HDR Brachytherapy For Cervical Cancer Research Articles

Feasibility and Workflow Efficiency in MRI-Based HDR Brachytherapy for Cervical Cancer at a Community-Based Practice

Image-guided brachytherapy (IGBT) has seen widespread use in high-volume centers around the country in the last ten years. GEC-ESTRO recommendations stipulate that the dose be prescribed to the high-risk clinical target volume, which includes the residual tumor present at the time of brachytherapy. This practice has resulted in lesser normal tissue toxicity and improved local control. We introduced MRI volumetric planning at our center three years ago to confer this advantage to our patients. Based on a practice pattern survey by the American brachytherapy society in 2014, IGBT with MRI-based planning was grossly underutilized due to challenges associated with the work stream and availability of MRI. The combined mean procedure time for MR imaging and planning reported at a high-volume brachytherapy center was 63.2 minutes. Our study aimed to identify the time required for MRI-based IGBT for the first HDR fraction for cervical cancer patients at our institution. We aim to understand how we differ from a typical high-volume center and how we may improve our efficiency and workflow. Between 2020 and 2023, 14 patients were treated with HDR brachytherapy for a diagnosis of cervical cancer. Of these individuals, 7 patients were treated with MRI-guided IGBT during the first HDR fraction. The following time intervals were recorded: 1. Time from applicator insertion to completion of MRI imaging 2. Time from completion of MRI imaging to start of CT simulation 3. Time from start of CT simulation to completion of treatment delivery Materials and methods: Between 2020 and 2023, 14 patients were treated with HDR brachytherapy for a diagnosis of cervical cancer. Of these individuals, 7 patients were treated with MRI-guided IGBT during the First HDR fraction. The following time intervals were recorded: 1. Time from applicator insertion to completion of MRI imaging 2. Time from completion of MRI imaging to start of CT simulation 3. Time from start of CT simulation to completion of treatment delivery. The mean total procedure time was 582 minutes (Range 494- 665). The mean time and ranges for each phase were as follows. The mean time from the implant insertion to MRI completion was 157.7 minutes (Range 70-307), and the time from MRI completion to the start of CT simulation was 114.7 minutes (Range 17-173), and the time from the start of CT simulation to the treatment delivery was 310 minutes (Range 251-476). Our study demonstrates that MRI-based HDR brachytherapy with a skilled multidisciplinary team in a small community-based practice with an MRI imaging facility is a feasible approach similar to a high-volume center but differs in the total treatment time. Considering high treatment time in the community-based practice, the department is taking a team approach to improve efficiency. This includes establishing a dedicated brachytherapy suite closer to the MRI imaging and incorporating artificial intelligence to assist planning.

PD-0407 HDR brachytherapy for Cervical Cancer: Evolving anaesthetic technique to improve patient experience

PD-0407 HDR brachytherapy for Cervical Cancer: Evolving anaesthetic technique to improve patient experience

PD-0500 Dose prediction in HDR brachytherapy for cervical cancer using 3D transformer-based deep learning

PD-0500 Dose prediction in HDR brachytherapy for cervical cancer using 3D transformer-based deep learning

PO16: Commissioning of the Varian Universal Interstitial Cylinder (UIC) System for HDR Brachytherapy of Cervical Cancer

