All right, so I just want to thank you for the opportunity of me being able to present my experience, Lessons in Ultrasound Guidance at Peter MacCallum Cancer Centre. My name is Ryan Urban. I'm one of the radiation oncologists at BC Cancer here in Vancouver, Canada. And unfortunately, I couldn't join the live webinar due to the time zone differences, but hopefully this recording will add to the conversation today. So just an overview of my time, fellowship experience at Peter MacCallum Cancer Centre. I was there in 2022 and mainly focused on gynae and GU brachytherapy. Nothing but great things to say about Peter MacCallum, the entire team there and the learning experience that they provide and the care that they provide to their patients. These are a few of the snapshots. I was able to participate in a few demos with phantoms. This is an HDR prostate type of example, but we did some demos with gynaecological brachytherapy and it's really just a beautiful building and such a cutting edge centre in the world and a real privilege to be able to gain some experience there. Most of my time in gynae brachy involved using the Electa Geneva applicator depicted here. And this is a combined intracavitary interstitial applicator. You can see two ovoids and a tandem and then these ovoids have these small channels, which allows you to use the interstitial capability if you choose to use or if you need to do that for your particular patient. And then here's the rectal paddle behind it. So Peter MacCallum is a high volume centre and we did a variety of cases during my time where both just standard intracavitary where there's no needles required and here's the applicator all set up within the operating room. And then also for more complicated tumours, either because of the size or the symmetry of it or the asymmetry of it, using more interstitial capability to better cover the tumour and improve your dosimetry. Which I'm sure you'll learn a lot more about during this webinar is the way ultrasound is used for the brachytherapy practice at Peter MacCallum. So they use a variety of transabdominal, transrectal, transvaginal ultrasounds to not only plan for the brachytherapy, but then also facilitate the brachytherapy during the procedure, verify the positioning, which just gives you so much more confidence during the procedure. It's much safer and allows you to have more effective brachytherapy implants. This is a particular example of a transabdominal axial view of a patient with a cervical tumour and we're using interstitial capabilities on her right to deposit these needles. You can see the ureter with a stent here, just shows you how crisp the images can be. If your ultrasound program is set up, it just, again, gives you so much more confidence while you're in there. You're doing the right thing. You know where these needles are going. So when I came back to BC Cancer after my time at Peter MacCallum, we previously had used a variant system, which included mostly a tandem and ring, and we completely converted over to Elekta in the winter of 2023. So we've been using it for roughly a year and a half now, the Elekta-based system. Mostly we've used the Geneva and multi-channel cylinder. We did purchase the Venetia and we're commissioning that, but we haven't had an opportunity to use that. I know when I was in Australia at Peter Mac, they also had the Venetia, but I don't believe it was commissioned yet. I'm curious if that has been done since I've left, but essentially this one has these semi-lunar rings, sort of like a semi-lunar ring ovoid with the interstitial capability that are not only parallel to the tandem, but there are some oblique channels. And then there's this perineal template, which allows you to do some more perineal interstitial needles if needed. One of the things that we've adopted based on the experience of Peter Mac is using more ultrasound modalities and different ways of using the ultrasound. One of the ones is the transrectal ultrasound approach, and this is helpful. For me, I do a lot of prostate brachytherapy as well, so I'm used to doing transrectal ultrasound in patients with prostate cancer, and we're trying to adopt that into the gynecological world as well. This is just an example of what that could look like. This is an example of a 72-year-old female with a previous history of hysterectomy in 2012 for an early stage endometrial cancer, and then unfortunately had a right supravaginal recurrence as depicted on this MRI. And she was planned for radiation with brachytherapy, and this is her brachytherapy implant. We use some interstitial needles to cage the tumor, as you can see on the axial views, these interstitial needles. We used that transrectal ultrasound, and it was quite helpful. That's a skill that our team is continuously trying to build with the experience from Peter Mack and how they've used it routinely. Some of the challenges that we've had here, so at Peter Mack, we did a lot more complicated perineal templates, and a lot of the cases that required that from surrounding hospitals in the area