ARMRIT STUDY GUIDE PACKET WITH COMPLETE SOLUTION

ATOMS - Answer FUNDAMENTAL SUBMICROSCOPIC UNIT OF ALL MASS. SIZE OF THE ATOM AND ITS WEIGHT HAVE INTERESTED SCIENTISTS FOR A LONG PERIOD. SUBSEQUENTLY, EXPERIMENTS WERE DEVISED TO DETERMINE THE SIZE AND WEIGHT OF THE VARIOUS ATOMS. THE LIGHTEST OF ALL ATOMS IS HYDROGEN. PROTON - Answer A SUBATOMIC PARTICLE HAVING A POSITVIE CHARGE IDENTICAL IN MAGNITUDE TO THE NEGATIVE CHARGE OF AN ELECTRON AND, TOGETHER WITH THE NEUTRON, A COMPONENT OF ALL ATOMIC NUCLEI. THE PROTON FORMS, BY ITSLEF, THE NUCLEUS OF THE HYDROGEN ATOM. THE MASS OF A PROTON IS APPROXIMATELY 1836 TIMES THAT OF AN ELECTRON AND THE MASS OF AN ATOM IS CONTAINED ALMOST ENTIRELY IN THE NUCLEUS. THE PROTON HAS AN INTRINSIC ANGULAR MOMENTUM OR SPIN AND THUS A MAGNETIC MOMENT (VERY SMALL MAGNETIC FIELD). THE NUMBER OF PROTONS IN THE NUCLEUS OF AN ATOM DETERMINES WHAT ELEMENT IT IS; THE ATOMIC NUMBER OF AN ELEMENT DENOTES THE NUMBER OF PROTONS IN THE NUCLEUS. ELECTRON - Answer A SUBATOMIC MPARTICLE THAT, ALONG WITH PROTONS AND NEUTRONS, MAKE UP THE ATOMS THE FLOW OF AN ELECTRIC CURRENT IN A CONDUCTOR IS CAUSED BY THE DRIFTING OF FREE ELECTRONS IN THE CONDUCTOR. HEAT CONDUCTION IS ALSO PRIMARILY A PHENOMENON OF ELECTRON ACTIVITY. THE CHARGE OF THE ELECTRON IS THE BASIC UNIT OF ELECTRICITY. ELECTRONS HAVE HALF-INTEGRAL SPIN; SPIN IS A PROPERTY OF SUBATOMIC PARTICLES THAT INDICATES THE PARTICLE'S ANGULAR MOMENTUM. NEUTRON - Answer A SUBATOMIC PARTICLE THAT IS NEUTRAL THEREFORE HAS NO CHARGE. IT IS LOCATED IN THE NUCLEUS AND SERVES AS A STABILIZER. THE MASS OF A NEUTRON IS SLIGHTLY GREATER THAN THE PROTON MASS AND HAS AN ENORMOUS EFFECT ON THE QUANTUM SPIN VALUE OF AN ELEMENT. THE NET CHARGE ON A NEUTRON IS 0 MAGNETISM - Answer IS DESCRIED AS THE ABILITY OF A SUBSTANCE TO ATTRACT IRON, COBALT AND NICKEL. IT IS THE POWER OR FORCE CREATED BY A SUBSTANCE HAVING THE PROPERTY OF CREATING OR INDUCING MAGNETIC DIPOLES. THE MAGNETIC FIELD OF ANY MAGNET HAS A DIRECTION, SIGNIFIED NORTH AND SOUTH. THIS PROPERTY OF A MAGNET MAKES IT A DIPOLE. DIPOLE - A MAGNETIC FIELD CHARACTERIZED BY ITS OWN MAGNETIC NORTH AND SOUTH POLES SEPARATED BY A FINITE DISTANCE. MAGNETIC SUSCEPTIBILITY - Answer DEFINED AS THE TENDENCY OF A SUBSTANCE TO ATTRACT OR REPEL MAGNETIC LINES OF FORCE DEPENDENT ON THE MAGNETIC PROPERTIES OF ITS ELECTRONS. DIAMAGNETIC - Answer THE PROPERTY OF MOST SUBSTANCES WITH PAIRED ORBITAL ELECTRONS THAT HAVE OPPOSITE SPINNING AND THEIR MAGNETIC MOENTS CANCEL EACH OTHER OUT. SUBSTANCES WITH DIAMAGNETIC SUSCEPTIBILITY WEAKLY ATTRACT OR REPEL MAGNETIC LINES OF