<h3>Purpose</h3> Varian Medical Systems (VMS) has recently released the Universal Interstitial Cylinder (UIC) for use with Ir-192 HDR brachytherapy. We commissioned one cylinder with a plastic Universal Cervix Probe (UPC) and plastic interstitial needles using CT and MR images. A phantom specifically designed to avoid the introduction of water or water-like materials into the needle guide tracks was used and various marker strands were investigated to accurately reconstruct source positions. <h3>Materials and Methods</h3> CT and MR scan were taken for the UIC set: one cylinder (30 mm diameter) with plastic UCP (80 mm, 30 degrees) and eight interstitial needles (channel #2-#9). To compare three different methods for channel identification, CT images (Siemens Biograph mCT, Siemens AG) with slice thickness of 0.6 mm were taken with either no radio opaque markers, VMS-numbered markers, or nylon coated stainless steel leader wires ("fish wire") which aid in channel identification and image registration. The MR images were taken on a 3T Magnetom Skyra Siemens MRI scanner using 3D T1 and 2D T2 weighted clinical HDR gynecological MRI protocols. An HDR MRI Lumen Marker (C4 Imaging, LLC) was placed in the channel #9 to check for any applicator rotation. The needle guide track openings at the distal end of the UIC cylinder causes liquid to be introduced into the tracks which results in unintended MR and CT signal. A gynecological phantom was constructed by placing the applicator set into three different phantom materials: wet towels, gelatin, or ground beef. Image quality of the CT and MRI scans for these phantoms were compared for treatment planning. The applicator dimensions were verified on CT and kV planar images. Dimensions from the vendor solid applicator models, which are based on the computer-aided design model files of the specific applicator were compared to those on CT and kV images. <h3>Results</h3> The phantoms made of wet towels or gelatin allowed significant amounts of liquid to enter the needle guide tracks from the holes in the distal end of the cylinder. This can mislead as to the actual source positions in the applicator. Specifically, it resulted in channels with unintended MR and CT signal (Figure 1a). The ground beef phantom was developed to limit this introduction of liquid into the cylinder (Figure 1b). CT scans with no markers displayed substantially wider needle guide tracks than the plastic needles (Figure 1b). CT scans with VMS-markers showed significant artifact (Figure 1c). CT scans with fish wire provided the best visibility of the needles within the needle guide tracks (Figure 1d). This scan along with the solid applicator model was also used to confirm distance from the outer wall to the inside of the needle guide track (8 mm) and to the center of the needle (7 mm) and the 30 mm diameter of the cylinder (Figure 1d). The use of an MR marker allowed that needle (channel #9) to be identified in the T1w MR scan (Figure 1b). The dimensions of the applicators could be validated on CT (Figure 1d) and kV planar images (Figure 1e). <h3>Conclusions</h3> The UIC applicator was commissioned for CT and MR image based treatment planning for HDR brachytherapy. Planar kV images verified dimensions of applicator against vendor specs. Accurate source position reconstruction was feasible using CT scan with 0.6 mm slice thickness and radio-opaque markers. The use of a ground beef phantom rather than a liquid based phantom minimized unintended MR and CT signal by limiting introduction of fluid into the needle guide tracks.

GSOR8 Presentation Time: 9:35 AM: Impact of External Beam Radiotherapy Site on Cervical Cancer Outcomes for Patients Undergoing Brachytherapy Boost at a Single Institution

<h3>Purpose</h3> For patients undergoing definitive radiation treatment for cervical cancer, historical evidence demonstrates that a delay in overall time to complete therapy beyond 7-9 weeks yields poorer survival outcomes. Moreover, retrospective data suggests that treatment with external beam radiotherapy (EBRT) and HDR brachytherapy at different institutions corresponds to increased likelihood of treatment delays and worse survival. It is unclear, however, whether these treatment-related factors continue to impact cervical cancer outcomes in contemporary cohorts with modern diagnostic imaging and treatment techniques. We investigated treatment-related factors and associated outcomes in a contemporary cohort of patients undergoing definitive radiation treatment for cervical cancer. <h3>Materials and Methods</h3> We conducted a retrospective cohort study using a single institution treatment database to identify patients who underwent HDR brachytherapy as part of definitive radiation treatment for cervical cancer between 2011 and 2021. Patients were categorized as having undergone EBRT at the same institution or at an outside facility. Patients who initially underwent surgery with hysterectomy were excluded. All patients underwent staging using PET and/or MRI imaging modalities and underwent MRI prior to HDR brachytherapy as well as CT and/or MRI with brachytherapy. We utilized Cox regression models to analyze the impact of treatment-related factors on recurrence-free and overall survival. <h3>Results</h3> The observational cohort included N = 138 patients with cervical cancer who underwent HDR brachytherapy as part of definitive radiation treatment during the study period including 64 (46.4%) who underwent EBRT at an outside facility. The majority of patients (72%) had FIGO 2018 Stage III or IV disease at diagnosis and median tumor size was 5.3 cm in greatest dimension (IQR: 4.0-6.5). Nearly all patients (95.6%) received concurrent chemotherapy. Median total treatment time was 50 days (IQR: 46-57). Patients who underwent outside EBRT were more likely to have a treatment delay of >8 weeks total treatment time (56% vs. 9%, p < 0.001). At a median follow up of 34 months, outside EBRT was not associated with a difference in recurrence-free survival (HR 0.97, 95% CI: 0.49-1.93) or overall survival (HR 0.96, 95% CI: 0.43-2.15) on univariate or multivariate analyses. Similarly, no difference in outcomes was observed when stratifying analyses by tumor size (> or < 5 cm) or stage at diagnosis. <h3>Conclusions</h3> In this observational cohort patients undergoing HDR brachytherapy for cervical cancer at a single institution, there was no difference in outcomes based on whether EBRT was delivered at the same facility despite outside EBRT being associated with increased total treatment time. Future prospective studies should investigate the optimal window of total treatment time for patients with cervical undergoing definitive radiation treatment in the era of modern diagnostic modalities, contemporary HDR technique, and concurrent chemotherapy.

