercaptosuccinic acid (DMSA) – renal cortical scintigraphy Tc99m Macroaggregated Albumin (Tc-99m MAA) o Iminodiacetic acid (HIDA) – hepatobiliaryscintigraphy Used for lung imaging o Sestamibi (cardiolite) – Myocardial Trapped in the capillary of the lung perfusion scintigraphy, breast imaging The albumin macroaggregates – 15-17um in o Tetrofosmin (Myoview) – Myocardial size perfusion scintigraphy Biological half life in the lung: 8-12 hrs o Exametazine (HMPAO) -Cerebral perfusion Tc99m Human Serum Albumin scintigraphy, WBC labeling o Bicisate (ECD) – cerebral perfusion Blood pool imaging such as heart or placenta scintigraphy Retained in the plasma for a long period of NON-Tc99M RADIOPHARMACEUTICALS FOR SINGLE- time PHOTON IMAGING RADIOLABELING WITH Tc99m Xe-133 (inert gas) – pulmonary ventilation Cold kits scintigraphy Pre-packed set of sterile ingredients Xe-127 xenon (inert gas) – pukmonary designed for the preparation of a specific ventilation scintigraphy radiopharmaceutical Kr-81m krypton (inert gas) – pulmonary ventilation scintigraphy Typical ingredients: I-123 sodium Iodide – thyroid scintigraphy, Compouund to be complexed to the Tc99m thyroid uptake function studies e.g. Methylene diphosphonate (MDP) In-111 oxine leukocytes – inflammatory Stannous Ions (sn+) disease and infection detection Stabilizers, Buffers, Antioxidants, I-123 meta-iodo-benzyl-guanidine (MIBG) – Bactericides adrenal medullary tumor imaging In-111 penetreotide (OctreoScan) – Tc99M-PHARMACEUTICALS Somatostatin receptor tumor imaging o Sodium Pertechnetate – Meckels I-123 ioflupane (DatScan) – Dopamine diverticulum detection, salivary, and thyroid transporter receptor imaging for Parkinson gland scintigraphy disease and parkinsonian syndromes o Sulfur colloid – Luymphoscintigraphy THERAPEUTIC RADIOPHARMACEUTICALS Liver/spleen scintigraphy, bone marrow scintigraphy 1-131 sodium iodide – thyroid cancer o Diphosphonate – skeletal scintigraphy scintigraphy; thyroid uptake function o Macroaggregated albumin (MAA) – studies; treatment of Graves disease toxic Pulmonary perfusion scintigraphy, liver nodule and thyroid cancer intraarterial perfusion scintigraphy I-131 tositumomab (Bexxar) – B-cell o RBC – radionuclide ventriculography, lymphoma imaging and therapy gastrointestinal bleeding, hepatic In-111 ibritumomab (Zevalin) – B-cell hemangioma lymphoma therapy  CLUSTER V RTLE 2023 Some radionuclides emit particulate radiation such as beta particle which can be used to directly destroy or ablate malignant disease processes PET RADIOPHARMACEUTICALS PERFUSION TUMOR BLOOD METABOLIC RECEPTOR AMYLOID BINDING O-15 Water F-18 C-11 Carbon F-18 sodium C-11 carfentanil F-18 Florbetapir Fluordeoxyglucose monoxide fkuoride N-13 C-11 Methionine Ga-88 Fe-18 C-11 Raclopride Ammonia Ethylenediamine Fluorodeoxygluc tetraacetic acid ose Rb-82 F-18 O-15 Oxugen F-18 fluoro-I-dopa Chloride Fluorothymidine C-11 Acetate C-11 Palmitate N-13 Glutamate CYCLOTRON AND PET ISOTOPES Most pet isotopes are produced in cyclotrons F-18, C-11. O-15 o Positron emitters have “too many: protons for stability o Normally produced by smashing protons into stable targets o To make F-18, fire protons into O- 18 enriched water  CLUSTER V RTLE 2023 FACTORS AFFECTING THE DOSE ORGAN VISUALIZATION Aadministered activity Hot spot –localize in abnormal areas Diagnostic reference levels (ARSAC) showing areas of increased uptake /hot Effective half-life areas Bio-Distribution o Ex. Bone scanning and brain Radiochemical purity scanning Pathology Cold spot – Localize in normal tissues of an Drugs organ with abnormal areas showing areas Type of radioactive decay of absent activity / cold areas Energy of emission o Ex. Thyroid scanning and liver scanning METASTABLE RADIONUCLIDE TYPE OF DETECTORS Electron of excited atoms are in higher energy state thus must emit the excess GAS FILLED DETECTORS energy in order to go a lower energy state Depend on ionization in which ionization is The time it takes for that to happen is 10^-8 translated into electric current or impulses sec Radiation is sensed by detecting ionization of If the time it takes is much longer than 10^- gas molecules produced by deposition of 3sec, the atom is said to be metastable energy during radiation’s passage MECHANISMS OF