Lecture-1 Radiographic principles and fundamentals.pdf

RMI 221 Radiographic Anatomy & Positioning 1 Lecture 1 Radiographic Principles and Fundamentals Slide 1 fchs.ac.ae Learning Outcomes After today’s lecture you will be able to: List the key radiographic requirements for a radiographic...

RMI 221 Radiographic Anatomy & Positioning 1 Lecture 1 Radiographic Principles and Fundamentals Slide 1 fchs.ac.ae Learning Outcomes After today’s lecture you will be able to: List the key radiographic requirements for a radiographic examination. Identify the basic imaging principles of exposure factors. Begin to distinguish between image and diagnostic quality. Slide 2 fchs.ac.ae Reading The prescribed texts relating to this lecture are: Bontrager, K.L. & Lampignano, J.P. (2010), Textbook of Radiographic Positioning and Related Anatomy, 7th edition, Mosby, St. Louis, Missouri. McQuillen Martensen, K. (2011), Radiographic Image Analysis, 3rd edition, W.B. Saunders, St. Louis, Missouri. The prescribed reading is: Bontrager, K. & Lampignano, J. (2010), Textbook of Radiographic Positioning and Related Anatomy, 7th edition, Mosby, St. Louis, Missouri, Chapter 5, pp.124-125, 138, 147-151. Slide 3 fchs.ac.ae  Common Abbreviations Abbreviation Meaning MSP Medial Sagittal plane FFD Focal Film Distance PA Posteroanterior AP Anteroposterior Lat Lateral RAO Right Anterior Oblique LAO Left Anterior Oblique RPO Right Posterior Oblique fchs.ac.ae  Common Abbreviations LPO Left Posterior Oblique CR Central Ray ASIS Anterior Superior Iliac Spine D.O.B Date of Birth LMP Last menstrual Period MAS Millie Ampere Second KV Kilo Voltage fchs.ac.ae Overview 1. Radiographic examination – Requirements 2. Imaging principles: Exposure factors – kVp – mA and mAs 3. Quality Slide 6 fchs.ac.ae 1. Radiographic Examination Discussion question: What do we need to know to perform a radiographic examination? Slide 7 fchs.ac.ae Radiographic Examination: Requirements Comprehend and apply radiographic and medical terminology. Interpret the request form and plan the examination. Slide 8 fchs.ac.ae Radiographic Examination: Requirements - Request Form Image: Fig 1-118, McQuillen Martensen (2011), p.57. Slide 9 fchs.ac.ae Radiographic Examination: Requirements (continued) What else? Radiographic positioning principles Anatomy Standard or routine radiographic projections (protocols) independent of the clinical indications Slide 10 fchs.ac.ae Radiographic Examination: Requirements (continued) Anything else? Modifications – How to modify the standard or routine projections (evaluation of the patient) – Positioning methods: how to modify technique to account for body habitus and pathology – Supplementary or additional projections : based upon the clinical conditions Slide 11 fchs.ac.ae Radiographic Examination: Requirements (continued) Is that everything? Radiographic technique: exposure factors/ collimation Central Ray (C.R.) - location and direction Principles of radiation safety Radiographic anatomy and pathology Image: Fig 1-66, McQuillen Martensen (2011), p.32. Slide 12 fchs.ac.ae Radiographic Examination: Requirements - Evaluation Criteria An optimal radiograph should demonstrate:  maximum recorded detail  accurate patient positioning  adequate penetration  optimal density  optimal contrast  no motion artifact  no removable artifacts such Image: Fig 1-98, McQuillen Martensen (2011), p.49. as rings, watches Slide 13 fchs.ac.ae 2. Imaging Principles: Exposure Factors Factors that the radiographer manipulates and sets on the x-ray console Kilovoltage (kVp) kVp controls radiographic contrast Milliamperage (mA) Time in seconds/milliseconds (sec/ms) Slide 14 fchs.ac.ae Imaging Principles: Exposure Factors Kelly (2003) suggests the following kVp levels for: Fingers, hand and toes 50 Wrist, elbow, foot, ankle and knee 60 Acute