BoneJ 1.4.1 released

[Michael Doube]

Dear all,

BoneJ 1.4.1 is out and you can get it from bonej.org.

v1.4.1 provides bug fixes and performance enhancements to the new Ellipsoid Factor feature, bonej.org/ef, which was introduced earlier this year.

SMI is now able to display in 3D concave portions of surface meshes (in blue) and convex portions (in yellow) bonej.org/smi.

All changes are available to view in the Git repository:
https://github.com/mdoube/BoneJ/commits/master

Best regards,

Michael

[Ayman Mostafa]

Thank you for the great software.

- I'm trying to Get an estimate of the "actual" BMD of the femurs on standard radiographs, is this possible? I have published a paper that measured the gray scale value (bone contrast) immediately and 4 months after total hip replacement using ImageJ, and was thinking if there is anyway to get an estimate of BMD on radiographs?

Thanks
Ayman

[Michael Doube]

Dear Ayman,

The short answer is no.

The radiograph is recording an integral of point-by-point X-ray attenuation values along the paths that the X-rays took to arrive at that spot on the final image. Thus, if the X-ray went through more material, it could be equally attenuated as an X-ray that went through less, but more highly attenuating, material. I hope that makes sense. It is like trying to measure the concentration of dye in a glass of water by recording how much light gets through it, but without knowing the size of the glass. (This is why those biochemists' cuvettes are all so standardised in size, shape and materials).

You can measure total X-ray attenuation by comparing it against a phantom such as an aluminium step wedge, but this measurement carries the heavy caveat that you know nothing about axial thickness and therefore is of extremely dubious value in the determination of BMD. If your radiographs do not contain a phantom they are uncalibrated and cannot be used for quantification of grey values at all.

These are the basic reasons why people who are interested in measuring BMD do so with pQCT or with DXA (though these also both have some important limitations).
https://en.wikipedia.org/wiki/Quantitative_computed_tomography
https://en.wikipedia.org/wiki/Dual-energy_X-ray_absorptiometry

In a research setting, if you have isolated samples, you can also measure density using physical methods like Archimedes (using buoyancy & displacement) or filling all spaces with gas (volume) and measuring weight with a high-precision balance.

Best regards,

Michael