RADPHARMA LOCALIZATION Ionization chamber – gas-filled chamber with positive and negative electrodes COMPARTMENT LOCALIZATION – Blood Proportional counters – greater applied pool imaging, direct cystography voltage between electrodes rather than in PASSIVE DIFFUSION (CONCENTRATION the Ionizaion chamber DEPENDENT) – Blood-brain barrier breakdown, glomerular filtration, GAS AMPLIFICATION IN PROPORTIONAL CHAMBER cisternogaraphy Phenomenon where a higher voltage results CAPILLARY BLOCKADE (PHYSICAL in secondary ionization in the sensitive ENTRAPMENT) – Perfusion imaging of lungs volume of the chamber PHYSICAL LEAKAGE FROMA LUMINAL – Increased ionization by a factor of 1,00 to Compartment GI bleeding, detection of 1,000.000 urinary tract or biliary system leakage Proportional to the energy originally METABOLISM – Glucose, fatty acids deposited in the gas chamber CHEMICAL BONDING AND ABSORPTION – Proportional chambers do not have wide Skeletal imaging application in clinical nucmed. They are used CELL SEQUESTRATION – Splenic imaging in research to detect alpha and beta particles (heat-damaged RBC), WBC RECEPTOR BINDING AND STORAGE – GEIGER MULLER Adrenal medullary imaging, somatostatin Voltage is increased even higher than in the receptor imaging proportional chamber application PHAGOCYTOSIS - Reticuloendothelial All the molecules of the gas are ionized, system imaging liberating a large number of e-. This results o Antigen-antibody tumor imaging in a large e- pulse and detection of single ACTIVE TRANSPORT (ACTIVE CEULLULAR event but not their energy UPTAKE)- Hepatobiliary imaging, renal Used for contamination control in nuclear tubular function, thyroid and adrenal medicine laboratories imaging  CLUSTER V RTLE 2023 Survey meter is one of the example of GM TYPES OF COLLIMATOR counter Parallel Hole collimator SCINTILLATION DETECTORS Most common used collimator Depends on excitation Consist of large number of small hole, When ionization particles pass through separated by the lead sepia which are certain crystals, it flashes light or scintillation parallel to each other is emitted Usually perpendicular to the crystal Most commonly used type in nuclear Geometric efficiency is affected by; medicine o Shape of collimator holes Used to measure the energy distribution of o Length of collimator holes parotciles in addition to counting them o Diameter of collimator holes High sensitivity to gamma rays. Used for CONVERGING COLLIMATOR – Holes are not detecting low level of activity parallel but are angled to converge to a focal point, providing some magnification GAMMA CAMERA (ANGER SCINTILLATION CAMERA) DIVERGING COLLIMATOR – Opposite of Invented by Hal Anger in 1898 converging collimator, holes are angled Most commonly used instrument in Nuclear opposite to the direction in convering medicine collimator which make image smaller Consists of: PINHOLE COLLIMATOR – Thick conical o Collimator collimators with a single 2-5 mm hole in the o Crystal Sodium iodide bottom center. As a source is moved away o Photomultiplier tune from the surface of a pinhole collimator, the o Pulse/heigh analyzer camera gets smaller o Scaler/timer FAN BEAM COLLIMATOR – Combiantion of o CRT parallel hole collimator (along one axis) and Function: provide an image of radionuclide a converging collimator (along other axis) injected to the px PHOTOMULTIPLIER TUBE (PMT) o Dects the gamma ray and determines its location and its Onverts the light from the crystal into an energy in which is further electrical pulse which contain series of processed by electronic in the dynodes console before displayed on CRT Optically coupled to the crystal through a screen for exposing light guide or simple glass window For every 7-10 light photons, one electron is COLLIMATOR ejected by photoelectric effect. Electron Used to limit the angle of entry of radiation produced are acceleraeted towards the first Determine to a large extend the final image dynode. quality obtained from the gamma camera o For each dynode, number of e- is and are therefore one of the most important multiplied by a factor of 3-4 part of the gamma camera Size of the electrical signal from the PMT depends on the following: o Total number of light photons which reach the cathode depending on the gamma