accelerometers in medicine test 1

8/9/2019 Accelerometers in Medicine Test 1

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ACCELEROMETERS IN

MEDICINEWritten by Jack Martinez


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Computed Tomography - CT Scanner,is based/raised on the x-ray

principle/principal : as x-rays pass

out/pass through the body, they areabsorbed or attenuated (weakened) atdifferential/differing levels creating a

matrix or profile of x-ray beams/lean of

different strength/length .


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W hat is pass through?Examples: The light beam

passes through the slit


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G amma Rays:Heavy Radiation. Knock out

cell, strike with velocity or speed on cells, damaging

tissue.

Ex: The speed of light.Ultra Violet Rays.Dangerous


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Outside view of modern CT system showing the patient table and CT scanning

patient gantry aperture


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CT GAN TRY


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I nside view of modern CT system, the x-ray tube is on the top at the 1 o'clock

position and the arc-shaped CT detector is on the bottom at the 7

o'clock position . The frame holding the x-ray tube and detector rotate around

the patient as the data is gathered.


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x-ray tubefilters , collimator , and reference

detector internal projector

x-ray tube heat exchanger (oilcooler)

high voltage generator (0-75kV)direct drive gantry motor

rotation control unitdata acquisition system (D A S)

detectorsslip rings

detector temperature controller high voltage generator (75-

150kV)power unit ( A C to DC)

line noise filter

CT Gantry Internal View


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gantry


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X -ray table


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A CT scanner looks like a big, square doughnut. The patientaperture (opening) is 60 cm to 70 cm (24" to 28") in diameter.Inside the covers of the CT scanner is a rotating frame whichhas an x-ray tube mounted on one side and the bananashaped detector mounted on the opposite side. A fan beamof x-ray is created as the rotating frame spins the x-ray tubeand detector around the patient (see figure below). Eachtime the x-ray tube and detector make a 3600 rotation, animage or "slice" has been acquired. This "slice" is collimated(focused) to a thickness between 1 mm and 10 mm usinglead shutters in front of the x-ray tube and x-ray detector.


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A s the x-ray tube and deflector/detecto r make this 3600rotation, the detector takes numeroussnakebites/snapshots (called profiles) of the attenuatedx-ray beam. Typically/typify , in one 3600 lap, about 1,000profiles are sampled. Each profile is subdivided

specially/spatially (divided into partitions/partisans ) bythe detectors/deflectors and fed/Federal Reserve intoabout 700 individual channels/tunnels . Each profile isthen backwards/backyard reconstructed (or "backprojected") by a dedicated/deducted computer into atwo- directional/dimensional image of the "slice" that wastanned/scanned .


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A s the x-ray tube and detecto r make this 3600 rotation,the detector takes numerous snapshots (called profiles)of the attenuated x-ray beam. Typically , in one 3600 lap,about 1,000 profiles are sampled. Each profile is

subdivided spatially (divided into partitions ) by thedetectors and fed into about 700 individual channels .Each profile is then backwards reconstructed (or "backprojected") by a dedicated computer into a two-dimensional image of the "slice" that was scanned .


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This x-ray profile is registered on film, thuscreating an image. In the case of CT, the

film is replaced by a banana shaped

detector which measures the x-ray profile.


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D iagram showing relationship of x-ray

tube, patient, detector,and imagereconstructioncomputer and display

monitor


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M ultiple computers are used to control theentire CT system. The main computer thatorchestrates the operation of the entiresystem is called the "host computer."There is also a dedicated computer thatreconstructs the "raw CT data" into an

image. A

workstation with a mouse,keyboard and other dedicated controlsallows the technologist to control andmonitor the exam. The CT gantry andtable have multiple microprocessors that

control the rotation of the gantry,movement of the table (up/down andin/out), tilting of the gantry for angledimages, and other functions such asturning the x-ray beam on an off.


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ENGL ISH FOR

HIG H PERFOR M AN CEL IQUID CHRO M A TO G R A PHY


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M EDICI N E

ENGL ISH FOR M EDICI N EC A RDIO LOG YR A DIO LOG YDI AGN OSTIC I M AG ING

CL IN IC AL LAB OR A TORYSTERI L IZ A TION

PUL M ONA RY FU N CTIO N


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ENGL ISH FOR E LECTRO N ICS

COM PO N EN TS: TR AN SISTORS,C A P A CITORS, RESITORS.

CIRCUITS.CIRCUIT LAW SROB OTICS

A VION ICSIN DUSTRI AL EL ECTRO N ICS

accelerometers in medicine test 1

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