UID Rules

There are several rules to be followed when making UIDs, and this page is a useful summary

Hounsfield Units

Hounsfield Units (HU) are used in CT images it is a measure of radio-density, calibrated to distilled water and free air.

HUs can be calculated from the pixel data with a Dicom Image vir two methods.

The first (and harder) method involves using the Slope and intercept value from the Dicom image and applying it to a target pixel.

HU = m * P + b

where: m is the Dicom attribute (0028,1053) "Rescale slope" b is the Dicom attribute (0028,1052) "Rescale intercept" P is the value of that particular pixel in the pixels array.

Get Patient Info from DICOM Print

Is it possible to get patient information from DICOM Print?

Some developers, faced by systems with DICOM Print and no DICOM C-STORE have wondered whether that "DICOM output" could be used to capture images to store in a PACS.

Conversion from the COM version of DicomObjects to the native .NET version

Conversion of a DicomObjects ActiveX/COM project to .NET looks initially daunting, but in fact is quite simple, and for those using any of the complicated ActionComplete/ActionUpdate mechanisms and asynchronous DicomConnection objects will find that the resulting code is lot simpler and easier to maintain after conversion. As ever, we are happy to help with any conversion issues.

How to Import PDF to DICOMPDF

Import general PDF files and turn them into DICOM PDF format is not much different to import other file formats, i.e. windows Bitmap and Jpeg images.

Based on the DICOM supplement 104, we made two small programs (VB6 using COM version and C# using .NET version) which demonstrate what attributes are needed for making a valid DICOM PDF file.

DicomObjects performance when running in background thread

To improve the performance of DicomObjects when running in background threads (instead of the main thread), setting the "ThreadModel" registry to "Apartment" greatly improves the speed. Versions of DicomObjects of the form (the 9 indicates compilation with Visual Studio 2008 - aka VS9) create these keys automatically when registered automatically (whether using RegSvr32, or an installer etc.), but for older versions of DicomObjects, manual addition as below is necessary.


UIDs are fundamental to DICOM and have many uses, including there being a unique one for each SOP_Class and for each Composite_Instance and each Normalised_Instance.

There are several rules for how a UID is constructed:

Remove and Re-Import DicomObjects ActiveX in Delphi

Remove DicomObjects Completely From Delphi

  • Open up the dclusr.dpk file, if that’s where you installed DicomObjects:

  • Click on Remove button from the top menu bar. And choose DicomObjects_TLB.dcr and DicomObjects_TLB from the "Remove From Project" Window:

Barco Problems

It is a sad fact of life that “specialist” cards such as medical greyscale cards have often got a lot more undetected bugs than “consumer” cards which are tested on a far wider range of systems, and this particularly affects their DirectDraw driver implementations. Barco monitors seem to have the most problems, but the same effects (e.g. white screen) can be seen with others also.

There are 4 suggestions:


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