Spine SRS

Table of Contents

Pre-Planning Information

Preparing for Spine SRS with Image Fusion

When performing Image Fusion in preparation for Spine SRS, you must define a unique planning CT to fuse to other available image sets (e.g., MRI). The following conditions apply to the image set used for dose calculations:

  • There must be exactly one image set with modality CT.

  • The CT image set must be supine.

  • The CT image set must be head first.

  • The CT image set must not be tilted.

  • There can be other image sets with modality other than CT, but these must be fused to the CT image set.

  • All image sets must be fused.

Preparing for Spine SRS with Anatomical Mapping

Use Anatomical Mapping to automatically create segmented objects (e.g., organs at risk) as well as to review and refine/reshape these objects.

Anatomical Mapping automatically defines: Type = name of the organ and Role = Undefined.

Preparing for Spine SRS with SmartBrush

For Spine SRS to operate, contour the metastasis to be treated. SmartBrush automatically defines: Name = Gross tumor, Type = Tumor, Role = GTV.

After the tumor is contoured, SmartBrush automatically creates:

  • The CTV and defines: Name = Clinical target, Type = Unknown and Role = CTV
  • The spinal canal and defines: Name = Spinal Canal, cropped, Type = Spinal Canal and Role = OAR
If desired, you can create a boost object within the outlined tumor, which must be defined as Role = CTV. Spine SRS automatically detects a PTV within a PTV or tumor as a boost and calculates the boost as a SIB (simultaneous integrated boost) plan.

Preparing for Spine SRS with Object Manipulation

If desired, you can create a PTV in Object Manipulation by adding a margin to the CTV.

Object Manipulation automatically defines: Type = Undefined, Role = PTV.

Finding the PTV and Boost

Spine SRS searches for the PTV and boost (if available) to treat in the following order:

  1. Role = PTV. If no fitting object is found, then

  2. Role = CTV. If no fitting object is found, then

  3. Type = Tumor.

  4. The software automatically detects a boost if it finds exactly one PTV completely enclosed within another PTV.

Changed Data

If you add, deselect or change any data sets (e.g., image fusion) or objects (e.g., tumor shape) belonging to the loaded treatment plan in the pre-planning Elements, the plan will be adapted to the changes. The above message warns you upon starting Spine SRS. Select OK to confirm and adapt the final RT plan to the latest changes.

Art-No. 60919-40EN

Date of publication: 2019-05-22