1a - Positioning Basics

Question 1

Radiographic Density

Answer 1

more dense tissue will appear LIGHTER on x-ray

• Thickness of bodypart affects density

Question 2

Radiographic positioning

Answer 2

the placement of the bodypart between the Xray tube and the film (image receptor = IR)

Question 3

How many views are needed when taking Xray?

Answer 3

Minimum of 2 opposing views

• Preferable at 90 degrees

Question 4

“Series” of xrays

Answer 4

the minimum amount of xrays needed to complete the exam

• For insurance purposes

Question 5

Projection

Answer 5

the path of the xray bean (CR) as it enters and exits the body

Question 6

View

Answer 6

the beam’s perspective

Question 7

Position

Answer 7

the placement of the body or part

• Upright(Standing or seated)
• Recumbent (Prone/supine)
• AP or PA
• Refer to bodypart against the IR
  
  • Oblique:RAO, RPO, LAO, LPO
  • Lateral:Left, Right

Question 8

Lateral

Answer 8

the coronal plane that is perpendicular to IR

• Refer to the side touching the IR

Question 9

Oblique

Answer 9

the body (or part) is rotated from normal Anatomic Position

Question 10

Axial view

Answer 10

There is more than 10 Degree tilt between the part and CR

• Usually the tube is tilted

Question 11

Tangential view

Answer 11

The CR intersects an object at only one point on the suface

• “Skimming a body part”

Question 12

Decubitus view

Answer 12

Pt is recumbent, CR is horizontal, IR is vertical

• Checks for air/fluid levels

Question 13

Air-fluid levels seen with which xray views?

Answer 13

demonstrated on upright and on decubitus views only

Question 14

Basic rules for positioning

Answer 14

1. CR is centered to the middle of the part (CR –> Center body part –> Center of film)
2. The long axis of the bodypart is parallel to the long axis of IR
3. CR is directed perpendicular to the part (and IR)

Question 15

Controlling magnification distortion

Answer 15

• Keep bodypart as close to IR as possible
• Compensate by increasing the Source-to-Imagine Distance (SID) if there is notable OID that cannot be reduced

Question 16

Shape distortion control

Answer 16

• No rotation or tilt of bodypart
• No tube tilt

Question 17

When can distortion be helpful?

Answer 17

When isolating a specific bodypart

Question 18

SID to minimize magnification distortion

Answer 18

• 40”
• Exceptions (need to use 72”)
  
  • Lateral Cervicals
  • Oblique Cervicals
  • Lateral Chest
  • PA Chest
  • AP full spine

Question 19

Topographic landmarks: Mastoid tip, Thyroid cartilage, Vertebral Prominens

Answer 19

• C1 = Mastoid tip
• C4 = Thyroid cartilage
• C7 = VP

Question 20

Topographic landmarks: Sternal notch, Sternal Angle, Xyphoid tip

Answer 20

• T2 = Sternal notch
• T4 = Sternal angle
• T10 = Xyphoid tip

Question 21

Topographic landmarks: Iliac crest, ASIS

Answer 21

• L4/5 = Iliac crest
• S2 = ASIS

Question 22

Topographic landmarks: Greater Trochanter, Ischial Tuberosity

Answer 22

• Coccyx tip = Greater trochanter
• Bottom of pelvis = Ischial tuberosity

Question 23

Collimation function

Answer 23

• Limits radiation
• Controls unwanted scatter

Question 24

ID blocker

Answer 24

allows no exposure to film

• Place it AWAY from anatomy of interest

Question 25

Effects of respiration

Answer 25

* Controls “voluntary” motion = reduce blurriness * Anatomy determines when to hold breath * Cervical = out * Thoracic = in * Lumbar = out

Question 26

What units do Calipers measure in?

Answer 26

Centimeters

Question 27

What material is in gonadal shielding?

Answer 27

Lead vinyl sheets

Question 28

Flat Aluminum filters

Answer 28

* Evens out radiographic density * Placement * Between xray beam and Pt * Over **thinnest** portion of intended anatomy * Protects from exposure

Question 29

Pregnancy and xray

Answer 29

* Delay xray if possible * Shield fetus if xray is necessary * 10 day rule = safest tiem to xray women of childbearing age is within 10 days after onset of menstruation

Question 30

Pt Prep

Answer 30

* Remove clothing and put on gown * Remove all artifacts * Shield appropriately * Explain procedure * Measure Pt with calipers * Control voluntary movment

Question 31

Equipment prep

Answer 31

* Set Source-to-Image Distance (SID) * 40” or 72” * Set tube tilt (typically perpendicular to anatomy) * Put cassette in bucky * Collimate to part size and orientation * Apply anatomical marker * Add filtration (if needed, over thinnest part)

Question 32

Summary of Set-up

Answer 32

1. prep Pt and set exposure 2. set SID, and tilt tube 3. select film size and align to part 4. positon Pt/part 5. align CR—part—IR 6. collimate to part 7. apply anatomical marker 8. apply filter (if needed) 9. give breathing instructions 10. make exposure and change IR

Question 33

Info needed for legal xray identifiers

Answer 33

* Patient’s * Number * Name * DOB * Exam info * Facility info * Correct anatomical marker