Reducing Paediatric Radiotherapy-Associated Trauma, Positional Challenges and Additional Imaging Dose Through the Introduction of SGRT Technology

Samantha Stevens (00:03):

Thank you very much for that introduction. So my name’s Sam. As was said, we are going to be speaking about paediatrics and SGRT for our pediatric patients. So first of all, just a little bit about us. So we are from Nottingham Radiotherapy Center in the East Midlands in the UK. We have six linac’s altogether. So two of those. Linux has an exact track dynamic with six degrees of freedom capability with a third being commissioned hopefully in January. All being well. We have two linac at the moment with an AlignRT, again with a third hopefully being commissioned on another machine. We use AlignRT treat both our adult and pediatric patients at the moment. Our AlignRT journey started with our breast patients. We started with both free breathing and our DIBH patients.

Samantha Stevens (00:55):

It’s just a little bit about our pediatric service. So we have two pediatric clinical oncologists, two therapeutic radiographer, one of whom is me. And obviously, with the opening of the UK proton centers, our workload has significantly reduced, which tends to be now more palliative patients as well, which can be upsetting for the staff and for patients, obviously. But we still do treat quite a lot of our patients radically, particularly when they’re non-eligible for protons. So if they’re highly metastatic or we do have quite a few families that just prefer to stay port. If a family have like work life, you know, commitments, it’s not that easy for them to travel. So that can be up to them. And we also joint forces with the Birmingham service. So with the proton centres, obviously with our reduced workload we could struggle to keep our service up and running. So it was a good way of making sure that our numbers were combined and we could both offer services in both areas.

Samantha Stevens (01:50):

So why introduce SGRT for pediatrics? So obviously you guys know that the benefits of SGRT after this week will facilitate tattoo list radiotherapy, which is one of our main goals in our center. It’s reducing overall trauma not only for the patients but also for the families and the staff. Trying to tattoo a child, particularly away is absolutely horrendous and I can vouch for that. But also, it’s not just like the short-term trauma of upsetting the child and causing them the pain; it’s the longer term for the families when it’s a reminder when they look at those skin marks and think about what treatment they’ve been through. So as a center we actually already use open face masks. Usually three points for our brain patients. But as you can see on the table we had a little look back at some of our brain patients, and we were re-imaging them quite a few times per fraction, which tended to be due to rotation issues. And I’ll go on to talk about those a little bit more in the next few slides.

Samantha Stevens (02:48):

So what we did from thinking about SGRT being a positive for our pediatric patients is an audit to start with. So we compared an AlignRT to our 3D cone beam function. So we use XBI. So we compared the translations and rotations from both systems, and we looked at four body patients and four brain patients. We used standard setups to start with. So for the body patients we tattooed them. And for the brain we would just use our open face mask with the reference points. So don’t be alarmed by the amount of numbers. So this is just a very small snapshot of one patient and the data that we were trying to record all at one time. This is typed up, but we actually did it by hand whilst the patient was in bed. So if you think about the time pressures and things, it was quite stressful but we managed to get there.

Samantha Stevens (03:38):

So results for the brain patients that we were seeing are that so this graph on the right are the individual data points for some of our brain patients and it compares the difference between AlignRT in 3D cone beam as you can see, for the vert, lat and long it matches really well. For the pitch there is a bit more of a difference. We weren’t really surprised to see this because we know that our pediatric patients were on a lot of steroids. And we, they do suffer with significant swelling. I think if we repeated this or phase one part of our audit now with how we’ve amended the ROIs, we probably wouldn’t see such a difference. We’re not going to do that so we’ll never know, but I think we probably would.

Samantha Stevens (04:21):

And for the body, there’s a greater spread over all axes. But actually, the differences were less for the body. Again, we were kind of expecting this, we know with our pediatric body patients especially the ones under ga that they suffer from a lot of contour change. Paediatricians do not have much topography. So it is tricky to get the ROI right and it’s definitely been a learning curve, which Molly will speak about later. But our overall results between brain and body showed that actually we only had a millimeter or less translational and a degree or less rotational variation between cone beam CT and AlignRT. So we decided the SGRT was safe to use as our primary setup tool.

