Not pixel to pixel or 100%, I need real bone size. I must measure some distances from the computer screen.
If you want to measure distance in DICOM image, you should use measurement functionality of your DICOM viewer, ususally there is such tool (could be called 'measure', 'ruler' etc.) It will give you 'real' distances in mm or cm, and the measurements will have the same results regardless of 'zoom' setting. If the bone is 10cm long at '10%' zoom, it will be also 10cm long at '200%' zoom - the reading will be the same. It does not make sense to use real, physical ruler on the computer screen.
Unfortunately the measured dimensions, regardless of the method, may not be always correct due to different magnification of different objects in the image. If you measure distances within CT or MRI scan, it will be OK. But if you do distance measurements in radiography, mammography, or any other planar imaging technique, you can only measure length of an image of the bone, and not of the bone itself - see the image:
http://www.dartmouth.edu/~humananatomy/figures/chapter_5/5_1_files/IMAGE002.JPG
Depending on location of the bone with respect to the film, magnification of its image will be different, and no software will help you for that.
P.S. Hmmm, dopiero pod koniec zauważyłem że mogłem pisać po polsku :-)
Hello.
To me your question is not very clear. Do you have DICOM images obtained from any medical equipment (Rx, CT, MRI)?
Anyway I put two suggestions here.
I recommend you to use a DICOM viewer, such as eFilm. This tool is very useful as it also allows you to organize studies of patients and search and all other functions of a PACS.
Another simple tool is free software "ImageJ" (http://rsbweb.nih.gov/ij/download.html). With the can you get values in cm or mm. It has all the potentials above but it is simple and very useful. Best regards, Evelio
Maybe you could attach a sample image here, so we would better know what we are talking about?
Magnificent, is a good idea. Put you any DICOM image and we will recommend how to proceed. Just make sure it is actually DICOM. We measure it and tell you for your reference. Greetings to all and good weekend.
I think you can easily write out the size of each pixel, than any physical distance in the image can be calculated by multiply the pixel length by the pixel size.
Oskar, if your question refers to X-ray projection (radiographic) images please be aware that any measurement in the DICOM image refes to the projected size of the bone (on the detector). To get the real bone size you have to take into account the radiographic magnification, which depends on the distance of the bone from the detector and the focal spot -detector distance. Very often the exact distance of the bone is not known (since it is inside the body) so the size determination from the image has an uncentainty.
edit: I see now that Witold has given this comment already ;-)
https://www.facebook.com/PolskaAntropologiaFizyczna/photos/a.649856018370508.1073741828.612587498764027/1026357897386983/?type=3&theater
Our software Checkpoint can load DICOM and provide 3D measurements of bone surfaces by placing landmark points onto the surfaces:
https://www.stratovan.com/products/checkpoint?utm_source=rg&utm_medium=ans&utm_campaign=dcmv2
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