around Peter Mack, they would get referred to Peter Mack for some of these implants. This is a particular example of a patient with a SIAD template, a variety of interstitial needles, and actually some freehand needles through the vulva. Not infrequently for some of these implants, we would actually have the assistance from gynecology of doing a laparoscopy to see where some of these needles are going in to make sure we're not perforating bowel or adjacent structures, or even sometimes putting a layer of omentum in this area to just give us a little bit more room for the dosimetry in some of these cases. Unfortunately, at BC Cancer, we don't have the inpatient resources right now to effectively support these complicated implants over several days, and we don't unfortunately have the gynecology support to do some of these laparoscopic-assisted brachytherapy procedures. One of our provincial institutions has a particular interest in the perineal templates, and it is an option. However, it's about a four or five-hour drive away, and patients for a variety of reasons, family reasons, or just being close to their loved ones sometimes don't really want to travel, and therefore, we have to come up with some new approaches. What are the things that we have done to kind of mitigate some of those things? Some of these cases that I'll present will kind of highlight that. The first case is a 52-year-old female. She had a subtotal hysterectomy in 2007 for fibroids at the time of a C-section. She then presented with some post-coital bleeding and was ultimately diagnosed with an invasive adenocarcinoma of her cervical stump. An MRI in PET showed a relatively small primary, about up to two centimeters, with some possible perimetral invasion, and her PET unfortunately showed some retroperitoneal lymphopathy, and she was planned for chemo-radiation with a brachytherapy boost. This is her MRI sagittal at time of diagnosis. You could see the cervical stump. There's no more uterus here. She has a small primary, but because she had a cervical stump and some lymph nodes, she was planned for chemo-radiation with brachytherapy. Now here we give five weeks of radiation with the chemotherapy, and we often start brachytherapy depending on how many patients are currently getting scheduled for brachytherapy, but often during sometimes week five or sometimes just shortly after finishing external beam as the tumor shrinks. To prepare for that, we were anticipating this might be a little bit more challenging than a standard cervix brachytherapy implant. We obtained a pre-brachytherapy MRI, which is something that Peter Mack does not infrequently as well, just to give us some more confidence and plan for what we're going to do in the OR at the time of her first brachytherapy fraction. This is a fraction of 20 to 25, so roughly four weeks done of radiation. She had a good response. Her cervical lesion is now only measuring about a centimeter in size. What I did here was actually in the vault room where we do our adjuvant vaginal vault brachytherapy, so just a shielded room with no anesthesia, I did a pelvic exam, inserted the Electa ovoids based on her anatomy, and actually just put a blunt tandem in to see, and then obtained an MRI to see exactly where that Electa Geneva haplocator is sitting, and then give me an idea of whether I could put some needles in and how deep I could put them in. What I learned from this is you can see a nice cervical canal here, which unfortunately we don't have a tandem that's that small, but I had a blunt tandem in. I could possibly feed a blunt needle through the end of the blunt tandem and use that as a sound, and then I could measure how deep from one of the needle channels could I go with an interstitial needle to be safe and to avoid going in this region where there could be bowel that I don't want to perforate. That was the plan. I saw this small channel, I said, okay, maybe let's try a 1.5-centimeter blunt end needle from the blunt tandem and use that as a sound to sound this cervical stump, and then I could possibly put two needles in to roughly about 1.5 centimeters safely. At the time of her first brachytherapy fraction, that's what we did. This sort of diagram depicts that. We used the 25-millimeter ovoids in this case, the blunt tandem. Within that blunt tandem, I put the 15-millimeter blunt needle in, used that to sound, and you could see the transabdominal here, the bladder, Foley catheter, and then the remnant cervix. Right in the middle, you can see the blunt needle going in right in the center, and that actually went in quite easily under anesthesia. Then I used these two anterior medial needle channels to put those needles in about 15 millimeters as well. This is the transabdominal sagittal of me putting in the needles. On her post-procedure MRI, we get both an MRI for at least one or two fractions of the brachytherapy, and we also get a CT scan to help plan. This is her fraction one brachytherapy MRI. You can see the ovoids in, the rectal paddle in, packing, and then the blunt needle is sort of a little