SGRT Forum

SGRT Community wrote: ↑Thu May 09, 2024 9:25 am

Do patients often move outside of the threshold pausing the beam?

not too often, but it certainly does happen. some patients more than others obviously. if they do move the fairly often move back into tolerance

SGRT Community wrote: ↑Thu May 09, 2024 9:26 am

How did you increase confidence of staff when moving towards tattoo-less surface-based positioning?

just understanding of how it works and practice. it is pretty self evident how sensitive it is to motion through just a short use

SGRT Community wrote: ↑Thu May 09, 2024 9:26 am

Since the Ct table isn't the same as the couchtop in the linac: can you put a couchmodel in MapRT?

Yes, when VisionRT set up the system for you they create virtual rooms with the linacs in your department, i.e. Varian or Elekta. This includes the couch and the gantry (with and without imaging equipment). They can also make models of any accessories that are used on treatment but not on CT, e.g. the 'couch extension H&N board' used on Varian machines.

SGRT Community wrote: ↑Thu May 09, 2024 9:24 am

Have any centres used AlignRT to go mask free for H&N patients?

We are in the process of moving to shoulderless masks for all patients and using postural video to monitor shoulder position. We are also looking at faceless masks.

SGRT Community wrote: ↑Thu May 09, 2024 9:19 am

Can you comment on what percentage of patients are fully using the AlignRT workflow.

We are using AlignRT for 80% of our patient population. Only for head&neck cancer patients with closed thermoplastic masks we don't use AlignRT (which is about 20% of our patient population). We use AlignRT for our electron patients, although there are exceptions (e.g. on the scalp where there is no visibility).

SGRT Community wrote: ↑Thu May 09, 2024 9:21 am

How does AlignRT tackle center couch during CBCT for DIBH treatments?

For treatment in DIBH where we need to use the center couch we use the following workflow:
1) setup in FB
2) practice the DIBH
3) from the linac console, instruct the patient in DIBH, then perform the center couch shift (in DIBH) and take a new reference after the shift (in DIBH)
4) have the patient exhale and recuperate
5) acquire the CBCT in breath-hold base on the captured reference.

We find that this workflow works well but does require some extra care from the RTTs: we have had patients exhale because of the sudden large couch movement, so RTTs need to provide more instructions to the patient.

SGRT Community wrote: ↑Thu May 09, 2024 9:23 am

Have you ever had to implement set up contingency plans for tattooless patients due to AlignRT failure?

We have set up a contingency plan but we have never had to use it. The basic idea would be: setup patients 'visually' based on photographs we acquire during the CT-sim (e.g. hand position in the arm support). Then we would go to the acquired couch position (we do this for all patients on TrueBeam during the first fraction). Then we would acquire a CBCT and continue on that.

SGRT Community wrote: ↑Thu May 09, 2024 9:26 am

How did you increase confidence of staff when moving towards tattoo-less surface-based positioning?

We initially thought about implementing tattooless incrementally (starting with prostate cases) but then reconsidered as this would possibly create more confusion than it was worth. So instead we had a few information sessions with RTTs (after the decision with a small team was made to go for tattooless). Then we simply stopped tattooing and barely noticed any effect on the linacs...

During our preparation we did an extensive risk analysis to see if there were still parts of our workflow that needed to be adapted. eg. we now place the user origin in fixed locations in the body, and we try to use anatomical reference points such as the bellybutton (in case we would have a breakdown of AlignRT, see my other answer for that).

SGRT Community wrote: ↑Thu May 09, 2024 9:28 am

Physics: When commissioning SGRT and Workflow, was it complete physics lead or it had pre-treatment and treatment Radiographer involvement?

When we installed the systems (5 years ago) it was completely physics led. We did several checks eg. stability with lights on/off, beam gating, E2E test etc. We also set up all protocols and ROI instructions for the RTTs. At that point we also did not have anybody in the department with prior experience with surface scanning. If I were to implement a new system today, I would include some RTTs with experience. They work with the system everyday, so they know which ROI works best for which indication.

SGRT Community wrote: ↑Thu May 09, 2024 9:29 am

Do you have "key-user" RTT's?

We have an 'AlignRT RTT team'. They are volunteers with an extra interest in AlignRT. Everyday one of the RTTs is on call and they do all the available imports that day (we use Varian's CarePaths with an 'Import task'). Usually this RTT does also other non-linac related tasks (eg. draw blood or wound treatment). They are also the first line of contact for other RTTs when there is an issue on the linac.