Surface-Guided Radiation Therapy with TrueBeams

I have about 20 years of experience in radiation therapy. Like she said, I’m currently the supervisor at our Wesley Chapel campus, and we got introduced to SGRT about five years ago. So today I’m just going to be giving an overview from a therapist’s view of what our daily treatment setups, ROIs, and how we utilize AlignRT in our campus with the TrueBeams.

For treatment machines, we do our daily warm-ups with our vision plates just for accuracy within our two-millimeter tolerances for patient setup and monitoring. But everything pretty much starts with CT simulation. We don’t have MAPRT or Dose RT. I’m really going to be pushing for our center to get that because it looks all amazing. But this is always the first step to SGRT for us to be successful for alignment during treatment with patients.

For our patients, they are uncovered for the full length of their scanning range. We cover their genitalia if it’s included for the scan range. We always make sure that the scanning range extends beyond our immediate treatment volumes to just make sure there’s adequate skin surface that we can use that’s reliable for setup and verification using our cameras. The only exceptions is where immobilization masks are used.

For brain and head and neck setups, we use three different open-face masks. We have the SRS mask, a short S frame, and a long S frame. All of these are made with an emphasis of the sides going to the interior of the edge of the patient’s ears. The superiors stretch to basically their hairline, and the inferior stretch below the patient’s mouth. And this is an example of our open-faced SRS mask that we use. Once it’s completely cured, we always just make sure, like I said, when you place that top, you can see how far down we go to the edges of the ears, top of the hairline, just to ensure that we have enough surface for our cameras to use for treatment. And we always fold the back portion across just to make sure that it’s tightened around the back of their head and that we continuously lift around their neck so it doesn’t tighten around their airway there.

This is an example of our ROI that we use when we draw them. The patients, we do ask them also to close their eyes, but you can just visualize the area, and we just make sure we don’t include the mask when we’re drawing it. This is an example of a patient setup in our treatment room with it. Surface guidance is dependent on our defined ROI since it displays and tracks only the surface data captured by the camera in that region. So once everything is green, we know that we’re good for alignment and ready to proceed with imaging. Same parameters apply for our patients in our long open S frame masks. The only difference here is that we include that neck region to provide more surface for treatment. And here’s an example of a patient in that type of device.

For our lung, breast, chest walls, T/L spines, and ribs, all of our patients are in a wing board with either a custom back lock or a short or long body fix. We mold it around them to make sure that we leave enough lateral skin surface for the cameras to detect. After the iso is set in SIM, we shift the lasers into position, and we only put lateral marks on the cradle, and then we just take pictures of where the laser visually falls on the patient to use for setup.

There are definitely multiple ways to draw your ROIs, as it’s been discussed, which is very important for treatment. This is the most common one that we use in our practice that we have found that is the most efficient. We always exclude our axilla just because if your shoulder position is different, it’s just a concave area that we just exclude. Here is an example of a few different other ROIs that can be utilized. We always aim to exclude our diaphragm whenever possible since it’s a significant area for motion that would impact how your surface guidance accuracy is for setup. To mitigate this, we found that shaping the inferior border of the ROI into kind of a mountain peak configuration can help alleviate that. Even if we have cases where your ROI is located lower or near the diaphragm, we still avoid placing your ROI there. It doesn’t have to be exactly over where you’re treating for it to be effective for treatment and tracking. This is another example for an SBRT lung that we use. We, again, utilize that mountain peak shape with the inferior border of the ROI, particularly beneficial for beam control patients since it minimizes that impact of the diaphragmatic motion on surface tracking. If significant motion persists on these types of patients, then that’s when we would utilize our gated reference.

We love SGRT specifically for SIM from plan patients. Here you can see our original iso is in the red circle, and our SIM from plan is in the green. It definitely allows our therapist just to be able to directly go to that new iso, visualize it on the patient in real time, and verify accurate setup in the treatment room. Not all of our campuses have VisionRT yet, so you’ll see through some of these examples that these patients do have tattoos still. We do not utilize them. And you can just see when further in our slides here that they are used for leveling at other centers, but with Align SGRT, it doesn’t have to be exact. We stick with Align and Vision, and that’s what gets us to our treatment positions.

Here’s an example of our ROIs that we utilize for our breast or chest wall patients. This patient is a post-mastectomy case. You could wrap the ROI inferiorly under the patient’s contralateral treatment side. This can optimize your camera visibility for both setup and treatment. This is just an example of an intact breast using the rectangle shape. This is what we found more recently. It really utilizes any kind of interruption with camera blockage for patients when the gantry is rotating. So this has been our most beneficial, just wrapping it all the way around using that rectangle shape for treatment for breasts.