bit under some tension here, but within that cervical canal of the remnant cervix. The needles are a little bit more difficult to see on this sequence. On the coronal of the CT, you can see these interstitial needles. The one on her right didn't go as deep as I had hoped, but you can see depicted on here. Once we've contoured the high-risk CTV on the MRI, we convert that to our CT, and that's depicted here in this blue, so that's our target, and then the red is our 100% isodose. You can see that's covering the target well and just avoiding the draping sigmoid that's just above this cervical remnant. We continued with that for her three fractions, and we actually didn't need one of the needles for her remaining two fractions because we just didn't end up using it significantly during the first fraction. This is our dosimetry sheet, which we track every patient's external beam and brachytherapy doses. You can see her D90 that we achieved was quite high, 94.1, and I know my Australian colleagues probably think that's probably unnecessarily high, but nevertheless, her OAR doses, so both the bladder, rectum, sigmoid, bowel, all well below our hard constraints. Ideally, we'd get less than these, but all much below, and she tolerated this quite well and has had a great clinical response. The second case is somewhat similar. This particular patient was a 77-year-old female, so in her late 70s. She had a prior hysterectomy and vaginal excision in 2017 for H. cil. At the time, there was concern of invasive disease, but actually, on pathology, just H. cil was found. Then a few years later, she had acute cholecystitis, and at the time of imaging for that, had this incidental finding of this left supravaginal mass, which was worked up with MRI and PET, showing this mass and also a pelvic lymph node. On exam, her vaginal mucosa on that particular side appeared normal. You could only really feel this mass on pelvic rectal, and a biopsy through the vagina did confirm an HPV-associated squamous cell carcinoma. Because she was node positive, again, planned for chemoradiation with BrachyBoost. This is a particular patient that probably would have gotten a perineal implant to adequately implant this, but she was in her late 70s. Going through a perineal implant, and especially here, traveling to go do that, can be quite difficult. She elected to have treatment with us. We had to improvise. Okay, how are we going to effectively implant this? This is her time of brachytherapy, and it's a bit interesting. You can see from this actual MRI, this is one of the ovoids from the Geneva, and the other side, it's absent. What we did, we actually put a blunt tandem, because nothing to sound, and then one of the ovoids on the left side, where the tumor was, and then on the other side, just packed, so everything was held into place. Then within this lateral middle channel, a little bit more difficult to see, but on this sagittal MRI, we fed an interstitial needle right into the tumor. This is the transabdominal sagittal view, showing this needle going nicely into the tumor. Then on our post-treatment, or post-implant CT, you could see the needle into the mass, again, the blue depicting our target, or HRCTV, and then the red being our 100% isodose, nicely covering this, and avoiding the adjacent OARs. On her final dosimetry, her D90 that we achieved was in the high 80s, and again, OAR constraints below our hard cutoffs, so it just shows you that sometimes you can achieve good brachytherapy without a huge invasive implant, especially for patients in their late 70s, where that would be quite difficult to tolerate, and in our resource-limited setting, sometimes this is the alternative that we have to go with. Just some conclusions, and some tips, and what I've learned at Peter Mac is the pre-brachytherapy MRI is very helpful. They would do that not infrequently, especially for these complicated implants, and it just gives you another bit of information of how to plan what you're going to do during that fraction one, and you can do a lot of measurements on there of how deep you think you can go, and you can use that with your clinical exam, your ultrasound and time of fraction one, and everything should be concordant. I hope you learned that ultrasound guidance is key. The ultrasound program at Peter Mac with Sylvia Van Dyck and the entire team is second to none. They are really experts at all the different modalities, whether it be transabdominal, transrectal, transvaginal, and learning from that team has been excellent. What I really like about brachytherapy is, and I hope that I've depicted here, is really it's continuous learning, imagination, and creativity, sometimes trying new things, seeing how they work is how we adapt to challenges, and you really need to surround yourself with a team that's motivated to do that, to improve care to patients. Peter Mac is the epitome of that team. Thank you very much. Say hi to all my Australian colleagues, and thanks for allowing me to present today.

brachytherapy

ultrasound

gynecological

genitourinary

MRI