FORCE. MAGNETIC SUSCEPTIBILITY OF MOST HUMAN BODY TISSUES ARE DESCRIBED AS DIAMAGNETIC. PARAMAGNETIC - Answer THE PROPERTY OF SUBSTANCES WITH POSITIVE MAGNETIC SUSCEPTIBILITY THAT ATTRACT AND REPEL MAGNETIC LINES OF FORCE. THESE SUBSTANCES (GADOLINIUM, METHEMOGLOBIN, FREE RADICALS) CONTAIN ONE OR MORE UNPAIRED ORBITAL ELECTRONS AND PRODUCE MARKED REDUCTIONS IN THE T1 AND T2 RELAXATION TIMES. UNPAIRED ORBITAL ELECTRONS SPIN IN THE SAME DIRECTION AND HAVE THE TENDENCY TO LINE UP WITH THE MAGNETIC FIELD. THEREFORE PRODUCING ADDITIONAL MAGNETIC FIELDS. SUPER-PARAMAGNETIC - Answer THE PROPERTY OF SUBSTANCES WITH LARGE POSITIVE MAGNETIC SUSCEPTIBILITY WHICH STRONGLY ATTRACT OR REPEL MAGNETIC LINE SOF FORCE. THESE SUBSTANCES (HEMOSIDERIN AND SUPERPARAMAGNETIC IRON OXIDE -SPIO) HAVE A SINGLE MAGNETIC DOMAIN AND ARE MAGNETIZED IN A MAGNETIC FIELD. THEIR MAGNETIC SUSCEPTIBILITIES ARE MUCH LARGER THAN THOSE OF PARAMAGNETIC SUBSTANCES AND SIMILAR TO THOSE OF FERROMAGNETIC MATERIALS. UNLIKE FERROMAGNETIC SUBSTANCES, SUPERPARAMAGNETIC MATERIALS DO NOT EXHIBIT RESIDUAL MAGNETISM WHEN THE EXTERNAL FIELD IS REMOVED. FERROMAGNETIC - Answer THE PROPERTY OF SUBSTANCES WITH LARGE POSITIVE MAGNETIC SUSCEPTIBILITY THAT BECOME MAGNETIZED WITHIN A MAGNETIC FIELD AND REMAIN MAGNETIZED AGTER BEING REMOVED FROM THE MAGNETIC FIELD. FERROMAGNETIC SUBSTANCES INCLUDE A NUMBER OF IRON AN COBALT-CONTAINING METALS. MAGNETIC FIELD - Answer A VECTOR QUANTITIY CONSISTING OF BOTH A NORTH AND SOUTH POLE; IT EXERTS AN INDUCTION FORCE ON FERROMAGNETIC AND PARAMAGNETIC SUBSTANCES. WHEN SYMBOLIZING THE FLOW AND AREA OF A MAGNETIC FIELD, SPECIAL LINES ARE USED; THEY ARE FIELD OR FLUX LINES FIELD OR FLUX LINES - Answer MEASURE THE FLOW AND AREA OF A MAGNETIC FIELD. THE STRONGEST AREA OF THE MAGNETIC FIELD IS WHERE THE FIELD OR FLUX LINES CONVERGE AND IS CALLED THE ISOCENTER. AWAY FROM THE ISOCENTER THE FIELD OR FLIX LINES REPRESENT THE FRINGE FIELDS. ISOCENTER - Answer AREA OF THE MAGNETIC FIELD WHERE THE FIELD STRENGTH IS THE GREATEST, IN MRI THE CENTER OF THE SCAN AREA FRINGE FIELDS - Answer WEAKER MAGNETIC FIELDS THAT ARE AWAY FROM THE ISOCENTER, IN MRI OUTSIDE OF THE SCANNING AREA. FLUX - Answer FLOW OF ENERGY; MAGNETIC FIELD FLOWING FROM NORTH TO SOUTH POLES REPRESENTED BY MAGNETIC LINES OF FORCE. FORCE - Answer THE ABILITY TO CREATE WORK OR CHANGE (MEASURED IN HORSEPOWER). WHEN DESCRIBING THE STRENGTH OF AN MRI MAIN MAGNETIC FIELD, THE SI UNIT MOST COMMONLY USED IS TESLA. A SYMBOL TO DESCRIBE THE DIRECTION AND STRENGTH OF A MAGNETIC FIELD IS CALLED VECTOR. VECTOR - Answer A MATHEMATICAL ENTITIY CHARACTERIZED