For prone breasts, we use the CVR Prone Breast Board. Doctor still comes in, places the wires on the breast. We position the patient onto this board, and then we fill this form out, which gets then uploaded into the patient’s treatment chart. It also includes where the laser falls on the patient’s breast, whether that’s mid-breast, nipple, superior of the areola, or wherever it lands. In addition to measurements that we take superiorly, inferiorly, and medially to where the breast is in position to the breast board. And here’s an example of a patient on and off of that board. These patients, our therapists still like them to be tattooed, just because we get significantly a lot of prone breasts in all different shapes and sizes. And have just found that even though we use a line for our setup with the tattoos after—I’m sorry, we use a line after we do our initial tattoo setup. We then use a line to do our shift to our actual treatment position for setup. And just because breast tissues are very pendulous and they can move, we just still like to have our tattoos to help us guide us in positioning if there’s a struggle.

This is an example of the ROIs that we use for our prone breast patients. This is for a left breast. It shows your grid view that you can also view. It’s a rectangle shape that’s drawn across the back, and then it’s wrapped around the side of the left breast. On that bottom right image, you can see the PA region, which intentionally is partially excluded from your ROI. If you try to include that breast part for your ROI, then that area would cause the system to try to look at that area, and obviously, it would be blocked from the table. So it’s just important to note that when you’re drawing your ROIs.

This is a picture of a patient in that prone position for treatment. The top row shows our initial setup; we’re utilizing those tattoos. And then the bottom shows when we shifted using SGRT. You can see that it’s not perfect on our tattoos, but again, we don’t rely on those anymore, so we proceeded. So in the top row there, you can see our pitch we struggled with a little bit. We didn’t manually adjust for it; all the parameters were within, so instead, we utilized our Send to Couch feature. We shifted the patient into the treatment position, which resulted in everything being green and very minimal. And then we were able to continue for our CBCT. Sorry, I wanted to note one more thing on this. After we captured our reference, you can see on the bottom there, there’s a black gap on the side, and that’s due to camera blockage, but it doesn’t interfere with any kind of treatment. We still have enough surface that we provide for it that you’re able to proceed without any issues. It’s just because of how high they are on the table.

These are examples of the ROI we use for our pelvis patients. We place either cloth or a folded pillowcase over the genitalia to just make sure when they draw their ROIs that it’s not included. This is an image of that being utilized for a patient with our Sifco knee cushion. And we do the same for if they’re in a custom foot cradle. And it’s the same for our prone pelvises that are on the prone belly board. And that’s an image of the patient on the table utilizing that setup.

So we are the only campus currently at Moffitt that utilizes this kind of setup for our CSI patients. We are still trying to actively educate our physicians on its success for potential future implementation at our other sites. We have found that by using this setup, it has gotten our treatment times down to about 30 minutes as opposed to an hour plus. We use a long BodyFix index with a U-frame holder, a short closed mask with an extended neck. Their arms are down at their sides with their palms against their thighs with no footwear. And at CT, we set a depth midplane for the brain, and then we take a measurement down about 16 to 18 centimeters, and then that’s where we will mark the patient for that first iso, which is around C1 level. The AP left and right are marked and BB’d. Dosimetry will use those coordinates and that iso to then give us our upper and lower spine isos. We keep the same depth from the brain iso, and then we just place inferior marks. And these patients, we still do tattoo as well, just because we’ve only seen a handful of them and have done them this way. And then we put as many marks as we can for reproducibility. We put them at the top of the shoulders, thumb creases, tips of the middle fingers. They can be different on each side depending on where their hand placements are. And then we take photos of everything. And this shows you the image, the top of the mask, and then all of those marks that we put along the sides for the patient position.

For our extremities, we make custom back locks for them. We always make sure that there’s enough lateral side views so that Vision can see their surface. Again, once the iso is set, we just take pictures of where the lasers fall and any additional setup photos. This is an ROI drawn for a knee, just making sure on that lateral side that the cushion is not included.

On to setup in the treatment room. We didn’t utilize tattoos. This patient wasn’t sent to our campus, but came to us with tattoos. But again, we just ignored those. And you can see that they’re not exactly lined, but again, he imaged greatly and set up very well.

So an overview for our patient setups with alignment in the treatment room. For mask, we use AlignRT to adjust the patient prior to placing the mask on the patient, and then we place the mask to make our final adjustments, which really helps reduce your pitch, yaw, and roll. If they’re in a cradle or body fix, you align to their level marks on the cradles, and then we adjust the patient superiorly and inferiorly with Align to help with any pitch issues. And then we continue with Align for remaining adjustments. If they don’t have any immobilization devices, we just visually make sure our patient is straight with our lasers and that they’re not rolled, and then we just adjust the patient, also utilizing AlignRT.

So we’re going to go through an example of our brain XRT. We start all of our setups with the postural views with the cameras, video tabs, toggling between those three views. We adjust the patient’s head roll and pitch to make sure they’re all less within two millimeters, and then we place the mask on. We utilize our Send to Couch feature with our 3D Off being selected. We don’t do any more than the 3D Off just because if you had any additional, for some reason, higher shifts, you wouldn’t be able to apply them.

