RT Image Module¶

The RT Image Module (included from the RT Image IOD) describe RT-specific characteristics of a projection image. The image described by these attributes must be a radiotherapy image acquired or calculated using a conical imaging geometry.

The module consists of the following "functional" parts:

• Image description: Here are some restrictions to the General Image Module, e. g. for Bits Allocated/Stored. Also one can find here some labels for the image.
• Radiation machine description/setup: Some information about the radiation machine used, e. g. "Radiation Machine Name"
• Referenced RT Plan: Exactly one RT Plan, which is associated with this RT image, can be referenced. Also a specific beam inside the associated RT Plan object can be referenced as well as the fraction number inside the plan. (TODO: What is Start/End Cumulative Meterset Weight? Describe)
• Exposure Sequence: Large sequence describing the exposure parameter sets (one set per frame in RT image) used in generating the image.
• Numerical machine setup information: Contains (fully optional) information about Gantry Angle or e. g. Table Top Position.
  All numeric beam data parameters recorded with the RT image are from the time during that image acquisition and do not have to correspond to an actual RT Planinstance that is created for a patient.

In the following sections all of these five functional parts are described in more detail.

Part 1: Image Description¶

TODO

Part 2: Radiation Machine Description/Setup¶

TODO

Referenced RT Plan¶

TODO

Exposure Sequence¶

Introduces sequence of Exposure parameter sets, corresponding to exposures used in generating the image. The sequence can contain one or more items. Each item included references one frame stored in the RT Image IOD instance.

• The sequence item first contains radiation information (e. g. "KVP - peak kilo volatge output (kV) of X-ray generator used to acquire image" or "Exposure Time - Time of X-ray exposure (msec)").
• Next is the Beam Limiting Device Sequence which contains information about any beam limiting device (collimator), ie Leaf/Jaw Pair, which limited the beam for a given exposure.
• Electron Applicator Sequence: This sequence describes the electron applicator (if there is one) associated with that beam (some defined terms for "square electron applicator, circular electron applicator, stereotatic applicator, etc.)
• Next after that sequence there follow the Block Sequence, which similarly describe any blocks associated with that beam (e. g. Block Thickness, outlines of block including position, etc).

Numerical machine setup information¶

Contains (fully optional) information about Gantry Angle or e. g. Table Top Position.