TECHNIQUE

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TECHNIQUE

• EVERYTHING YOU WANTED TO KNOW BUT WERE AFRAID TO
  ASK!!!!

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Chapter 4 Fauber-Review Density CONTROLLING
FACTORS/INFLUENCING FACTORS pg 63

• m
• A
• s

• kVp
• Body Habitus
• SID/OID
• Screen
• Grids
• Collimation
• Thickness of the part
• Anode heel
• Reciprocity Law
• Tube filtration
• Compensating filters
• Film Processing
• Digital Processing

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Chapter 4 Fauber-Review CONTRAST controlling/infl
uencing factors pg 63

• k
• V
• p

• Grids
• Collimation
• OID
• Anatomic part
• Tube filtration
• Contrast medium
• Digital imaging

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Contrast and digital imaging

• kVp still important but.
• Contrast can be manipulated post processing
• Minimizing scatter important since DR is
  sensitive to scatter

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• TECHNIQUE REVIEW SID,OID,COLLIMATION,ANATOMIC
  PART, ANODE HEEL, GENERATOR OUTPUT,TUBE
  FILTRATION , COMPENSATING FILTERS
• FILM PROCESSING

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RECIPROCITY LAW

• DENSITY ON THE FILM SHOULD BE THE SAME FOR ANY
  COMBINATION OF mAs as long as the product of the
  mAs is equal!!!
• WHAAAAAT????
• 30 mAs
• 300mA x .1 30 mAs
• 200 mA x .15 30 mAs
• 500mA X .06 30 mAs

Same product
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It makes a difference

• DIGITAL
• EXPOSURE ERRORS OF 50 CAN BE ADJUSTED DIGITALLY
• THINK ABOUT THAT!

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LETS MOVE ON TO BUSHONG NOW

• CHAPTER 15
• PG 244

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LETS REVIEW

• TABLE 15-1 REMEMBER THIS?
• WHAT IS A FALLING LOAD GENERATOR?
• DIRECT SQUARE LAW?
• DOES FOCAL SPOT IMPACT TECHNIQUE?
• LETS MOVE ON TO PATIENT FACTORS, PG 251

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Exposure Technique charts

• What should be on a technique chart?
• Can the same chart be used for all tubes?

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Types of charts pg 260-265

• Variable kVp, Fixed mAs-
• short contrast/more pt exposure
• Fixed kVp, Variable mAs
• Prefered, longer contrast less patient exposure
• High kVp chart
• For exams using 100 kVp or higher
• Automatic exposure-PATIENT POSITIONING --VERY
  IMPORTANT
• kVp important
• OD important
• Collimation important
• Accessary selection
• Anatomically programmed radiography (APR)

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What do we do in these cases?

• Casts/splints
• Body habitus
• Pathology
• Is it always necessary to compensate?
• NOTE BOX 15-1 ON PAGE 253
• Soft tissue

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Understanding chest x-ray technical factors

• Inherently, the composition of the chest is high
  subject contrast.
• Black lungs. White bones

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Understanding chest x-ray technical factors

• Therefore to offset the short scale contrast, low
  mAs is used and high kVp is needed to add the
  long scale needed to see all anatomy

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CHART DEVELOPMENT-pge 263 in FAUBER

• Comparative anatomy
• Proportional anatomy

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Abd. 76 kVp, 20 mAsWhat do we adjust for the
following?

• Rose Aehle
• A thin but healthy person
• A Football linebacker or Santa Claus
• A frail, tiny,elderly person

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IT MAKES A DIFFERENCE

• mAs change of 30 or higher before a change is
  noted
• Changes in kVp in increments of 4 will produce a
  change in overall density and contrast especially
  in the lower kVp ranges.

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TRUE SCENARIO

• 80 YR OLD WHEELCHAIR BOUND MALE
• CANNOT GET OUT OF WHEELCHAIR
• SHOULDER IN NEUTRAL POSITION BUT A FRACTURE IS
  SUSPECTED
• TUBE DOES NOT EXPOSE AT 40SID
• CAN EXPOSE AT 72 SID BUT WALL BUCKY DOES NOT
  MOVE DOWN LOW ENOUGH TO PUT BEHIND THE PATIENT.
• WHAT POSITION AND TECHNIQUE SHOULD YOU USE?
  REFER TO TECHNIQUE CHART FOR THE ROOM THAT WAS A
  HANDOUT.