What is Imaging and Radiation?

#radioactive#overplayedWhat is Imaging and Radiation?The BASICSAnatomic imagine began at the turn of the century with Roentgen's discover of x-rays in 1896Advancements have allowed physicians (scientists) to look inside the body without the trauma and risk of explanatory surgery.

Modern TechniquesTraditional x-raysComputer Tomography (CT)Magnetic Resonance Imaging (MRI)Dynamic Spatial Reconstruction (DSR)Digital Subtraction Angiography (DSA)Positron Emission Tomography (PET)optical Coherent Tomography (OCT)Echo-planar MIR/UltrasoundRadiation BasicsRadiation is energy that comes from a source and travels through any kind of material and through spaceIonizing Radiation produces charged particles (Ions)Ionizing radiation is produce by unstable atoms; unstable atoms are said to be RadioactiveTo reach stability, these atoms give off energy; called Radiation

Types of RadiationOne typically encounters one of Three types: Alpha, Beta and Gamma RadiationNeutron radiation is also encountered in nuclear plants, high altitude flights and emitted from industrial radioactive sources

Alpha RadiationHeavy, very short range particle and actually an ejected helium nucleaseCharacteristic;Radiation Not able to penetrate human skin or clothingEmitted materials can be harmful to humansVery short distance; few inchesBeta RadiationLight, short range particle, and ejected electronCharacteristics:May travel several feet in air and moderately penetratingCan penetrate human skin to germinal layerMay be harmful if deposited internallyClothing provides some protection Gamma RadiationOr X-Rays, very long range, penetrating electromagnetic radiationCharacteristics:Able to travel many feet in air and many inches in human tissueSealed radioactive sources that emit gamma radiation and an external hazard to humansVisible light, radio waves and ultraviolet lightElectromagnetic radiations differ only in about of energy they haveGamma/X-rays have most energetic Clothing provides little shieldingRadiography or X-RaysRadiographyRadiography, known by most as X-Ray, uses electromagnetic radiation to make images of your bones, teeth, and internal organsX-rays allow DRs to take pictures inside the bodyThey Type of X-Ray depends on what part of the body needs examining and the purpose of the scanDifferent tissues absorb different amounts of radiationbones=dense, absorb X-Rays well; Appear WhiteSoft tissues; skin, fat, muscles and organs allow rays to pass, appear in varying shades of grayAir appears black; lungs Uses are as followsDetermine whether a bone is chipped, dislocated or broken (Fractured)Evaluate Joint injuries and bone infectionsDiagnose/monitor degenerative conditions; arthritisScreen for lung and heart diseaseFind and treat artery blockageDiagnose cause of persistent couching or chest painCheck from broken ribs/punctured lungEvaluate unexplained abdominal painHelp locate objects; maybe swallowed by a childDetect scoliosisEvaluate infection of the sinusesLocate dental problemsDetection of CancerPreparationsIn general:Undress area of body needing examination; may wear gownRemove jewelry, glasses, metal objects; Why?May need to wear a lead apron; to shield sex organs, Why?Medium Contrast; Barium and Iodine

ResultsImage films usually developed or viewed on-screen within minutesRadiologist typically views and interprets the resultsSends findings to doctor and than explain results

RISKS:What are some risks?Amount of radiation exposed to is extremely lowcancer?

Looking AheadX-Ray Technology has highly advanced from 1895X-ray Technology has specialized its imaging; such as mammography and Computerized Tomography Scanning (CT)Fluoroscopy; real-time imaging of body on videoX-Ray Therapy: kill cancer cells and shrink tumors

Thoughts?

Typically the views of the body by these technologies are:TransverseSagittal orFrontal sectionsSagittal and Frontal are less difficult to understand; however most CT & MRI images are transverseWhich is why understanding cross-section anatomy is highly important

Computerized Tomography (CT)Patient placed into a scanner and is exposed to a narrowly focused x-ray beamRadiation not absorbed is called Remnant RadiationData is collected by a computer and converted into Pixels (these make a digital picture)Image Reconstruction is when the computer combines the pixels to form an image (cross-Section)Takes over 262.000 pixels to form a single CT Image

A Contrast Medium is a dense liquid that prevents the passage of remnant radiation and appears white in a CT imageThis process is used to help with hollow organs (Blood vessels) to see contrastNew CT technology is able to produce an image so fast that physiological motions, respiratory or cardiac movements, do not blur the imageWhere are the most commonly used?ChestAbdomenPelvisSoft tissues of the neckbrain

Magnetic Resonance Imaging (MRI)Patient is placed into a scanner that produces a very powerful magnetic fieldAffects the nuclei of the atoms in patient's body to alignOnce aligned a Radiofrequency Pulse is used to establish a second field Data is collected by a computer by sensors to form pixels image reconstructionCan produces transverse, sagittal or frontal sectionsWhen pulse ends the hydrogen protons release an energy signal to realign with first magnetic fieldTime required is called Relaxation TimeTwo relaxation times: T1 (1st second image) and T2 (any time)

Appearance of Different Tissues in CT & MRI ImagesTissueCT ImageT1 MRI ImageT2 MRI ImageBoneWhiteBlackBlackMuscleGrayGrayDark GrayBrain White Matter Gray MatterDark GrayGrayGrayDark GrayDark GrayGrayFatDark Gray to BlackWhiteGrayCerebrospinal FluidBlackBlackWhiteBlood Flowing Non-FlowingWhite*White*BlackGrayBlackWhiteContrast MediaWhiteWhiteNot UsedAir-Filled Structures (lungs, stomach, etc.)BlackBlackblack*Only if iodinated contrast media is present; otherwise appears gray