Introduction to DICOM

DICOM is a standard that medical imaging technicians cannot escape. This series of topics focuses on the DICOM standard, which is intended to be understood by PACS administrators and software engineers.

 

Member of the ISO organization. As a standardAccuracy and universality of expressions, Wording is very cautious. This has a secondary effect: something that was originally quite clear. After using its noun system, it became very vague.

 

IOD (information object definitions)

-"Class" is a concept in object-oriented programming ). For example, the rectangular class has two attributes: length and width. According to a class, you can define a specific object and assign it length and width.

IOD is a class in the DICOM world. Also, these classes are well defined, such as patient IOD.

 

VR (value representations)

-There are many data types in the C language, such as integer and floating point. All data types in the DICOM world are not called data types for the purpose of "accuracy and universality of expression", but "numerical representation", that is, VR. Currently, there are 27 DICOM versions. Common VR services include:

UI-Unique Identifier (maximum length: 64 characters)

CS-code string (maximum length: 16 characters)

St-short texts

Many problems in DICOM communication are caused by the lack of thorough understanding of VR. For example, the DICOM standard limits the length of some VR services. If you do not comply with these limitations, the written software will have poor DICOM compatibility (for example, a uid is generated with 64 extra characters ). In addition, no matter whether the length (number of strings) of VR is limited, it must be an even number. In case of an odd number, fill in the space at the end. Naturally, problems may occur when communicating with other systems.

 

AE (Application entity)-What is the same as the application entity in the DICOM world? Yes, the term entity is tricky. In fact, it refers to a computer in a communication network that complies with the DICOM standard. If you are honest, you can install a virtual machine on a computer and connect it with DICOM. This is just two AE. Then you will understand why the concept is called Application entity instead of Application computer. The name "entity" means that you cannot be truthful. You can see how cunning the person with this name is.

AE can be either an imaging device (modality), A PACS server, or a QA client machine.

 

SOPs (Service-object pairs)-Service is the most basic concept in the client-server architecture. All the services in DICOM are essentially transmitted with IOD. When analyzing problems, we often consider them together to become SOPs.

 

Reposted from: tech Jati