Samantha Stevens (05:09):

See some of the considerations from phase one of the audit. Sam’s already mentioned a little bit about contour change. It was a limited sample size. Obviously, we don’t get that many patients through and we were comparing multiple different body sites to one another so we just needed to take that into consideration. The risk of transcription error and we were taking down a lot of values all at a short amount of time. And with the ROIs we were learning and really, we are still learning. One of the, probably the biggest, considerations that we noticed with the patients under general anaesthesia, we were really struggling when they used a full LMA, the laryngeal airway. So the tubing and all the wires and everything were really interrupting our deltas and causing quite a bit of havoc. And then the last consideration, so dignity, obviously, it’s just as relatable for adults but normally for the younger patients as well, it’s a really, really tricky topic. So especially when we’re treating their pelvis, it was just trying to work around what was the optimal ROI to make sure that they also are kept.

Samantha Stevens (06:06):

But since phase one, we’ve moved to phase two of our audit and we are now using SGRT as our primary setup tool. So we are still tattooing our patients just because we’ve only got two systems at the moment. So if there was a fault we wouldn’t have a backup machine. But we are setting straight up to isocenter for our body patients using AlignRT and for the brain patients, we are pre-positioning them now. So before we apply the mask and that really is improving our rotations before we scan them, we’re now re-recording our re-imaging frequency. And also the reason for re-image. So, try and keep an eye on contour change if there’s anything we can try and do about that. And then probably one of the biggest highlights has been that we’ve been able to convince our GA team to use nasal cannulas, the nasal specs instead of the full LMA. Obviously, we’re safe to do so for the patients, but that’s been a massive improvement in the camera occlusion.

Samantha Stevens (07:00):

Okay, so our first case study, this was a 7-year-old girl and we were treating whole lungs for metastatic urine sarcoma. She was awake, she was in initially part of the phase one audit. So we were just writing down the results that we saw on a AlignRT and comparing them to the results that we saw on the cone beam ct. After the first two days we realized we could no longer ignore the yore that AlignRT was showing and that our imaging was agreeing with. So the first couple of days we did re-image her because we had to adjust her hips. So for those who aren’t used to looking images like this, the green is the cone beam CT and the pink is the planning scan. So you can see that her hips are too far over to her left. So it wasn’t ethical to continue not using AlignRT as our primary setup tool for this patient. And then when we did use AlignRT, obviously, it removed the yaw.

Samantha Stevens (07:49):

So our second case study is a little boy who’s come to us for treatment a couple of times. So he first came last year with DIPG and he had 13 fractions. He started a week before our phase one audit started. He was really suffering with swelling from steroids. We were having to re-image him a lot during treatment. Bear in mind that these patients were already using open face masks because they were under ga. So when we started using AlignRT, we were like, we have to move this boy onto AlignRT machine and start using AlignRT for him. We moved daily imaging, and following the advice from Vision RT, we did pre-position without the mask on. And it significantly improved things for us. He then came back for treatment at the beginning of this year and we went straight to the phase two party.

Samantha Stevens (08:33):

The audit we’re pre-positioning him. So some image examples you can see from the first image that there’s a significant role on that left-hand image. But actually, when we used AlignRT, the role was eliminated. And then the second course of treatment you can see how swollen his cheeks are. So we were really concerned when he came back. We thought we were, were going to have an awful lot of problems with him and actually it was brilliant. There was much less reimaging; we only had to reimage him on his last fraction and that was because of steroids and cheek swelling. Again, I think now knowing what we know now, our ROI may have eliminated the need to reimage on that last fraction.

Samantha Stevens (09:19):

So these are some of the phase two audit examples, very quickly. So we had a 6-year-old boy who was under ga. We used the nasal specs on him, so we avoided camera occlusion. He was our first pediatric that we went straight to the isocenter on, completely ignoring tattoos and we didn’t have to re-imaging once, which we think is a massive success. And then similarly, we had a patient with DIPG again GA with nasal specs. And she was a reradiation case as well who had had previous reimaging, and once again, we didn’t have to re-image once when she was on phase two of the audit.

