Troubleshooting

 

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No Kr81m gas seen by the camera

Check for air flow with the bubble test

Poor Flow

  1. There may be a loose connection. Check all connections for a tight fit

  2. The wrong tubing may be used. One type of tubing has a rippled interior finish which leaks. Make sure the tubing is smooth bore.

  3. If a filter is used in the output line check that this is not blocked or wetted. A wet filter can obstruct the air flow

  4. The generator may be blocked (eg a displaced O-ring seal). Visually check any seals if possible. Take care not to tamper with the generator however!

  5. Check that the pump works with a separate bubble test without the generator in circuit.

Good Flow

  1. Check the camera is correctly peaked at 191kev for Kr81m

  2. Check the camera is working!

  3. If using an air cylinder, check that the humidifier is not blocked or leaks.

  4. Check that you have today's generator! (eg has an old generator been connected by mistake).

Slow Kr81m Images

  1. Check the camera is correctly peaked at 191kev for Kr81m

  2. Check that you have the correct collimator

  3. Check for any gas leaks (do a bubble test)

  4. Check that the generator activity is not low (eg poor production run)

  5. If using an air cylinder, check that the humidifier is in place and has no leaks.

  6. check that the patient has a good seal with the face mask.

 

Poor Image Quality

  1. Check the camera is correctly peaked at 191kev for Kr81m

  2. Check that you have the correct collimator

  3. Are the images slow and have too few counts? - check slow Kr81m images above. If using a dual energy acquisition protocol then the counts may be too low. Change the time for the Kr81m view or acquire using single views.

  4. Check the patient aspects. Is the facemask a good fit? If the patient is poorly and cannot breath in the Kr81m efficiently or have a good mouthseal then there may be Kr81m gas leaks into the field of view of the camera. Hold the facemask firmly to form a good seal. If this cannot be achieved then use a fan to blow any Kr81m gas leakage away from the camera face.

 

 

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Last modified: November 29, 2002