And another great feature that we love is our SSDs. As long as your gantry’s at 0 or 180.1 and there’s no camera blockage, Align will give you your SSDs. If your gantry is blocking, you will see that it’ll show fail on the current versus what your planned target is. After imaging and application of shifts, we always make sure your gantry is at that 0 or 180.1 if you’re not already there to avoid your camera blockage, and that’s where you reference your capture for the session only. If we had shifts that were greater than five millimeters, we will select this in future sessions. That prompts AlignRT to utilize that reference for the setup alignment and all your subsequent treatments for the patient.

Once your reference is captured, all the positions should be within your tolerance and the patient’s ready to proceed with treatment. During treatment, if the movement exceeds the set site tolerances, the parameters will turn red. That’s either due to camera blockage or actual patient movement. To assess that, you’re going to observe your ROI, and if portions of the green are gray, then that is 99% of the time camera blockage, but you want to verify that by, again, moving your gantry to 0 or 180 or 180.1 to make sure it’s camera blockage versus actual patient movement.

This is an example of a C-spine treatment. Again, they were aligned. They had a long open-face mask. We did our minor adjustments, proceeded to imaging. After we did our shifts, we captured the reference. We did draw ROI on that lower portion. Not necessary, but again, the more surface you have provides better aid and just surface setup for your patient.

This is an example of an SBRT lung treatment. During the initial patient setup in the treatment room, our parameters were slightly over three millimeters, but we still utilized our Send to Couch feature and 3D Off, excuse me, to the correct positioning. Once it brought it all into the parameters within tolerance, we were ready to start imaging. After shifts were applied, our tolerances were flashing in the red, so we knew that this was indicating there was a respiratory motion. So to help minimize interruptions in the treatment, we utilized our gated reference capture. By selecting this, you get this gated graph that appears, and it displays the average baseline from your patient’s breathing pattern. The therapist will select your average of the pattern and select Accept. This is going to help reduce unnecessary treatment interruptions while maintaining accuracy. If irregular breathing continues, then the therapist will help instruct and coach your patient to try to just take normal breaths and not keep going in and out of range. Sometimes we have to do this a couple of times if the patient is just struggling or having sporadic breaths, so you can do this a couple times and just make sure you’re getting that average of your graph there.

All of our SBRT CIBHs, which is a comfortable versus a deep breath hold, DIBH, SRS, FSRTs, and our CSIs are all beam controlled. So if that patient moves out of that preset tolerance, they’ll turn red, and they will shut the beam off. If tolerances are consistently fluctuating between our red and green, which sometimes happens but not a lot, we will adjust our ROI to exclude areas that is causing the most motion. In this case, the ROI was modified from that mountain peak kind of rectangle shape, more to a square shape to reduce lung inclusion and to limit the tracked surface area. Here, there’s just minimal motion. All parameters are named within tolerance. You can go ahead and play it. And this just shows while the gantry’s rotating, you can start seeing that gray area. That’s where the camera’s blocking it, but you can still see it has enough surface, and it’s not interrupting that patient’s treatment anymore.

Another added benefit that we like about SGRT is our ability to adjust for variations for skin tone. If Align’s having difficulty seeing either darker or fairer skin tones, you can adjust from fair to dark to enable better detection from your cameras to see your patient’s skin surface.

To conclude, AlignRT does have a few things that we noticed that were some disadvantages. But just like everything else in the world, nothing is perfect. And with that being said, we would strongly prefer to continue utilizing this than have it taken from us, because we love it. So some of those disadvantages, like we discussed, sometimes your camera can cause a pause in treatment if it’s blocking too much and you have to stop and edit your ROI. Sometimes, we’ve noticed more so with extremities, for legs, when you go to capture your ROI, it may capture a different surface on your other leg. So you just have to stop and re-edit your ROI and re-reference it. We have had some technical problems that makes you start because everything has to open up properly to restart all your programs. And just on occasion, patient setup has been green and looked great, and then we’ve gone to image and has been off several centimeters. And this is why our doctors still want us to still image, just because this is more so in a case of like a spine, and that’s just because sometimes it just can’t reference when you’re doing a rectangle, where exactly it’s seeing on that patient. It doesn’t have enough information.

In contrast to those, they have numerous advantages. It improves patient comfort by eliminating the need for tattoos and restrictive masks. It enhances safety and efficiency through real-time surface tracking during treatment delivery. It identifies setup variables prior to imaging. For example, arm positioning, head, chin, tilts, and rotations that are especially important for our breast setups. It streamlines patient setups and positioning, reducing overall time on the treatment table. As I said, in our CSI cases especially. It improves respiratory management for our DIBH gating treatments with visual monitoring of breath hold and breathing patterns. It also eliminates variability from daily placement of external marker boxes on these patients and trying to replicate that every day. It increases our therapist’s confidence by providing continuous motion monitoring rather than relying on assumptions during treatment. For example, if they coughed or sneezed in the middle, if they actually moved, or if they are still good in their position to continue with treatment. It also enables automatic surface guidance and from plan shifts, as I showed earlier. It supports accurate bolus placement verification, and it’s applicable across a wide range of treatment sites. And that’s the end.