abdomen and majority of skeleton 80 Abdominal work using IV contrast and lateral thoracic spine 70 Lateral lumbar spine and skull vault 90 Chest with grid 100 - 120 These are based on traditional analog film/screen combinations; however, they are still applicable in the digital world. Slide 15 fchs.ac.ae Imaging Principles: Exposure Factors - Ideal mA Fingers, hand and toes 100 Wrist, elbow, foot, ankle and knee 100 Abdomen, spine and shoulder 200 Chest with grid 300 - 400 Fig 2-1, Bontrager & Lampignano (2010), p.37. Slide 16 fchs.ac.ae 3. Quality: Image Quality vs Diagnostic Quality Are image quality and diagnostic quality the same? Image quality and diagnostic quality are not necessarily synonymous. A radiograph can be produced with less than optimal quality but it is nevertheless accepted as being diagnostic. This is an important clinical decision that the radiographer makes. Slide 17 fchs.ac.ae Image Quality vs Diagnostic Quality: Decision Making This image meets all the required This image is not as well positioned image quality evaluation criteria. but demonstrates the pathology so has diagnostic quality. Slide 18 fchs.ac.ae 2. Anatomical Terminology: Axial Skeleton Total adult skeleton - 206 separate bones Axial skeleton (80 bones) - Central axis of body - Skull, vertebral column, ribs, and sternum Fig 1-12, Bontrager & Lampignano (2010), p.6. Slide 11 fchs.ac.ae Anatomical Terminology: Appendicular Skeleton Appendicular skeleton (126 bones) - Limbs (Semester 1) - Shoulder and pelvic girdles (Semester 2) Fig 1-13, Bontrager & Lampignano (2010), p.7. Slide 20 fchs.ac.ae Anatomical Terminology (continued) Remember the anatomical position (from Lecture 1) (Bontrager & Lampignano, 2010, p.14) *This is the reference position for all other positions.* Fig 1-35, Bontrager & Lampignano (2010), p.14. Slide 21 fchs.ac.ae Anatomical Terminology (continued) Body positions: (Bontrager & Lampignano, 2010, pp.18-20) General - erect, supine, prone, trendelenburg, recumbent Specific - lateral, oblique, decubitus Fig 1-51, Bontrager & Lampignano (2010), p.18. Fig 1-60, Bontrager & Lampignano (2010), p.19. Slide 22 fchs.ac.ae Anatomical Terminology (continued) Planes: Sagittal - vertical plane dividing left/right Coronal- vertical plane dividing anterior/posterior Transverse/axial - horizontal plane dividing superior/inferior (at right angles to sagittal/coronal planes) Fig 1-35, Bontrager & Lampignano (2005), p.15. Slide 23 fchs.ac.ae Anatomical Terminology (continued) Body surfaces: Posterior (dorsal) Anterior (ventral) Surfaces for the hands/feet: Plantar - posterior or sole (foot) Fig 1-41, Bontrager & Lampignano (2005), p.16. Dorsum - anterior or top (foot) Palmar - palm of hand or anterior surface (anatomical position) Fig 1-42, Bontrager & Lampignano (2005), p.16. Slide 24 fchs.ac.ae Anatomical Terminology (continued) Movements: Flexion - angle decreased Extension - angle increased Fig 1-87, Bontrager & Lampignano (2005), p.25. Fig 1-90, Bontrager & Lampignano (2005), p.26. Slide 25 fchs.ac.ae Anatomical Terminology (continued) Movements (continued): Abduction - movement away (mid line) Adduction - movement toward (mid line) Fig 1-94, Bontrager & Lampignano (2005), p.27. Slide 26 fchs.ac.ae Anatomical Terminology (continued) Movements (continued): Supination - rotation with palm up Pronation - rotation with palm down Fig 1-95, Bontrager & Lampignano (2005), p.27. Slide 27 fchs.ac.ae 3. Radiographic Terminology (Revisited) Do you remember these terms and their differences? Radiograph (x-ray/image): The photographic image of an anatomical part of a patient Radiographic projection: Positioning term describing the path of the x-ray beam, its entrance and exit points Radiographic position: Body placement for the radiograph Slide 28 fchs.ac.ae  PROJECTION Refers to the path the