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Radiography Lecture Notes: Syllabus, PACO/POCO, Positioning, and Projections

Syllabus, PACO/POCO, Positioning, Planes, and Projections

  • Course logistics and tone

    • Read and understand the syllabus; ask questions for clarification as needed.
    • There is a syllabus quiz on Canvas due by Friday; may be required before diving into modules.
    • Syllabus discussion is brief; more details in lab on Wednesday.
    • Instructor intro: Missy (Ms. Benito is also acceptable); course is fast-paced and technical but aims to be engaging.

  • PACO overview (three-part workflow discussed throughout the course)

    • PACO stands for three parts of the initial procedure sequence:
    • P1: Prepare the patient
      • Explain the procedure, obtain patient history, verify that the exam requested matches the patient’s symptoms/areas of pain.
      • If anything is unclear, stop and reiterate as needed.
    • A: Adjust the control panel (imaging factors)
      • Mass (quantity of photons): referred to as milliampers/second in actual practice; controls how many photons are emitted.
      • mAs = milliampere × exposure time (seconds): \text{mAs} = \text{mA} \times t
      • kVp (kilovolt peak): beam quality/penetration; influences how photons penetrate tissue. Expressed as kVp.
      • Focal spot size: small focal spot for higher detail in extremities; large focal spot for larger areas (chest, abdomen).
    • O: Obtain the image receptor
      • In clinical sites, receptor may be called a cassette or a receptor; CR = computed radiography (uses cassettes); DR = digital radiography (image receptor stays on patient, digital only).
      • Most sites now use DR; some still use CR.
    • The POCO/POPO terminology for positioning-related steps will be revisited in lab; students are asked to reiterate on the POCO forms.

  • Positioning fundamentals and ARRT references

    • Positioning: setting the patient/part to best demonstrate anatomical structures.
    • Position is influenced by body habitus, patient ability, and exam adaptability.
    • A link to ARRT specifications for exams is provided in the slides for added context on registry expectations.
    • Blanks and memory aids are used to help memorize anatomical structures and positioning concepts.
    • Anatomical structures are the focus of positioning; the term is used alongside anatomical relations.

  • Anatomical planes and positions (foundational terms)

    • Planes of the body
    • Midsagittal plane: divides body into equal right and left halves.
    • Sagittal plane: divides body into left/right halves, not necessarily equal.
    • Mid-coronal (coronal plane): divides body into equal front and back halves.
    • Transverse (axial) plane: divides body into upper and lower halves.
    • A diagonal plane (not commonly referenced) mentioned for broader understanding.
    • Planes visualization references
    • A slide shows a coronal plane cutting front/back; a sagittal plane shows side-to-side division; a transverse plane is horizontal across the body.
    • Body positions and posture terminology
    • Supine: lying on the back (spine against the table).
    • Prone (noted as “crown” in the talk): lying on the abdomen/ventral side.
    • Erect (upright): standing.
    • Lateral: side-lying position (left lateral or right lateral).
    • Recumbent: any position lying down.
    • Oblique: at an angle—not strictly supine or prone.
    • Trendelenburg: recumbent with head lower than feet (used to improve circulation in low BP scenarios).
    • Bowler’s position: recumbent with feet lower than the head (opposite of Trendelenburg).
    • Anterior surface (ventral) vs posterior surface (dorsal);
    • Plantar (sole of the foot) vs palmar (palm) terms discussed for orientation.
    • Anatomical position reference notes
    • Anatomical position basics guide medial vs lateral and other directional terms.
    • The instructor emphasizes taking notes and uses hints to support memory.

  • Position vs alignment terminology in radiography

    • Position vs beam projection naming
    • Position refers to patient’s physical orientation against the table or imaging surface.
    • Projection refers to the path of the X-ray beam through the body; named by the direction of beam travel (e.g., AP, PA, lateral).
    • Example: Anterior-Posterior (AP) projection: beam enters from the anterior surface and exits posterior; Posterior-Anterior (PA) projection: beam enters from the posterior surface and exits anterior.
    • Oblique projections: named by the closest side to the receptor and the closest surface to the receptor (e.g., left posterior oblique, right anterior oblique).
    • Tangential and axial (angled) projections
    • Tangential projections skim between bones (e.g., patella-femur, zygomatic arch) to assess spacing and cartilage.
    • Axial projections involve an angle greater than 10 degrees on the tube; used for skull tangentials and other angled exams.
    • Decubitus projections
    • Decubitus requires a horizontal central ray and the patient in a recumbent position; used to evaluate air-fluid levels in chest/abdomen.

  • Radiographic alignment and the radiographic sandwich

    • Alignment is critical and involves three major components that must be properly aligned:
    • The X-ray tube (source)
    • The patient (object/part)
    • The image receptor (IR)
    • Analogy: a sandwich with three correctly aligned parts; misalignment leads to poor images.
    • Collimation
    • Controlled at the tube: the light field represents the radiation exposure area.
    • Goal: minimize dose and repeats by limiting the beam to the necessary anatomy plus a safety margin (informally called a penny slip).
    • Examples: wide collimation leaves more blank/soft tissue; tighter collimation improves detail and reduces dose.
    • Radiation protection and dose concerns
    • Collimation and shielding (especially gonads) are essential protection practices.
    • The patient dose, image quality, and potential repeats are balanced via technical factors.

