Clinical Application of Open-Face Masks Combined with Surface Guidance in Head & Neck Stereotactic Radiotherapy

Dawid Bodusz (00:04):

So good morning, ladies and gentlemen, or hello everyone. It’s a great honour and pleasure for me to be here and to be with you after this amazing evening as well. And I would like to take you on a little journey through our experience. You can see on this slide open face masks and surface-gated radiation therapies. So, AlignRT is used in patients undergoing stereotactic radiotherapy for head and neck regions. As we all know, probably all and probably know in contemporary radiotherapy, especially in stereotactic radiotherapy, we live in the world of strict precision. So we live in a world with millimeters and degrees, and sometimes it looks like we talk about our patients, about problems, about our setup accuracy every time. And do not speak about, for example, holiday plans.

Dawid Bodusz (01:14):

But I hope it’s not true. So today I want to show you how we in our department try to keep our submillimetric precision under control, and at the same time keep our patients a little bit more comfortable and a little bit less claustrophobic. So to do that, I need a plan. I hope I have it today for this presentation. So I will try to introduce my own radiotherapy department, explain how and why we moved towards open face mask and surface guided radiation therapy. Show you some data about setup accuracy, infractional motion few words about bite blocks influence of bite blocks on this accuracy. And finally, I will try to translate all information into clinical conclusions. So let me start with a little bit of context, where all things are happening.

Dawid Bodusz (02:28):

So here you can see my radiotherapy department and part of my hospital. It’s a comprehensive cancer centre, and you should know that we have separate radiotherapy departments, separate BRCA therapy department, and separate treatment planning department. It’s not standard even in Poland, but we have separate this ra treatment planning department as well. As you can see, we are quite a busy department radiotherapy department, because at this moment we have 11 linear accelerators. Eight of them are C series of standard Linacs, seven TrueBeam, one Edge, and six of them have AlignRT systems, two of them do not. Maybe in the near future, I hope that in the next year, we can buy a new treatment machine. So we treat we buy it with AlignRT, of course, because it’s a standard for us.

Dawid Bodusz (03:34):

So we have KV imaging one. So it’s a CyberKnife with MultiLeaf Collimator and one, it does some solution for native radiotherapy. We started a native radiotherapy last year in April 2024, not two, but free operative units. We have actually, at the moment, one superficial hyperthermia unit. In the near future, we want to buy a deep hyperthermia with MRI, I hope it will be with MRI, to check the temperature inside the patient as well. So per year in total, we treat about seven thousand patients. And daily, it’s about 300 free 15, 315 sometimes. And with such a workload, if we change something in our procedures like immobilization systems, like imaging procedures, it cannot be only beautiful on paper, but it has to work on a scale. So it should be safe, it should be reputable, and it cannot destroy our daily schedule.

Dawid Bodusz (04:57):

So if we talk about open face mask and we talk about SGRT, we do not talk about a few or several patients per year, but we talk about workflow. It must fit into the large real-life department. And of course, these all things are managed by multi-disciplinary teams. As you can see, we have a lot of RTTs in our treatment machines. 34 radiation on cardiologist, six nurses. And you can see here on the slide radiation physics medical physicists, but they exist, but in a different department, of course. So treatment planning department and a special department for QA and measurements. Okay. This is a slide about our environment because we try to have a quite nice and friendly environment for our patients and our staff. So we try to have some wallpaper, some nice slings, and you can see here our auto therapy unit with modern lines.

Dawid Bodusz (06:08):

So if we have a lot of problems, a lot of patients, and we need to take a deep breath, for example, we can go to the tunnel therapy turn, switch on the lights, and have fun. Of course you can, you can we, we have here the video without sounds. Okay. So how can even consider changing our standard approach because it worked. So, there are two simple reasons. First, it was that we implemented it into our clinical practice edge. So it was our first machine with align RT system. And with this machine and with this system, we took a new immobilization system for stereotactic. Radiotherapy Edge is a machine dedicated especially to radiosurgery or stereotactic radiotherapy. And the second full face thermoplastic masks are a very good tool to manage the motion, but have some jaw backs, for example, limited visibility of the patients.

Dawid Bodusz (07:26):

And for example, sometimes more anxiety and reduce camera based monitoring. So we can use SGRT, of course. So that’s why we started with open face mask, and we had free objectives to this study. Why? Because we tried to answer the questions, can we be as accurate as in the standard procedure with a face mask or even better, and at the same time, make our treatment more comfortable, so patients are friendly. So we had three main objectives. First, to evaluate positioning precision with an open face mask and SGRT. The second assess the patient’s ability during treatment, values vary and to determine the optimal routine. And because we all like some details, we checked the influence of bite blocks in our patients as well. And it was very important for us because new immobilization system we use, has the possibility to use two different kinds of thermoplastic masks.

