SGRT Forum

We have one patient we are treating that is a DIBH with bolus (3mm). The issue that we are facing is that once we recapture, with the patient in breath hold, the deltas are still in tolerance once she is told to breath. When we set up to free breathing and then switch to BH she is clearly out of tolerance (not teetering in and out) so we're unsure why this is happening.  We've changed her tolerance to 2mm instead of 3mm and this has helped. Wondering if anyone has had a similar issue and what your solution is.

Thanks!

Hi Jen

To me this seems like patient can not relax her chest wall after BH. This has been noticed to be a common case already with RPM (where baseline may sneak nearer the BH window when the amount of breath holds increases during the  treatment, n+ and ablation). With SGRT we see this much better (more deltas visible than only vertical).  Some patients may leave their chest wall to tensed position (residual air or patient position has changed) already after one or two BH:s (which seems to be the fact in your case) but usually they get tired after several BH:s. We have noticed that patient guidance to relax their chest wall to setup position is very important in several points of entire workflow to avoid the errors in the images.  I think bolus has nothing to do with this, difficult to say exactly.

Marko

I'd like to know how many people are treating DIBH with bolus, if they are 2 field, 3, or 4, and how things are going. What type of bolus are you using? Do you find it conforms well? How much time do you give to treat these patients? We are finding it very difficult to treat DIBHs using VisionRT. Our biggest issue seems to be that once we've set up  and started treating, the patient comes out of tolerance and we have to go back in several times to remove the bolus and and take a new reference capture. Right now our tolerances are set at .3cm. Do most people open their tolerances? Any info you can provide  is extremely appreciated!

Hi Jen,

We are just starting to use bolus with AlignRT, and don't have too much to share yet in the way of clinical experience, but would be interested to know which bolus you're using?

From our initial trials AlignRT seems to be able to pick up the surface of white coloured Bart's bolus  without too much trouble. When we tried with superflab, however, the surface wasn't great, with lots of holes appearing (we think possibly because the bolus is partly translucent).

Cheers

Hi Jen,

We treat our chest wall patients with bolus at QEHB in Birmingham, UK.  We leave the tolerance at 0.3cm and we don't struggle any more than normal DIBH without bolus.  We use 1.0cm think bolus slabs and we treat 2 or 3 field patients in this manner.  If the bolus doesn't conform well (breast re-con) we ask our mould room technicians to make us a custom gauze type bolus which is more flexible and sits on the skin surface better.

The only time we really struggle is for patients who struggled with BH for the first 8# anyway - then when we move to last 7# bolus, they continue to struggle and we end up replacing bolus and re-capturing etc. rather than managing with the original re-capture at the beginning of the session.  We have never had problems because of the bolus i.e. if the patient coped well prior to bolus, we don't see them struggle with bolus in place.

We do have to cover the bolus completely in paper as the reflection it shines back from the camera flash interferes with the surface capture.  This makes the deltas more reliable and less jumpy as if the surface capture has 'holes' there is less for the system to monitor.

Hi,
We use aquaplast sheets for our bolus.  They are custom formed for each patient during the sim.  They mold well, have very little air gap, and I think because they are white, we have never had a problem with it going out of tolerance once it is in.  Our bolus is 0.5cm and tolerance is 3mm.  I had never thought about it before since we used this bolus before we had VisionRT, so I don't have a comparison.

Beth

Beth,

We're currently looking into ordering the aquaplast to try it. If you would be willing to share your technique in using it as bolus, i.e: is it created in sim? are you using bolus every other day for your treatments? I'd appreciate the opportunity to keep in touch with you as we become more familiar with using it.

My email is Jennifer.rios@rwjbh.org

Thanks!
Jen

For anyone using aquaplast as bolus for DIBH's. We're looking into it as an option and have a few questions. What size are you using? What are you using to heat it? What thickness and is it every day every other? Do you find that the final thickness of the aquaplast is consistent after conforming it to the patient , or does the thickness very without? Are you still just doing 2 scans in sim: 1 FB and 1 BH with the aquaplast already on? Any information is greatly appreciated as this has been an issue with us for quite some time.

Thanks!

Jen

For anyone using aquaplast as bolus for DIBH’s. We’re looking into it as an option and have a few questions. What size are you using? What are you using to heat it? What thickness and is it every day every other? Do you find that the final thickness of the aquaplast is consistent after conforming it to the patient , or does the thickness very without? Are you still just doing 2 scans in sim: 1 FB and 1 BH with the aquaplast already on? For cases where the supraclav is also being treated, do you remove the aquaplast when treating that area? And if so does it change the patient's surface in a way that might affect the way AlignRT picks it up since the plan was made off of the scan with aquaplast on? Any information is greatly appreciated as this has been an issue with us for quite some time.

Thanks!

Jen