BY STRENGTH (MAGNITUDE) AND DIRECTION. VECTOR QUANTITIES CAN BE ADDED OR SUBTRACTED FROM ON ANOTHER. VECTORS WITH THE SAME DIRECTION - ADD UP; OPPOSITE DIRECTION - CANCEL EACH OTHER OUT. THE SYMBOL USED TO DESCRIBE THE STATIC (MAIN) MAGNETIC FIELD AND ITS VECTOR IS BO. HOMOGENEITY - Answer TERM USED TO DESCRIBE MAGNETIC UNIFORMITY IN THE LARGE STATIC MAGNETIC FIELD IS HOMOGENEITY. THE SPECIFICATION THAT IS ACCEPTABLE FOR FIELD HOMOGENEITY OF AN MRI MAGNET FOR CLINICAL SCANNING IS 20-30 PP M FARADAY'S LAW - Answer IN A LOOP OF CONDUCTOR WHERE AN ELECTRIC CURRENT IS INTRODUCED AND MAINTAINED, A MAGNETIC FIELD WILL BE PRODUCED IN THE CENTER. THIS IS ALSO TRUE INVERSELY. FLEMINGS RIGHT HAND RULE - Answer IF THE ELECTRON FLOW IS IN THE DIRECTION OF THE CURLED FINGERS, THE THUMB WILL POINT IN THE DIRECTION OF ITS MAGNETIC NORTH POLE. FLEMING'S RIGHT HAND, THUMB UP RULE - Answer SHOWS NORTH AND SOUTH POLSES OF MAGNET. IF TH ELECTRON FLOW IS THE COUNTER CLOCKWISE DIRECTION, THE THUMB WILL POINT IN THE DIRECTION OF ITS MAGNETIC NORTH POLE. IF THE ELECTRON FLOW IS IN THE CLOCKWISE DIRECTION, THE THUMB WILL PONT IN THE DIRECTION OF ITS MAGNETIC SOUTH POLE. ELECTROMAGNETIC ENERGY (EME) - Answer ELECTROMAGNETIC ENERGY IS AN ELECTRIC AND MAGNETIC DISTURBANCE THAT TRAVELS THROUGH SPACE AT THE SPEED OF LIGHT, SYMBOLIZED BY ASINE WAVE THAT HAS TWO COMPONENTS OF MEASUREMENT, WAVELENGTH AND FREQUENCY. SINE WAVE - Answer SYMBOL USED TO ILLUSTRATE WAVE LENGTH AND FREQUENCY OF ELECTROMAGNETIC ENERGY FREQUENCY - Answer THE NUMBER OF REPETITIONS OF RHYTHMIC (SAME) PERIODIC PROCESSES IN A UNIT OF TIME. FREQUENCY MEASURED IN CYCLES PER SECOND OR HERTZ (HZ) OR MEGAHERTZ (MHZ) WAVELENGTH - Answer THE DISTANCE BETWEEN TWO CONSECUTIVE PEAKS AND IS MEASURED IN MM, CM AND M WAVE - Answer THE PROPAGATION OF A WAVELENGTH OF ENERGY THAT HAS THE DIMENSION OF PERIOD, FREQUENCY AND AMPLITUDE AMPLITUDE - Answer THE SIGNAL (SINE WAVE) HEIGHT). THE GREATER THE AMPLITUDE, THE LARGER THE NUMBER OF PROTONS AND BRIGHTER THE IMAGE. ELECTROMAGNETIC (EM) WAVE - Answer SIMULTANEOUS PERIODIC VARIATIONS OF ELECTRIC AND MAGNETIC PROPERTIES AT 90 DEGREES TO EACH OTHER. SPIN - Answer PROPERTY OF CERTAIN SUBSTANCES WITH AN ODD NUMBERS OF NUCLEI (PROTONS AND NEUTRONS) THAT RESULT IN AN INTRINSIC ANGULAR MOMENTUM AND MAGNETIC MOMENT. EACH SPIN EXISTS IN A DISTINCT ENERGY STATE AND HAS AN IDENTIFIABLE SPIN QUANTUM NUMBER. DUE TO ITS SPIN THE H NUCLEIS PROTON HAS THE SAME PROPERTIES AS A BAR (DIPOLE) MAGNET. THIS SPINNING MOTION GIVES THE H PROTON A MAGNETIC MOMENT. MAGNETIC MOMENT - Answer THE MEASURE OF TH