Pixel shifting is a process used in conjunction with Mask Subtraction to correct for movement of the patient between exposures, so as to give the best alignment and therefore the best masking of fixed structures possible. In general, there needs to be a different shift factor for each frame in an image (if there has been movement between the mask and the image frames, then there is also likely to be movement between the image frames!
The Planar Configuration attribute (0028,0006) is only used in DICOM colour images, and specifies how the pixel data are arranged.
A Presentation Context may be considered as a negotiated “sub-channel” with a DICOM Association through which the Application Entities have agreed to exchange information.
A proposed presentation context consists of
A presentation context ID (an odd integer <= 255, and unique within the association) A SOP Class or Meta SOP Class A list of proposed Transfer Syntaxes This is considered by the requesting Application Entity which either rejects it completely or accepts, in which case the list of proposed transfer syntaxes is replaced by a single accepted transfer syntax which is then used for all communications using that presentation context.
A Presentation State is an independent DICOM SOP Instance that contains information on how a particular image should be displayed. The Presentation State may contain label information(types of Label and Positions), windowing values, zoom value, scrolling (panning) values, rotations or any other visual display element that is defined within the DICOM standard.
However Presentation States contain no Pixel Data as they are intended for use with an existing Dicom Image.
Annotations DICOM Printing contains a specification for ‘Annotations’, but the terminology is very confusing, so this page is designed to explain the facility, and avoid misunderstandings.
When a FilmBox is created, it has 3 types of area, as in this diagram:
Black Areas where pixel data can be printed (Using N-SET)
Yellow nothing can be printed here
In general, the arrangement of the pixel data areas is defined by the Format string (e.
Printing "True Size" Images
We are often asked how to persuade a DICOM printer to print images (normally plain radiographs) “TRUE” size. This is normally possible (depending on the capabilities of the printer) but is harder than expected, as the DICOM standard requires most of the relevant attributes (pixel size etc.) to be removed from an image before it is sent to the printer :-( The problem is compounded by the fact that the default behaviour of almost all printers is “scale to fit” - fitting the image as best they can into the space available on the film.
Printing without using DicomPrint
Although DicomPrint object is designed to make printing simple and easy for developers to code, it is possible to use a more advanced DicomConnection (COM version) or DicomAssociation (.NET version) object to meet your special requirement.
The code below gives a starting point for those wishing to do this themselves
Private SOP class
A Private SOP Class is an object constructed and transmitted in the same basic way as an official DICOM SOP Class but with the contents defined by the creator of the private SOP class, rather than by DICOM. Typically a piece of equipment which uses a private SOP class will try to negotiate both a Private SOP class and an official DICOM SOP Class for the images they send to a PACS, on the basis that only a PACS from the same manufacturer will accept the private one, with everyone else accepting only the DICOM one.
Problems using DicomObjects.NET from VBScript
Following our first article about how to Host .NET Viewer on Web Page, people asked questions about using DicomObjects.NET from their VB/Java scripts.
We created this page to sum up some of the most commons problems, and we will continue to update this page should we get more questions/solution from our values users.
Objects doesn’t support this property or method Make sure you do NOT have a com ocx version of DicomObjects registered on your computer.
Product Licensing Overview
This page explains licensing structures and some of the frequently asked questions.
A “normal” DICOM Query, as part of the Query/Retrieve service, is used to ask about the patients, studies, series or images known to a Q/R SCP (normally a PACS). It uses the C-FIND operation (and was originally the only service using that operation, so this query service is often called just C-FIND, despite that fact that the C-FIND operation is also used for other services such as Modality Worklist).
Querying Patient Information by Modality
It is possible to query for Patient Information using a DICOM C-FIND operation with Modality as a filter, in order to find all patients who have ever had a series with a particular modality. This can be done by a STUDY root STUDY level C-FIND query. A DoRawQuery(QueryDataSet) method in COM version of DicomObjects or Find(QueryDataSet) method in .NET version is required with ModatiesInStudy field (0008,0061) being explicitly added as a modality to search for.
Radiotherapy objects were DICOM’s first foray into non-image Composite Instances - i.e. data to be stored long-term without pixel data. They are stored, handled, retrieved etc. exactly the same way as images. There are 7 radiotherapy objects:
Radiotherapy Image Radiotherapy Dose Radiotherapy Structure Set Radiotherapy Plan Radiotherapy Beams Treatment Record Radiotherapy Brachy Treatment record Radiotherapy Treatment Summary All these can of course be handled by DicomObjects, but only the Image and Dose can be displayed in a viewer.
There are three types of Refresh in DicomObjects:
This routine fires automatically when any of the following display settings gets changed:
RegSvr32 is the Windows utility for registering ActiveX/COM controls such as DicomObjects ocx.