  • Image receptors, detectors, and clinical realities

    • Image receptor types
    • CR (computed radiography): uses cassettes; after exposure, reads to display.
    • DR (digital radiography): direct digital image receptor on the patient; most sites now use DR, some still CR.
    • Marker usage and legal considerations
    • Every image should have a physical marker; digital annotations are not legally reliable in court.
    • Common required markers: left vs right markers; upright vs recumbent markers; time elapsed markers; anatomic level indicators; other special markers for non-standard exams.
    • The instructor will order markers to ensure compliance; personal markers are important.
    • In labs, expect to see different markers and procedures for placing them.
    • Image labeling conventions in practice
    • When taking images of joints or long bones, ensure proximal and distal joints are included as needed.
    • Two views are often necessary to prevent misinterpretation and to assess true anatomy (avoid misperceived pathologies from a single view).

  • Body habitus and clinical relevance

    • Body habitus concepts mentioned (some terminology used in the lecture differs from standard):
    • Splenic (average/sthenic): moderate build; thorax moderately short; balanced anatomy.
    • Spanic (likely a misstatement for sthenic): average body habitus.
    • Hypostenic: below average build; longer lungs; longer/thinner thorax; potentially shorter stature.
    • Asthenic: frail, very thin, long limbs, shallow thorax.
    • Hyperstenic (not explicitly named in the transcript but commonly contrasted): large, massive body habitus.
    • Why body habitus matters
    • Affects positioning options and the distribution of internal organs, which in turn influences chosen projections and technical factors.
    • Impacts how anatomy can be demonstrated and how exposure factors are selected.

  • Directional references and axes (for movement and positioning)

    • Directional terms related to the patient and projection orientation
    • Superior (cephalic): toward the head.
    • Inferior (caudal): toward the feet.
    • Anterior (ventral) vs posterior (dorsal).
    • Medial vs lateral relative to the body’s midline.
    • Axial skeleton movements and references
    • Left/right, anterior/posterior, superior/inferior, medial/lateral, and more medial-to-lateral movement within a region.
    • Appendicular skeleton movements and references
    • Similar terms (medial/lateral, anterior/posterior, proximal/distal) applied to limbs.
    • Specific actions: abduction (away from body) vs adduction (toward body).
    • Eversion (outward) vs inversion (inward).
    • Supination (palm face up) vs pronation (palm face down).
    • Rotation terms: lateral (external) vs medial (internal) rotation.
    • Joint actions: flexion vs extension.
    • Ipsilateral vs contralateral terminology
    • Ipsilateral: same side of the body as a point of reference.
    • Contralateral: opposite sides; common in stroke cases where brain involvement affects opposite body side.

  • Practical notes and exam preparation pointers

    • The instructor emphasizes asking questions and using the provided handouts (Canvas “Handouts” section) which include slide decks printed for students.
    • Fragmented lecture content is acknowledged as challenging, with promises of Lab demonstrations and room checkoffs in upcoming sessions.
    • Abbreviations common in radiology practice (examples mentioned):
    • SOB = shortness of breath
    • CHF = congestive heart failure
    • MI = myocardial infarct
    • RO = rule out
    • COPD = chronic obstructive pulmonary disease
    • PRN = as needed
    • FB = foreign body
    • The instructor stresses that abbreviations may be outdated and encourages spelling words fully in notes; practice with proper terminology is recommended.

  • Quick reminders for exam-style understanding

    • Two-view rule: many radiographs require two projections to avoid truncation/overlap and to verify spatial relationships (superimposition may hide pathology).
    • Projection naming relies on the path of the X-ray beam (e.g., PA vs AP); the patient’s orientation may be opposite of the projection naming.
    • Decubitus exams require a horizontal beam and recumbent patient setup to assess air-fluid levels.
    • Always consider the patient’s safety: minimize dose via collimation and shielding; ensure proper markers and labeling for legal purposes.
    • Lab and room checkoffs are upcoming; expect hands-on practice with room setups and marker placement.

  • Practical takeaways for now

    • Be comfortable with terminology for basic positions (supine, prone, upright/erect, lateral, oblique, decubitus).
    • Understand PACO/POCO workflow and what each step entails in a real exam.
    • Remember the three components of radiographic alignment and why collimation matters for dose and image quality.
    • Recognize the importance of markers and the legal implications of image labeling.
    • Prepare for quick recall of planes, directions, and projection relationships as you move into labs and clinicals.

  • End-of-session recap and next steps

    • Wednesday lab will revisit and expand on these concepts with hands-on practice.
    • Students will complete room checkoffs and apply PACO/POCO forms more thoroughly.
    • Quiz on course terminology is due by the end of the week; you have two attempts with at least an hour between attempts.