Lookup Tables

There are 4 types of lookup table (LUT) which can be found within DICOM images are part of the standard, and one further type which exists in DicomObjects. 

Palette Colour LUTs

These are only used when the Photometric_Interpretation is PALETTE COLOUR. They can be 8 or 16 bit, and 3 copies exist, one each for red, blue and green.

Secure Connection with DVT Simulator

If you are testing DicomObjects's Secure Connection Functionalities and wish you to use DVT simulator as the tester, then it is very easy to do so as long as you have the DVT-trusted ".p12" file (we are using the one that comes with DVT here):

Dim sec As New DicomServerSecurity
Dim CertBytes As Byte() 
CertBytes = System.IO.File.ReadAllBytes("C:\Program Files\DVT\certificates\SutSelfSigned.p12")
sec.Certificate = New X509Certificate2(CertBytes, "dvt")
sec.ClientAuthentication = False
server.Listen(104, sec)  ' server is a DicomServer object

TCP limitations in DICOM

DICOM uses TCP (transmission control protocol) as its underlying network transport layer, and despite its widespread and generally successful use around the world for most Internet use, TCP does have some significant limitations. In practice, these limitations are extremely rarely encountered in real life, but they can sometimes be seen in stress test scenarios, and it is then important to to be able to distinguish between those failures which are due to the DICOM application being tested, and those which are intrinsic to TCP itself.

How to Specify the Cine Display Rate

There are multiple ways of specifying Cine Rate (Multi-Frame Display Speed) in DICOM, in two categories:

The actual acquisition times of the frames

There are two ways of specifying this, equally spaced or arbitrary, and the choice is defined by attribute Frame Increment Pointer (0028,0009), which will point at one or other of the following attributes:

Creating Secondary Capture Images

Any 'valid' Dicom Image is a conglomeration of Pixel data and several mandatory data attributes. To generate a Secondary Capture (SC) Image from existing non-Dicom image then all that is required is to load the required image into a DicomImage using the import function and then adding on the appropriate attributes. Dicom Objects will automatically take care of all the attributes relating to the pixel data (Group 0x0028).

Patient Orientation

Description Value in (0020,0020) Image
Original R\P
Rotated 90° A\R
Rotated 180° L\A
Rotated 270° P\L

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.

Hierarchical SOP Instance

While DicomObjects can not create a Dicom Hierarchical SOP Instance dataset collection directly, however it can do much of the work for you. A Hierarchical SOP Instance Dataset collection are similar in structure to a DicomDir which DicomObjects can create automatically. Hierarchical SOP Instances are primarily used in the creation of Key Note Objects. The Structure of the Hierarchical SOP Instance is Study - Series - Instance (NO PATIENT)


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