Introduction of Radiographic Technology I Radiographic Terminology II

Introduction of Radiographic Technology I. Radiographic Terminology II. Basic Imaging Principles III. Positioning Principles

I. Radiographic Terminology n General Terms 1. 2. 3. 4. 5. 6. Radiography Radiograph vs. x-ray film Radiographic images Radiographic examination or procedure Anatomic position

I. Radiographic Terminology n Body Plane、Section and Lines Sagittal plane n Coronal plane n Horizontal plane n Oblique plane n Base plane n Occlusal plane n

I. Radiographic Terminology n Body Surfaces and Parts n For the body n anterior n posterior n For the hands and feet n plantar n palmar n dorsum

I. Radiographic Terminology n General Body Positions Supine n Prone n Erect (stand or sit) n Recumbent n Lying down in any position n Dorsal (supine) n Ventral (prone) n Lateral

I. Radiographic Terminology n General Body Positions Trendelenburg n Sim’s position n Fowler’s position n Lithotomy position n

I. Radiographic Terminology n Specific Body Positions The body part closest to the IR (oblique and lateral) or by the surface on which the patient is lying n Lateral n Right/Left n Oblique n LPO/RPO n LAO/RAO

I. Radiographic Terminology n Decubitus (Lie on a horizontal surface and always used with horizontal x-ray beam)

I. Radiographic Terminology n Radiographic Projection The direction or path of the CR of the x-ray beam n Anteroposterior n Posteroanterior n AP or PA Oblique n Mediolateral or Lateromedial

I. Radiographic Terminology n Additional Special Use Projection Terms n Axial n Superoinferior axial n Inferosuperior axial n AP/PA axial

I. Radiographic Terminology n Tangential AP axial (Lordotic) n Transthoracic lateral n

I. Radiographic Terminology Dorsoplantar / Plantodorsal n Parietoacnthial / Acanthioparietal n Submentovertex /Verticosubmental n

I. Radiographic Terminology n Relationship Terms Meidal vs. Lateral n Proximal vs. Distal n Cephalad vs. Caudad n

I. Radiographic Terminology n Terms Related to Movements Flexion/Extension/Hyperextension n Ulnar deviation/Radial deviation n Dorsiflexion/Plantar flexion of foot n

I. Radiographic Terminology n Terms Related to Movements Eversion (Valgus)/Inversion(Varus) n Medial /Lateral Rotation n

I. Radiographic Terminology n Terms Related to Movements Abduction/Adduction n Supination/Pronation n Protraction/Retration n

I. Radiographic Terminology n Terms Related to Movements Elevation/Depression n Circumduction n Tilt/Rotation n

I. Radiographic Terminology n Summary of Potentially Misused Terms n Position restricted to the discussion of the patient’s physical position n Projection restricted to the discussion of the path of the central ray n View restricted to the discussion of the a radiograph or image

II. Basic Imaging Principles 3 n Radiographic Criteria 2 1 6 Structures Show(1~6) n Position n Collimator and CR n Exposure Criteria n Image Markers n a c 4 5 b

II. Basic Imaging Principles n Image Markers and Patient Identification Patient ID and Date n Anatomic side marker n Additional markers or Identification n

II. Basic Imaging Principles n Radiographic Technique and Image Quality n Exposure factors n k. Vp n m. A n. S n (excepted when AEC is used ) Image Quality Factors n Density n Contrast n Detail n Distortion

II. Basic Imaging Principles n Density n n Definition：the amount of blackening of the processed image Controlling factor：m. As / k. Vp / SID Change rule ：Underexposure Doubling m. As Exception：DR and CR (controlled by image process technique)

II. Basic Imaging Principles n Contrast n n n Definition：the difference in density on adjacent areas of a radiographic image Purpose ：make the anatomic detail of a radiographic image more visible Controlling factor：k. Vp (15% increase as m. As double)

II. Basic Imaging Principles n Detail n n Definition：the visible sharpness of structure on the image Controlling factor n Geometric factors : focal spot size/SID/OID n Film/Screen Speed n Motion

II. Basic Imaging Principles n Distortion n Definition：the misrepresentation of object size or shape as projected onto film (because of beam divergence and SID)

II. Basic Imaging Principles n Distortion n Controlling factor n SID n OID/Focal spot size

II. Basic Imaging Principles n Alignment (object、film、CR)

II. Basic Imaging Principles n Anode Heel Effect Intensity of cathode > anode n Pronounced at Shorter SID n Larger IR n Small focal spot n

III. Positioning Principles n Professional Ethics and Patient Care n CAMRT (1997. 06) Canadian Association of Medical Radiation Technologists n ASRT (1994. 07) American Society of Radiological Technologists n n Protocol and Order for General Diagnostic Radiographic Procedures Room and Exam Preparation

III. Positioning Principles n Positioning Method Fixed vs. Floating tabletop n Cassette tray and Bucky grid n Beam restricting device n n Illuminated adjustable collimator n Positive Beam Limitation (PBL)

III. Positioning Principles n Positioning Sequences n Traditional Radiography Step 1 Step 2 Step 3 Step 4

n Table With bucky n no bucky n n Standing bucky

III. Positioning Principles n Essential Projections n Routine (Basic) Projections n Commonly taken on all patients who can cooperate fully n Special (Alternate) Projections n Better demonstrate specific anatomic or certain pathology n The patients who can’t cooperate fully

III. Positioning Principles n Principle for Determining Positioning Routine n A minimum of two projections n Problem of anatomic structures being superimposed n Localization of lesions or foreign bodies n Determination of alignment of fracture n A minimum of three projections n Skeletal system involving joints n AP、PA、Oblique

III. Positioning Principles n Topographic Positioning Landmarks Done gently n Patient should be informed n n Body Habitus

III. Positioning Principles n Viewing Medical Images n Radiographic Images n AP/PA/Oblique n n Viewing as patient is facing the viewer Marked by R/L

III. Positioning Principles n Lateral n n Viewing from the same perspective as the x-ray tube Marked R/L by the side of the patient closet to the IR n Decubitus n n chests and abdomen Viewing from the same perspective as the x-ray tube Crosswise and p’t upside on view box upside n Upper/lower n n n limb R/L marker appears right-side-up Limbs hanging down Digits up

III. Positioning Principles n CT or MRI Images n The patient’s right is to the viewer’s left

IV. Digital Imaging n PACS (Picture Archiving and Communication System)

IV. Digital Imaging n CR (Computed Radiography) n Key components n n Exposure factor( AEC is not used) n n Image plate (repeatedly) IP reader (laser scanner , 20 s) Workstation Compensation 500% overexposure， 80% underexposure Positioning consideration n n Center sampling technique Accurate and close collimation Lead masking for multiple images Grid

IV. Digital Imaging n DR (Digital Radiography ) n Flat panel receptor (direct conversion method ) Digital Bucky grid 17”*17” n Automatic Exposure Control (AEC) n n n k. Vp”、”m A” manual “s” auto

IV. Digital Imaging n DR in CGMH n Digital image unit

Quality Control for Processor l Set up initial standard (base line) l l l In most stable condition of the processor Individual O. D. of 21 steps (average of five days measurements) • Find O. D. ≧ 1. 2 Mid-density (MD) and Mid-step# • Find O. D. ≧ 2. 2 High-density (HD) and High-step# • Find O. D. ≧ 0. 45 Low-density (LD) and Low-step# Daily QA • MD < ± 0. 15 (measurement - base line) • DD < ± 0. 15 (measurement - base line) (DD=HD-LD)