Dawid Bodusz (08:44):

I will show you it a little bit later. So we included three groups of patients. The first group, it was Qfix group, so it was an original kind of open face mask for this system. We use it on 51 patients with Qfix open face mask, 100 patients with a Klarity open face mask. It’s compatible with our IM immobilization system. Additionally, we have something like a control group, because it was 42 patients with a closed face or fit mask, but treated in a standard fractionation. So standard radiotherapy. We had about 100 for 1,400 measurements. So what about our treatment, daily treatment machine workload for this group of patients treated with stereotactic radiotherapy, we set up the patients using, of course SGRT system. So we had not we have not here any markers on the face mask.

Dawid Bodusz (10:01):

We just used the SGRT. So the next step was CBCT verification to get some information about our accuracy and inaccuracy, of course, to verify the position to move the table to the correct position and to assess the accuracy of our systems. And the last step was treatment delivery, of course, with monitoring SGRT monitoring during the one session of radiotherapy. We had 200 measurements for Qfix group of patients about 400 measurements for Klarity patients, and about 700 measurements for Orfit. So full phase mask radiotherapy. Here you have information, same eye as I told you. And here you can see our immobilization system. We use it for this group of patients. So for Qfix and Klarity, what is very important that for this encompass, SRS imobilization system, we can use an original open face mask, but we can use a Klarity mask as well.

Dawid Bodusz (11:22):

Both of them are compatible with this system. Of course, you can see that this symbolization system provides rigid fixation to minimize movement in all three special dimensions, and so on and so on. Here you can see the original open face mask with bite blocks. It looks like this one. Here you can see the clarity mask with some differences. So it’s similar, but for example, bite blocks look like a different fig in this way. Of course, we did some statistical analysis, descriptive statistics on non-parametric methods due to the fact that most variables deviate from distribution. And here you can see our results for this system. So, first of all, it’s not surprising that Orfit systems or standard fractionation, standard full face mask show us that results are larger than for the SRS system.

Dawid Bodusz (12:32):

So both systems Qfix and Klarity. And these differences are for all translations and all rotations, excluding vertical. Because vertically, we saw that there are a little bit better results for Orfit. So, for full face mask, we do not know why. What’s the reason? But probably we found the last few months that we had some problems with. We’ve outlined our skin and our body. There are some differences between skin and body, and we, if we use some of them, we can see some oh 0.5 millimeters differences between our results in SGRT system if we check Qfix and Klarity, which is very important for us? Can we use Qfix or Klarity or not? We do not see any big difference. And what is very important, our inaccuracy is less than three millimetres, even in vertical translation, and for longitudinal and lateral translation was about zero millimetres.

Dawid Bodusz (13:56):

So we are very, very precise in these translations and for rotation, all are below one degree. So it looks like we are quite precise. There are some statistical differences between system, between Orfit of course, and Qfix and clarity system. It’s not surprising. And if we compare both group of system for full face mask, we see the lower vertical translation, but it’s not bigger than oh 0.5 millimeter larger longitudinal translation, greater rotational division and higher jaw dispersion for Qfix and Klarity. So both together, higher vertical translation, but smaller longitudinal translation, lesser rotational deviation and lower jaw dispersion. And there are no significant differences between QFI and clarity in the vertical or lateral axis. What is very important for us is a few words about the influence of bite blocks. Well, if we use it for a subgroup for Qfix system and for Klarity system, there is no measurable impact on translational accuracy across all access for both systems, for Qfix and clarity.

Dawid Bodusz (15:30):

But we found some significant improvement in the jaw if we think about Qfix system and some reduction in pitch error in Klarity system. So here you can see the same results in some images. And you can see that if we think about translational, there are no differences between bite blocks and with group without bite blocks and some differences if we think about cfi system, we found some differences in rotation and for clarity in a pitch, as you can see here. So what about intra-fraction motion? Because it’s very important to have an open face mask. Are we precise and are our, and are our patients stable during the one session of treatment or not? As you can see, we saw that it’s very good results because it’s less than one millimeter, even five oh 0.5 millimeters.

Dawid Bodusz (16:49):

So we saw that it could be a safe solution for this group of patients. So to briefly summarise the translation precision median residual translation was less than three millimeter for an open face mask, even less if we talk about longitudinal or lateral direction. And rotations were less than one degree, consistently outperforming closed face masks. So it looks better, what about the time which is needed to set up the patient in this project? Unfortunately, we didn’t collect any data about that one, but we had a presentation at this time. And it’s similar, and the results are similar to our experiences that we do not need more time to set up the patients if we have a well-trained staff. So, RTTs working on the machine, our results are similar to the other publications.

Dawid Bodusz (18:02):

It looks like these systems are safe and producible. So we can conclude that open face masks combined with SGRT clinically superior setup precision can safely replace conventional laser guides, closed mask positioning, Qfix and Klarity mask are functionally and can be interchangeable in clinical practice. Bite block selectively enhance rotational control. So pitch or rotation and routine use should be reserved for critical cases requiring sub-degree rotational margins and open phase surface guided radiation therapy workflows, reducing the need for skin tattoos and minimize additional imaging exposure. And last, maybe in the slide, it’s especially for our Vision RT team. So what does it mean AlignRT? It means accuracy, less setup time, improved patient comfort and precision, no additional imaging dose, real-time safety, and trusted technology. Thank you very much.