Portable Mobile Equipment and Applications RTEC 124 WEEK

Portable Mobile Equipment and Applications RTEC 124 – WEEK 12 SPRING 2011 1

Portable Objectives 1) Recommend methods for accomplishing acceptable variations of standard radiographic projections 2) Assess the radiation protection rules for mobile radiography 2

Objectives Continued 3) Identify factors contributing to the difficulty of mobile radiography 4) Explain appropriate communications methods for mobile examinations 5) Describe items that must be considered when arranging a patient room for a mobile examination 3

First “Portable “ Unit 4

Portable - DDR 5

THREE Basic types of Units Portable - refers to a small hand held unit, first designed by Picker for WW I • 15 ma generator • Chest & extremities Mobile - Full powered institutional units much heavier - motor or muscle driven Fluoroscopic: • C-arm and “Mini C-arm” or Fluoroscan • PORTABLE is accepted terminology 6

MOBILE XRAY UNIT 7

Basic Types of Mobile Radiography • • Battery Powered Unit Capacitor-discharge Unit High Frequency Units Mobile Fluoroscopic ( C-ARM) 8

Portable Units - Special Features • Battery Powered uses Ni-Cd rechargeable batteries, DC high frequency pulsed power • Capacitor-Discharged - uses 110 outlet. High voltage transformer - Capacitor discharges at time of exposure -voltage drops 1 kv/mas during exposure • High Frequency- converts hf AC to DC - resulting in high voltage ripple 60 hz-500 hz (square vs sine wave) • *Techniques are equivalent to 3Ø 12 p (like in a standard Radiographic room) 9

BATTERY POWERED 10

12 VOLT BATTERIES CAR BATTERY Silver or Nickel Cadmium 11

Power Drive • • • Self-propulsion for mobile unit Dead-man switch Must use caution when piloting equipment Weight of Equipment Areas: – safe and not safe to use 12

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“PLUG –IN” : Capacitor DISCHARE UNIT 14

Plug in – Light weight Cap. Discharge 15

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Types of Equipment • Power supplies • Generators • Power drive • Power Supplies: • Portable light duty units – 220 V or 110 V outlet • Full power mobile institutional units – Capacitor discharge – Battery operated 17

Generators • Capacitor discharge – Constant potential output • Battery operated – 3 phase output • THEREFORE – Technique is consistant with x-ray room • Grid is different 18

Milliampere-Seconds • Low power units not capable of high m. As techniques needed for grid radiography (300 m. A) • Double or triple exposure – Be careful not to overload tube – EX: X-table L 5 S 1 SPOT (in surgery) 19

AEC and Portables §This paddle with one or two cells § Placed behind the patient and cassette §Position of cells critical §Control Panel §Selection of density §back up time §cells 20

NEW – Mobile DIGITAL UNITS 21

DIGITAL UNITS 22

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COMPARISONS • Battery Powered • Uses 9 - 10 12 V batteries (heavy) • Battery supplies power for all inst. operations • Motor Driven • Wt - +1, 000 lbs • ? Constant potential • Some have AEC • Needs recharging - holds 8 hr charge • 3Ø 12 pulse techniques • Can double expose + • 110 V Capacitor DC • Uses 110 outlet • Capacitors stores up charge then exposure discharges • “Muscle Driven” • Wt - + 450 lbs • ? Constant potential • Some have programmed memory • Must be plugged in to store up charge • ? Not for large parts 25

HIGH FREQUENCY UNITS • Very Expensive – – not many in use • Smaller – more compact units • High voltage transformer 1/10 the size • Minimal voltage ripple – higher efficiency 26

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Min. Xray High Frequency Portable Units • Designed for use in: nursing homes, private homes, correctional facilities, field clinics, or hospitals, Maximum of 80 m. As 70 lbs 28

29 SUMMARY • Battery Powered Uses batteries 3Ǿ 12 p (4%ripple) • Capacitor Discharge Needs wall outlet Constant Potential (1 % ripple) • C-Arm Fluoroscopic Digital, Subtraction, Last Image Hold

“PREP” GETTING READY FOR EXAMS YOUR PATIENT THE ROOM YOURSELF 30

Special Patient Considerations • Communication • Manipulating equipment • Positioning and pathology 31

THE TECHNOLOGIST • The “ultimate test” of skill, competency and resourcefulness • Urgency and Tension • Patient’s inability to cooperate • Technical Considerations – – varying SID, – grid alignment – patient positioning 32

THE PATIENT • More acutely ill and/or unable to transport • More lines and tubes – Cardiac Monitoring – Ventilators – traction – Respirators • Levels of consciousness • Can they hear you or understand you? 33

Patient Considerations • Pre- portable rapport • Rearrange equipment/furniture • Leave it the way it was before you got there Locks on bars – bed rails – Table trays – Chairs – Pillows – Blankets – TV – etc 34

Other considerations • Overhanging TV’s and the X-ray tube can be hazardous to your head! • Don’t bump the bed or your head • Place cassette in a pillowcase when possible 35

GRIDS: lower ratio / more latitude Consider direction of grid lines to tube 36

Grid Ratio • Higher grid ratio – More efficient in removing scatter • Typical grid ratio range is 5: 1 to 16: 1 Watch positioning of CR to grid 37

38 Cassettes with Grid Caps

Grid Frequency • The number of lead strips per inch or cm • Frequency range – 60 -200 lines/in – 25 -80 lines/cm • Typically higher frequency grids have thinner lead strips 39

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KUB With and Without GRID 41

CR GRIDS Lower grid ratio = CR is more sensitive to scatter 42

Special Technical Factor Selection Considerations • • • Kilovoltage Milliampere-seconds Distance Grids Film/screen combinations Other factors 43

Distance • Measurements • For technique – – 40” 56” 63” 72” 44

ALARA • • Patient You Staff Friends and family 45

Legal Radiation Protection • It’s your duty • Politely ask whoever can, to leave the area – Provide aprons to those who cannot leave – Always carry 2 • Announce your intent to make an exposure 46

Ethical Radiation Protection • Never be in primary beam • Achieve maximum distance from the patient and tube – stand 90° from the patient • Minimum 6 foot exposure cord for radiography • Label and handle cassettes carefully 47

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MOVE ARTIFACTS WHEN POSSIBLE 49

Artifact under pt abd Move artifacts when possible 50

Types of Exams • Chest – AP, Lateral and LLD • Abdomen – AP or LLD • Cross table Hip • Extremities – 2 VIEWS - 90° • Cross table C-spine • Cross table T-spine • Shoulder (Y- view) 51

? ? QUESTIONS? ? 52