Samantha Stevens (09:53):

So we think it’s really important not just to stand here and talk to you about all the cases that have gone really well since we’ve used AlignRT and actually talk to you a little bit about when it didn’t work so well. So this got, this was our, her ROI, she was an extremely long volume monitoring of the whole lungs and abdomen. And you can see at the top of the image there, the laser’s not working very well, sorry that her spine had moved off. Now, if you compare where the image had gone off to our ROI, you can see why that may have happened. She was on phase two part of the audit. So we were going straight to isocenter, and we for three fractures in a row had to re-image to reposition her. The patient, unfortunately, was diagnosed with c diff and flu after her first fraction and she missed a week of treatment.

Samantha Stevens (10:36):

So when she came back she had significant contour change. She went from having nasal cannula, she was GA having the nasal cannula to LMA. So a lot of things had changed from that first treatment fraction. We then changed our ROI to include a little T across the top. And so yeah we got there in the end. So I think the big message is even when it doesn’t work, you can use your imaging to inform your ROI delineation which is what we did with this case. And we also removed sections of the ROI that no longer work so well now that we have the LMA. It really evidenced how quickly staff can lose confidence with the system. We have all used tattoos for years and years and years and the first thing people said to us was, we’re just going to go back to tattoos. And we were like, well tattoos as iffy and inside aren’t going to help with your up at neck. Let’s you know and try using the imaging to inform our ROI. So I think it really highlights how important it is to bring staff along with you with the decisions that you are making and why you are choosing not to go back to tattoos and to continue to trust the AlignRT system because cases like this, whilst they’re tricky in the long term, do actually really, really help with staff confidence.

Samantha Stevens (11:56):

So we’ve just treated our first cranial spine. He’s still on treatment at the moment. The way we plan our crania is we have three separate isocenters, the head, T spine and L spine. The clinicians are the main reason we haven’t gone tattooless yet. And bringing in this new technique there was no chance we were going to be allowed to use AlignRT as our primary setup tool, but we did manage to convince them to let us use it as an aid to set up the patient. So five point immobilization mask. I think the talks today really highlight why we might be getting some of the issues that you’ll see with this. And it’s a tricky ROI we need to know there’s no pitch in your head and L spine. So what, what do we do with it?

Samantha Stevens (12:39):

I mean in hindsight, we probably should have spoken to the Vision RT team before we did it but we didn’t. So do you split it? Do you do it all in one? We actually did sort of two and two and two. The doubt has really struggled with three ROIs. It just couldn’t see it all. So two ROIs together showed pitch which we could correct for, which was great. We can’t extend the ROI superiorly because of the five point mask. And the image showed your at the upper T spine. So I think with this case study as well as the previous scale that we showed you where we put the T across the top with the ROI actually that’s really good evidence to suggest that we maybe shouldn’t be using five point masks anymore and that we should either be going to three point and faceless or no mask at all eventually.

Samantha Stevens (13:23):

The key issue is something like this. So is patient dignity. How’d you get a 14-year-old boy on the bed and say we just need you to take all your clothes off. So that’s just not going to happen. So it is definitely, I think, especially with the pediatric patients, a real key issue that needs thinking about. We didn’t really have any major translation and rotational issues, though. So you can see the middle image at the top there is just very slight curve on the spine; it’s not dramatic, it didn’t cause problems with our treatment but we can all see now why that’s happened. We didn’t have an ROI in that area. You can also see that when we set up the patient, because we were using tattoos and isocenter moves, the delta for the vert was reading at a centimeter and we were like why is it reading at a centimeter?

Samantha Stevens (14:10):

This is bizarre but if you look at the bottom right-hand image there, he has so much gas, he was bulking up for treatment. He told us he was bulking up for treatment because he thought he was going to feel sick and lose loads of weight. So actually that’s why we had the big height move he’d put on weight and he had a lot of gas. This was consistent for the second day as well. So we just did a this in future reference capture, which resolved that issue. But otherwise AlignRT and our co CT matched really well.

