UUUU.3.2.2 Radiofluoroscopy

UUUU.3.2.2 Radiofluoroscopy (Current)
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Radiofluoroscopy (RF) systems perform radiography of almost any anatomy or organ system, as well as fluoroscopy of the gastrointestinal system, genitourinary system, hepatic and biliary system, spinal canal, joints, lungs, and others. Often, fluoroscopy involves real time imaging of the flow of radio-opaque contrast material (e.g., barium or iodine) through these organ systems.

The equipment always includes a fixed rad/fluoro system, typically capable of acquiring fluoroscopic, acquisition/cine, and radiographic images (and sometimes even tomosynthesis images). This system can be in 1 of 2 possible configurations:

X-Ray source below patient table and image receptor above table
X-Ray source above patient table and image receptor below table

In both configurations, the X-Ray source and image receptor are connected to each other via a gantry. For most exams, the table is horizontal with the patient lying on the table. The table can often angulate even to the point where it is completely vertical for some studies (e.g., swallow studies).

An additional ceiling mounted X-Ray source may be present in the exam room. This X-Ray source may be used for:

radiographic imaging with a DR or CR image receptor that is free floating or mounted on the side of the patient table
radiographic imaging in conjunction with a table bucky or wall bucky that can accept either a DR or CR image receptor. The table bucky and/or wall bucky may or may not be present.

In all these procedures, the usage, location, and the technical characteristics of the X-Ray Sources and Image Receptors (if they are known) are typically communicated electronically to the system generating the RDSR. Some systems may have limited communication related to the Image Receptor (e.g., CR systems), while the mechanical data related to the rad/fluoro gantry is generally communicated (e.g., positioner angles/column angles).

A general rad/fluoro procedure workflow is as follows:

The study and procedure start,
1. Patient and procedure information is provided to the equipment by the DICOM Modality Worklist or manually entered by the operator.
2. Equipment settings like protocols, patient position relative to the table, etc., are then provided to the equipment by the operator.
During the procedure, X-Ray exposures are performed.
1. The irradiation generation of one X-Ray source during the time between X-Ray ON and OFF is considered one Irradiation Event.
2. The rad/fluoro system can acquire lower dose fluoroscopy exposures as well as higher dose RF exposures.
During the procedure, images are generated.
1. One Irradiation Event can result in a single frame 2D projection image or multi-frame 2D projection images (a "loop" acquired at some frame rate) that is/are typically displayed in real time on the system.
2. The rad/fluoro system can acquire lower dose fluoroscopy images that may or may not be stored locally (user selectable option) as well as higher dose RF acquisition/cine images that are always stored locally. The RF images can be single frame or multi-frame.
3. The rad/fluoro system can acquire DX/CR 2D radiographic images. The ceiling mounted X-Ray source (and associated image receptor) can acquire DX/CR 2D radiographic images. These images may be stored locally, or as may be the case for CR detector, on an associated system. The DX/CR images are single frame.
4. The image(s) stored locally during one procedure step may be exported as a DICOM series.
The procedure ends.
Several/many procedure steps can be performed during the study.
The study ends.
Following the study, one or more RDSR Instances are created from the data collected during the procedure .
1. The scope of accumulation of the RDSR indicates the period of irradiation reported in that RDSR instance, e.g., the Study, the Series, the Performed Procedure Step, etc.
2. If the system does not know about the Image Receptor, such information is not stored in the RDSR, and may be part of a separate RDSR from the associated system. If the mechanical data related to the rad/fluoro gantry is known it may also be included in the RDSR.
Subsequent dose analysis is performed.
1. Dose analysis is based on the information of the Irradiation Events contained in the created RDSRs.
2. Irradiation Events and images are often one to one, but there may be Irradiation Events with no images (e.g., deleted images). For this reason, dose analysis is driven by the Irradiation Events, not by images. See Section UUUU.4.1.4 for the importance to use the Irradiation Event UIDs in the RDSRs.

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