Portable Mobile Equipment and Applications

1. PortableMobile Equipment and Applications RTEC 124 – WEEK 12 SPRING 2011

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

3. 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

4. First “Portable “ Unit

5. Portable - DDR

6. 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

7. MOBILE XRAY UNIT

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

9. 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 1kv/mas during exposure • High Frequency- converts hf AC to DC - resulting in high voltage ripple 60hz-500 hz (square vs sine wave) • *Techniques are equivalent to 3Ø 12 p (like in a standard Radiographic room)

10. BATTERY POWERED

11. 12 VOLT BATTERIES CAR BATTERY Silver or Nickel Cadmium

12. 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

14. “PLUG –IN” : Capacitor DISCHARE UNIT

15. Plug in – Light weight Cap. Discharge

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

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

19. Milliampere-Seconds • Low power units not capable of high mAs techniques needed for grid radiography (300 mA) • Double or triple exposure • Be careful not to overload tube • EX: X-table L5 S1 SPOT (in surgery)

20. 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

21. NEW – Mobile DIGITAL UNITS

22. DIGITAL UNITS

25. COMPARISONS • Battery Powered • Uses 9 - 10 12V 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 12pulse 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

26. 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

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

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

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

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

32. 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

33. 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?

34. 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

35. 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

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

37. 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

38. Cassettes with Grid Caps

39. 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

41. KUB With and Without GRID

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

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

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

45. ALARA • Patient • You • Staff • Friends and family

46. 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

47. 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

49. MOVE ARTIFACTS WHEN POSSIBLE

50. Artifact under pt abd Move artifacts when possible