Following a question on our facebook page about calculating gestational age on the TH80v, here are some images to help you find the buttons.

The DIS, C/A and PW buttons are the 3 you'll need.

Once you've frozen your desired image, press DIS to enter into measurement mode, shown here:

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Set your measurement points using the trackball, pressing enter to set each point.

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Use the C/A and PW buttons to select the appropriate animal and gestational age calculation method.

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For example, pick the DOG_CRL option, shown above, if you are scanning a canine and wish to use the crown rump length method.