Samantha Stevens (14:38):

So just a little bit about the learning that we’ve done about our ROIs. So this is Sam as a super user. It’s been great to get trained by her and have like a small cohort of staff that are trained to do these just for consistency. This was the first patient that we tried so we were avoiding her right-hand side because she’s got a line and wiggly bags which for pediatrics can be really tricky to avoid. And we did have quite a few issues with her images. You can see we’ve probably gone a little bit too far just across her ribs. Probably getting a little bit of breathing and motion in there. So when we treated a similar area, we moved on to something a little bit different. So we still went quite thick across the top. But we brought it a little bit lower across her pelvis just to avoid that breathing motion over her hips for a bit more topography.

Samantha Stevens (15:19):

And then, as you saw before from one of our case studies, we’ve now learned that a tear across the top can really help with the O that we’ve been struggling with. So we’re going to try and go ahead with something like this in future. And then for the brain, so with the open face masks, I think with this one, again one of our earlier patients we went quite low down on the cheeks and when they’re really struggling with contour change from steroid use that is causing us some issues with pitch. So we’ve moved on to something like this. We brought it up ever so slightly on the cheeks, and also with our masks we’ve got quite a limited field of view. So I’ve seen some of the vendors that have got more open sides, particularly for the pitch. So we’ve had to bring that down a little bit on the forehead. So again, it’s just learning points for us in the future of our equipment. So

Molly Bamber (15:59):

Our impact so far is very difficult for us to compare pre SGRT with post SGRT. The patients pre SGRT weren’t have daily imaging. So we can never make a direct comparison. However we are already seeing a significant decrease in the number of repeat imaging. So pre-AlignRT, 14% of our brain patients had repeat imaging throughout their course of treatment. That is down to only 2% of treatment fractions now that have had repeat imaging, which I think we’ll all agree is actually quite significant. Patients, therefore on the treatment couch for a shorter amount of time, which is ultimately Molly’s aim, has been is to reduce the trauma for these patients So the less time that they’re in the hospital. If we can remove LMA for nasal cannula, if we can reduce the number of times we have to re-image, it’s far less stressful for the patient, it’s less invasive for the patient. And it’s far less stressful for the families

Samantha Stevens (16:55):

Just to add as well. It probably can reduce the amount of GA that we would need to use with vaping face masks, the children will be much more comfortable. So I think it’ll make a big difference to them too. So yeah, our next steps, we’ve got grand plans but I think in the shorter term, we are just looking at trying to go tattoo list. It’s trying to get our clinicians a bit more on board and the confidence of our staff members, just to feel comfortable with that. A potential idea is having Tegaderm just as a backup whilst we’re still only got the two machines with AlignRT on. But I think something like even just doing this presentation with our colleagues will help just to give them the evidence of the difference that we’re already making and probably get some feedback from the patients as well just to see how they feel in their masks and how much shorter the timeframe might be that they’re on the bed.

Samantha Stevens (17:37):

At the moment, it’s anecdotal; we’re telling you that it’s shorter and it should be better for the patients but we need to provide evidence for that. So hopefully do a time audit and also do an immobilization audit alongside that, just to see how much more open we can get these face masks. Also, we would look to apply our learning to the adult cohort, so when we have another machine with SGRT capabilities, it’ll be looking at whether adults, obviously, based on the evidence today, have been pretty helpful. Whether adults can wear open-face masks. And then, as Sam was saying before, particularly for our cranial patients but in general as well as working with Vision RT further to see how we can improve our ROIs in future for better patient treatment for the patient. It’s a little bit of just our acknowledgements

Molly Bamber (18:18):

We definitely want to acknowledge Johnny Ridge, who can’t be here today, and he should be here today but unfortunately can’t and he has done so much work with us, hasn’t he, on this project. So yeah. And definitely everyone at Birmingham who supports us and our lovely colleagues who are here to support us and Vision RT as well, because you have been a great help. Thank you very much, everybody.