SGRT Forum

Our clinic looking for guidance on how to better manage our breast patients.  Currently, we setup for treatment using the DICOM surface followed by an orthogonal image pair.  If the patient is a 3/4 field breast, has a head turn, or history of poor arm positioning we will take a Treatment Capture to correctly position the head and arm.  This is easy for us to do if the DICOM surface runs through the nose (traditionally we have only scanned to mid mandible).  We've found the nose is a good landmark to assist in head positioning.  Also, this gives us plenty of arm surface for positioning.  Even though we can improve positioning by increasing the simulation scan length and combining the DICOM surface with the Treatment Capture we are concerned about the increased dose during simulation.

Does anyone have any data, standards, or recommendations for how these patients are to be managed?  Is there a best practice?  Or is it just physician/physicist preference?

Hi Kenny

Could it be so that when there is errors in the arm position with the DICOM, you simply acquire new reference surface for the setup when you may see the entire arm. New reference surface should be taken with the accurate patient position- and posture after online corrections, when there was not any new errors in the images causing new systematic errors.

With the AlignRT, with the DICOM, in FB breasts, where the scan was acquired beginning from the mandibula, we have had surprisingly good reproducibility in the shoulder joint position. Systematic error is still larger than the random error indicating often the need for the new reference surface concerning (also) arm setup. In DIBH, where we always acquire new reference surface for the FB setup, results are also good nowadays. In both cases  we setup the arm with the aid of treatment capture. In comparison to arm ROI, we have found that treatment capture is better in the results which demonstrates shoulder joint accuracy.

I would not acquire CT-scan for breast patients which goes through the brains, since there is in problematic arm positioning cases an other way to solve the problem, which is a new reference surface for the setup.

Marko