DEXA GE Lunar PIXImus Bench Protocol  

Revision #: 5.0, Jan. 18, 2005, , RVS,WR

Machine Start-Up & Quality Control:

  1. Leave the PIXImus machine on all the time.
  2. Turn on the computer dedicated to the PIXImus machine, let warm up ~ 5 min.
  3. Click on the LUNAR Pixi icon twice to display the PIXI screen.
  4. Go under F6 and select quality control.
  5. You will be prompted to place the QC phantom in the path of the x-ray beam.
  6. Press F3 to start the measurement and then hit OK twice.
  7. After you have received a passing QC scan, print it off for the log book.
  8. Hit F8 to escape and return to the start screen.

Subject preparation:

  1. Once you have weighed the first mouse to be scanned and given it the proper amount of Avertin (0.02 ml of a 2% tribromoethanol solution per gram of body weight), log it into the log book. After logging the information, enter it into the Piximus program.  The Subject ID is the mouse's PED number. The description is the Histo number. Enter the weight of the mouse and the born date. You can also enter the nose to anus (n/a) length at this time.
  2. When you have entered all the information that you need, hit the OK button.
  3. When placing the mouse on the sticky tray, do not go over the blue line. Put the tail along the side of the body and pull the front legs back to the side of the mouse. Place your two index fingers along the back bone and straighten out the back. The neck should be stretched and straight.
  4. The mouse is now ready to be placed on the machine.

Performing the scan:

  1. Hit the Enter key and the F3 button to start the scan.
  2. After the scan is done, hit the F3 button twice to adjust the ROI (region of interest). This is where you will adjust the scan to measure what you want to have analyzed. The green circle is usually put over the head to remove it from the scan. It is the densest part of the body and will tend to throw off the bone density. When the circle is green, you can move it around by using your arrow keys. If you hold down the Shift and Control keys, you can adjust the size and position of the circle. Hold them separately or together to move the circle faster. If you need to move the box, hit the Tab key to change the box to green. Once it is green, you can adjust it the same way. If you are doing a head scan, this is the best way to do it. You can also change the position of the box to a certain angle by using the Page Up and Page Down keys.
  3. After you have the desired scan, hit the Enter key, hit F8 twice and then hit F6 to log your results.
  4. Hit F5 to print your results.
  5. After you have printed your scan, hit the F8 key twice to exit the scan.
  6. You will then be returned to the main screen.
  7. Hit F3 to start the next scan.
  8. Select previous subject to bring up the last scan which you can then edit to add the new mouse’s data, or you can re-enter everything.

Data collection:

(Data collected on the Piximus computer needs to be moved to the HLB-archive computer so that it can be processed into the database and be securely archived for future reference.  The current Piximus software does not allow the Piximus computer to be connected directly to the laboratory network.  For now the data is transferred manually using a USB disk drive).

To collect data, you will need a USB data transfer stick. You will plug in the data stick and you will have to double click on “Datapixi” folder and open it up. Then go to your folder named “moved data waiting”. Click on folder and open it up. You can transfer around 60 img’s to the data stick at a time. Highlight the files you want to copy (single click of the mouse, Ctrl click to add to list, Shift click to highlight a block).  Use copy (Ctrl c) then mover into the Pixi data folder on the data stick and Paste (Ctrl v) the data (you can also use the right click on the mouse to access Copy and Paste functions). To remove the data stick, click on the green arrow with the card (safety removal USB mass storage device).   Transfer the USB data stick to a computer on the laboratory network.  The USB drive will become the next available disk drive, on the current computer this will be removable disk “F”. Open up Pixi data again and begin transfer all files over to the HLB-archive.  Open the folder and click on img’s and transfer all img’s to the img archive on HLB-archive. When you have finished copying and pasting, check that the transfers have been successful and then delete the data from the data stick. Then click on the green arrow with the card again to remove safely.

Flag Values:

Males:

  1. Weight >32g
  2. Body Fat Composition less than 12% or greater than 21%
  3. BMD .0432-.0537 g/cm2 @ 12 weeks, .0435-.0503 g/cm2 @ 18 weeks, and .0449-.0565 g/cm2 @ 20 weeks
  4. BMC .358-.609 g @ 12 weeks, .356-.678 g @ 18 weeks, and 391-.702 g @ 20 weeks

Females:

  1. Weight >34g
  2. Body Fat Composition less than 15% or greater than 29%
  3. BMD .0437-.0501 g/cm2 @ 12 weeks, .0435-.0503  g/cm2 @ 18 weeks, .0445-.0505  g/cm2 @ 20 weeks
  4. BMC .344-.464g @ 12 weeks, .385-.513 g @ 18 weeks, .417-.489 g @ 20 weeks

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