beam takes through part Anteroposterior projection (AP) Beam enters the front surface and exits the back surface of the part AP projection in supine position fchs.ac.ae Posteroanterior projection (PA) Beam enters the back and exits the front of the part PA projection in prone position fchs.ac.ae  Erect "upright" Position when the Sagittal and coronal planes of the body are perpendicular to the horizon fchs.ac.ae  Recumbent "lying down" Position when the transverse plane of the body is perpendicular to the horizon. fchs.ac.ae  DECUBITUS Patient is lying down & the x- ray beam is parallel to the horizon fchs.ac.ae  Decubitus vs. recumbent General meanings are the same "LYING DOWN" But in radiography, decubitus has a special meaning fchs.ac.ae  Recumbent Positions Supine (posterior recumbent position) – Lying down on the back. Prone (anterior recumbent position) – Lying face down fchs.ac.ae Right lateral recumbent - lying down on the right side Oblique (Erect or Recumbent) Position when the body is rotated so that the medial sagittal plane (MSP) is neither nor to the film but at an angle Exact position is indicated by the surface closest to the film and the angle of rotation May be erect or recumbent Abbreviations: ( RPO, LPO, RAO, LAO) 45 degres RPO fchs.ac.ae  Decubitus Positions Ventral decubitus: Patient is prone & a horizontal beam is used Dorsal decubitus : Patient is supine & a horizontal beam is used fchs.ac.ae Left lateral decubitus : Patient lying on the left lateral side & a horizontal beam is used fchs.ac.ae  Erect Positions Surface of body closest to the film used to give a more specific description. Examples: Posterior erect – Patient is standing with the posterior surface of the body next to the cassette. fchs.ac.ae  Left lateral erect Patient is standing with the left side of the body next to the cassette Left lateral erect position fchs.ac.ae Radiographic Terminology: Radiographic Projections vs Radiographic Positions Projections: Commonly denoted as acronyms indicating the surfaces traversed by the path of the x-ray beam: AP (Anteroposterior) PA (Posteroanterior) Axial Tangential IS SI LPO RPO LAO RAO Fig 3-51, Bontrager & Lampignano (2005), p.90. Fig 6-35, McQuillen Martensen (2011), p.326. Slide 41 fchs.ac.ae Radiographic Projections vs Radiographic Positions (continued) Positions: Again denoted as acronyms that indicate the body surface closest to the IR: Lateral* Oblique** * + L or R = position ** + L or R and surface = position + AP or PA = projection Fig 3-54, McQuillen Martensen (2011), p.131. Slide 42 fchs.ac.ae Radiographic Projections vs Radiographic Positions (continued) Positions (continued): Erect Recumbent Decubitus (lying down + horizontal beam): lateral, supine, prone Fig 3-35, McQuillen Martensen (2011), p.113. Slide 43 fchs.ac.ae 4. General Radiographic and Imaging Principles: Radiographic Positioning A minimum of two projections at right angles (orthogonal) to: overcome superimposition of anatomical structures localize and locate lesions or a foreign body (FB) determine alignment of fractures confirm pathology www.office.microsoft.com/clipart Slide 44 fchs.ac.ae General Principles (continued) Exception to right angle principle: (Minimum of Three projections when joints are in the area of Fig 7-83, Bontrager & Lampignano (2010), p.237. interest): Three projections or positions are required when examining joints of the body, i.e., an oblique is required to demonstrate chip fractures or other abnormalities in joint spaces. Fig 1-107, Bontrager & Lampignano (2010), p.33. Slide 45 fchs.ac.ae Activity 2: How Many Minimal Projections Required? Hand 1, 2, or 3 projections Forearm 1, 2, or 3 projections Femur 1, 2, or 3 projections Knee 1, 2, or 3 projections Humerus 1, 2, or 3 projections Slide 46 fchs.ac.ae General Principles: Standardization