ray energy o Light voltage applied to PMT  CLUSTER V RTLE 2023 POSITRON EMISSION TOMOGRAPHY (PET) C0MPUTED TOMOGRAPHY Cross sectional tomographic section of the Form of tomography made possible by the body with a rotating fan beam, a detector positrons array, and computed reconstruction Positron undergo annihilation by combining Other names: Computed Aaxial Tomography the e-, two 511 keV gamma rays are given off (CAT), Computed Transaxial Tomography in opposite direction 180deg apart (CTAT), Computed Reconstruction Density and effective number of Nal (Ti) Tomography (CRT), Digital Axial Tomography crystals are not ideal for detecting 511 keV (DAT), Body section Roentgenography gamma rays used in PET imaging Bismuth germinate oxide (BH0) is CT SCANNER approximately twoce as dense with an Consist of xray source emitting finely effective z of74, compared with an effective collimated xray beam and a single detector z of 50 for Nai (TI) both moving synchronously in a translate or o BG0 is extensively used in PET rotate mode or a combination of both imaging applications for this Computer – uses binary system reasons for early generation o Modern PET scanners used Binary digit/bit – code for 2 values or 2 detectors made of Lutetium shades of gray which corresponds to white oxyorthoscilicate (LSO) or and black Gadolinium oxyorthosiclicate o 8 bits = 1 byte (GSO) o 2 bytes = 1 word o Lutetium yttrium oxyorthosilicate o 16 bits = 1 word (LYSO) is also used, which is LSO HISTORY doped with a small amount of yttrium ALLESANDRO VALLEBONA (1930) – Thick detectors – efficiently detects 511-keV represent a single slice of the body on annihilation photons radiographi film (topography) GODFREY HOUNSFIELD (1970) – First PET PHYSICS demonstrated the CT technique. PET Camera contains ring of detectors o Godfrey – father of CT scan imaging (scinitllators) surrounding the patient 1979 – Hoounsefield and Allan Mcleod Detectors are coupled to PMT to detect light Cormack shared the Nobel prize in physics produced in each detector 1980 – CT scan machine became widely available EMI SCANNER 1ST CT SCAN AMCHINE 180 translation/1deg rotation Acta – 1st CT system that could make images of any part of the bidy CONVENTIONAL/AXIAL TOMOGRAPHY Plane of the image is parallel to the long axis of the body Produces sagittal and coronal images COMPUTED TOMOGRAPHY  CLUSTER V RTLE 2023 Plane of image is perpendicular to the long Imaging time: 120 kvP, 400mA Photodiode: converts light into electrical High speed rotors: for heat dissipation signal o Anode head capacity: 7 MHU (Spiral CT) o Does not required power supply Heat Storage capacity: 8 MHU Anode cooling rates: 1MHU/min THREE IMPORTANT FACTORS CONTRIBUTING TO Small focal spot DETECTOR EFFICIENCY o Due to high spatial resolution GEOMETRIC EFFICIENCY imaging Tube life: 5000 exposures (Conventional CT) The area of the detectors sensitive to radiation as a fraction of the total exposed DETECTOR ARRAY area Entire collection of detectors The amount of space occupied by the Image receptor in CT detector collimator plates relative to the surface area of the detector Detector: absorbs radiation and converts it to electrical signal QUANTUM EFFICIENCY High detector efficiency – ability of detector to capure transmitted photons and change The fraction of incident x-rays on the them to electronic signal detector that are absorbed and contribute to Hgih scatter suppression the measured signal High stability – allows a system to be used CONVERSION EFFICIENCY without interruption of frequent calibration The ability to accurately convert absorbed TYPES: xray signal to electrical signal Gas-filled detectors – previously used OVERALL/DOSE EFFICIENCY Scintillation and SSD – recently used The product of geometric, quantum and GAS DETECTOR conversion efficiency Ionization of gas The product of the following factors: Three types: o Stopping power of the detector o Ionization chamber material o Proportional counter o Scintillator efficiency (in solid-state o Geiger-Muller counter types) Characteristics: o Charge collection efficiency (in o Excellent stability xenon types) o Large dynamic range o Geometric efficiency o Low quantum efficiency o Scatter rejection Normal value: b/n 0.45-0.85 SCINTILLATION DETECTOR Value: