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.