of Radiographic Projections Why standardize? To gain maximum diagnostic information about the patient while creating the minimum radiation hazard. To make images diagnostically reliable. To enable radiographic examinations to be repeated and directly comparable to previous studies. Slide 47 fchs.ac.ae General Principles: Radiographic Procedural Technique Central Ray (CR) SID/FFD Patient position Exposure factors Collimation Radiation protection Fig 1-109, Bontrager & Lampignano (2005), p.34. Fig 2-17, Bontrager & Lampignano (2010), p.44. Slide 48 fchs.ac.ae General Principles: Radiographic Exposure Factors Exposure factors - a general look Kilovoltage (kVp), Milliamperage (mA) and Time (s): Kilovoltage or kVp represents the penetrative power of x-rays. Millamperage or mA represents the current flowing through the x-ray tube. mAs is the product of the time in Fig 2-1, Bontrager & Lampignano (2010), p.37. seconds or less and the mA. Slide 49 fchs.ac.ae General Principles: Collimation Collimation = act of restricting the x-ray beam to region of interest (ROI): To reduce the radiation hazard to the patient. To improve the radiographic contrast of the image by minimizing scatter radiation. * Four border collimation - the objective of every radiographer. Fig 4-88, McQuillen Martensen (2011,) p.244. Slide 50 fchs.ac.ae General Principles: Radiation Protection Radiation protection = to areas beyond the ROI. Figs 2-69 & 2-70, Bontrager & Lampignano (2010), p.65. Selection of radiographic exposure technique Positioning of the patient Provision of gonadal shielding Pregnancy check Slide 51 fchs.ac.ae General Principles: Image Quality - Traditional or Analogue Factors In traditional film/screen or analogue systems: Contrast = variation in density between adjacent areas on a radiograph (kVp) Density = the amount of “blackening” on a radiograph (mAs) Detail = visible sharpness of structures on a radiograph (geometrical factors) Distortion = misrepresentation of the actual object as projected onto a radiograph (angles) (Bontrager & Lampignano, 2010, pp.42-46) Slide 52 fchs.ac.ae General Principles: Image Quality Factors - Contrast Short scale = high contrast (low kVp) There are greater differences in adjacent densities and fewer visible density steps as illustrated in the step wedge. Fig 2-7, Bontrager & Lampignano (2010), p.40. Slide 53 fchs.ac.ae General Principles: Image Quality Factors – Contrast (continued) Long scale = low contrast (high kVp) There are fewer differences in adjacent densities as illustrated in the step wedge. Fig 2-8, Bontrager & Lampignano (2010), p.40. Slide 54 fchs.ac.ae  Compare Long scale Short scale Figs 2-7 & 2-8, Bontrager & Lampignano (2010), p.40. Slide 55 fchs.ac.ae General Principles: Image Quality Factors - Detail Loss of sharpness primarily due to motion: Voluntary Involuntary Fig 2-15, Bontrager & Lampignano (2010), p.43. Fig 2-8, Bontrager & Lampignano (2005), p.46. Slide 56 fchs.ac.ae Image Quality Factors: Distortion Controlling factors: SID (Source Image Distance) OID (Object Image Distance) Object film alignment C.R. alignment Figs 2-18 & 2-19, Bontrager & Lampignano (2010), p.45. Slide 57 fchs.ac.ae General Principles: Presentation of Radiographs *A radiograph is a legal document.* It is the radiographer’s responsibility to ensure that all appropriate information is clearly and accurately displayed: Patient and departmental data Positioning of the plate (orientation) Fig 1-101, Bontrager & Lampignano (2010), p.30. Slide 58 fchs.ac.ae General Principles: Presentation of Radiographs (continued) Accuracy, visualization and use of “side” markers: Is the left side of the body part really the left side? Is the body position clear? Additional information regarding patient position. Fig 1-103, Bontrager & Lampignano (2010), p.30. Slide 59 fchs.ac.ae