Calibrating measurements in Panoramic images is not suggested. Panoramic images are 2D distortions of a 3D image, which makes distances inconsistent throughout the x-ray. Apteryx recommends measurements be taken using intra-oral sensors for accuracy.
Calibrating measurements for Phosphor Plate images will only be successful for a single image and will not apply to all scanned images. This is because the calibration is based on resolution (eg 1070 x 790). Scanned images may have a slight rotation when dropped into the scanner resulting in an inconsistent resolution (eg 1071 x 789 or 1069 x 791).
Calibration factors exist based on these
Manufacturer
Model
Serial Number
Instance pixel width/height
if a user calibrates a Schick/Maximus Gen2/SN12345/Width=1708 pixels/Height=2400 pixels
then an image with the following dicom metadata shares the same calibration factor (ratio)
Schick/Maximus Gen2/SN12345/Width=2400 pixels/Height=1708 pixels
Calibrating a sensor is done by taking an image of an object of known size and using that image as reference for Apteryx software to measure against. Apteryx recommends using a coin as the reference image, and supplied below is a sizing chart for US and Canadian coins.
Open Apteryx under a Test Patient.
-
Capture an x-ray on the chosen test patient in XVCapture of an object of known size on each brand/size of sensor.
Example: If you have 2 Tuxedo A Size 2 sensors and 4 Tuxedo A Size 1 sensors, you will need to capture 1 Tuxedo A Size 2 image and 1 Tuxedo A Size 1. You do not need an image from every single sensor, just one for each size of each brand of sensor.
Click on the thumbnail of the image on the left-hand side.
Select the image in the middle of the screen to bring up the Image Edit bar at the bottom of Apteryx
-
At the bottom of the window, click the Label button, then select Calibrate
Left-click on the starting point of the measurement (in the example of a coin, it would be one edge). Move your cursor in a relatively straight line and left-click on the end of the measurement area.
-
The Calibrate Measurements prompt will populate with a reported distance in millimeters. Fill in the correct known distance (in millimeters).If using a US or Canadian coin as your object of known size, a chart showing the diameters of these is below.
Click Save.
Repeat steps 2-7 for every sensor of unique size and branding.
Size calibrations are global settings and will apply to every workstation using the calibrated install.
US Coin |
Penny |
Nickel |
Dime |
Quarter |
Half Dollar |
Dollar |
Diameter |
19.05 MM |
21.21 MM |
17.91 MM |
24.26 MM |
30.61 MM |
26.49 MM |
Canadian Coin |
1 Cent |
5 Cent |
10 Cent |
25 Cent |
50 Cent |
Loonie |
Toonie |
Diameter |
19 MM |
21 MM |
18.03 MM |
23.88 MM |
27.13 MM |
26.5 MM |
28 MM |