MAGNETIC PROPERTIES OF AN OBJECT OR PROTON THAT CAUSES THEM TO ALIGN WITH THE STATIC (MAIN) MAGNETIC FIELD, IT IS THE MAGNETIC FIELD OF A PROTON WITHOUT ANY RF PULSE APPLIED ANGULAR MOMENTUM - Answer THE ANGLE FORMED BETWEEN A PRECESSING OBJECT (PROTON) AND ITS IMAGINARY AXIS. THE VECTOR QUANTITY GIVEN BY THE PRODUCT OF THE MOMENTUM OF A PROTON AND ITS POSITION. IN THE ABSENCE OF EXTERNAL FORCES, THE ANGULAR MOMENTUM REMAINS CONSTANT, WITH THE RESULT THAT ANY ROTATING BODY TENDS TO MAINTAIN THE SAME AXIS OF ROTATION. WHEN A MAGNETIC FIELD IS APPLIED TO A ROTATING BODY THE RESULTING CHANGE RESULTS IN PRECESSION. PRECESSION - Answer THE PHENOMENON OF A MAGNETIC FIELD SPINNING R GYRATING AROUND THE AXIS OF ITS OWN CREATION ANTENNA - Answer A DEVICE ENABLING THE SENDING AND / OR RECEIVING OF ELECTROMAGNETIC WAVES RADIOFREQUENCY (RF) - Answer ELECTROMAGNETIC RADIATION LOWER IN ENERGY THAN INFRARED. THE RF USED IN MRI IS IN THE FORM OF A BURST OF RF ENERGY (PULSE) I THE 10 MHZ TO 100MHZ RANGE RF PULS, DELIVERED TO THE PATIENT BY RF TRANSMITTER. THE RF FREQUENCY, AT THE LARMOR FREQUENCY, RESULTS IN ROTATION OF THE NET MAGNETIZATION VECTRO AND PHASE COHERENCE OF THE NUCLEAR SPINS. AN RF COIL IS USED FOR TRANSMITTING AND RECEIVING MRI SIGNALS (RF). THREE BASIC COMPONENTS OF MAGNETIC RESONANCE - Answer 1. HYDROGEN PROTON 2. LARGE STATIC HOMOGENEOUS MAIN MAGNETIC FIELD. 3. RADIO FREQUENCY SIGNAL HYDROGEN - Answer SYMBOLIZED AS H OR H1. ALSO KNOWN AS THE PROTON, SPIN OR NUCLEI. AS THE INFORMATION UINIT (IU) FOR MAGNETIC RESONANCE, HYDROGEN'S PROTON, SUB-ATOMIC NUCLEI IS USEFUL BECAUSE: 1. ABUNDANCE; IT IS THE MOST ABUNDANT SUBSTANCE IN THE HUMAN BODY. 2. MAGNETIC MOMENT; IS HAS THE STRONGEST MAGNETIC MOMENT OF ANY SUBSTANCE. MAIN MAGNETIC FIELD/THREE CRITERIA FOR Bo - Answer SYMBOLIZED AS Bo AND MEASURED IN TESLA, IT IS THE ENVIRONMENT FOR MAGNETIC RESONANCE. 1. STABLE; MUST HAVE A FIELD STRENGTH THAT IS STATIC AND DOES NOT FLUCTUATE. 2. HOMOGENEOUS; THE FIELD MUST BE UNIFORM FROM THE ISOCENTER (SCAN AREA) TO FRINGE FIELDS (OUTSIDE THE SCAN AREA), IN ALL DIRECTIONS. 3. LARGE; Bo MUST BE LARGE ENOUGH TO ESTABLISH A SAMPLE OF PROTONS FOR DIAGNOSIS. RADIOFREQUENCY/ CRITERIA FOR RF SIGNAL - Answer SYMBOLIZED BY A SINE WAVE AND KNOWN AS B1, THE RF OR RF PULSE IS THE SIGNAL WHICH IS TRANSMITTED TO AND RECEIVED FROM THE PROTONS. 1. LARMOR FREQUENCY; ALSO KNOWN AS RESONANCE FREQUENCY OR PRECESSIONAL FREQUENCY. THE RF PULSE MUST BE INTRODUCED AT THE SAME FREQUENCY AS THE HYDROGEN PROTONS ARE PRECESSING. 2. THE RF PULSE MUST BE INTRODUCED PERPENDICULAR TO THE MAGNETIC FIELD OF BO