PO-1791 Lumbosacral plexus dose with CT pelvimetry correlation in cervical cancer HDR brachytherapy

PO-1791 Lumbosacral plexus dose with CT pelvimetry correlation in cervical cancer HDR brachytherapy

PO-0203 Range of intra-fraction dose uncertainty in cervical cancer HDR brachytherapy.

PO-0203 Range of intra-fraction dose uncertainty in cervical cancer HDR brachytherapy.

PO-0225 Automatic reporting of vaginal dose points for cervical cancer HDR-brachytherapy

PO-0225 Automatic reporting of vaginal dose points for cervical cancer HDR-brachytherapy

OC-1042: Deep-learning based Physician’s Preference Prediction For HDR Brachytherapy Of Cervical Cancer

OC-1042: Deep-learning based Physician’s Preference Prediction For HDR Brachytherapy Of Cervical Cancer

Contour-Based Deformable Image Registration and Dose Accumulation in CT-based Hybrid HDR Brachytherapy for Cervical Cancer

Contour-Based Deformable Image Registration and Dose Accumulation in CT-based Hybrid HDR Brachytherapy for Cervical Cancer

Comparison of ICRU 38 rectal reference point dose estimates with measured dose in vivo in cobalt-60 HDR brachytherapy for cervical cancer

The objective of this study was to compare the ICRU 38 calculated rectal dose with in vivo dosimetry measured doses in cobalt-60 HDR brachytherapy for cervical cancer. A total of 48 brachytherapy insertions done on 15 patients treated from January to March 2017 at our institution were included in this prospective cross-sectional study. The results demonstrated no significant difference between the computed ICRU rectal point dose and in vivo maximum measured rectal dose ((r) 0.6208, p < 0.0001 [S]; t test p = 0.1578 [NS] 95% CI − 0.78 to 0.46), but a significant difference between ICRU rectal point and in vivo mean measured rectal dose ((r) 0.6033, p < 0.0001 [S]; t test p < 0.0001 [S] 95% CI − 0.81 to 0.35). These findings were seen even when sub-analyzed for the two used fraction sizes of 7 Gy and 8 Gy. The results also showed no significant differences in the maximum ((r) 0.9029, p < 0.0001 [S]; t test p = 0.2576 [NS], 95% CI − 0.21 to 0.06) and mean ((r) 0.9766, p < 0.0001 [S]; t test p = 0.2786 [NS], 95% CI − 0.93 to 0.03) doses taken from treatment planning system assigned dose points coinciding with the imaged probes of the in vivo dosimeter. Overall, this study was able to provide additional evidence that in vivo dosimetry can be validly used in the clinical setting to estimate the dose to the rectum during Co-60 HDR brachytherapy. Use of this technique allows for an additional quality assurance method that can contribute to reductions of errors in dose delivery.

PO-163: Outcomes after Co-60 HDR brachytherapy for cervical cancer in a tertiary hospital in the Philippines

PO-163: Outcomes after Co-60 HDR brachytherapy for cervical cancer in a tertiary hospital in the Philippines

PV-0141 Treatment outcomes of HDR brachytherapy for cervical cancer: a comparison of Ir-192 versus Co-60

PV-0141 Treatment outcomes of HDR brachytherapy for cervical cancer: a comparison of Ir-192 versus Co-60

Comparison of Spinal and General Anesthesia Approaches for MRI-guided Brachytherapy for Cervical Cancer

This study evaluates the impact of general vs spinal anesthesia on post-procedure narcotic use in HDR brachytherapy for cervical cancer and the effect of MRI-guided planning on treatment time for fractions utilizing spinal anesthesia.

EP-2216: The dosimetric impact of interstitial needles in HDR brachytherapy for cervical cancer

EP-2216: The dosimetric impact of interstitial needles in HDR brachytherapy for cervical cancer

Reduction of applicator displacement in MR/CT-guided cervical cancer HDR brachytherapy by the use of patient hover transport system.

PurposeTo quantify the reduction of relative displacement between the implanted intracavitary applicator and the patient bony anatomy, due to the use of a hover transport system during the patient transports between the imaging table and the treatment table.Material and methodsThe displacement of the applicator inside the patient was measured by comparing the distance between the tip of the tandem and the pubic bone on X-ray radiography images taken before and after moving a patient to magnetic resonance/computed tomography imaging. Displacements were evaluated for 27 fractions of treatment using hover transport and 185 fractions of treatment using manual transport.ResultsThe use of hover transport system reduced the percentage of fractions with displacements greater than 5 mm from 22.7% to 7.4%. The reduction of applicator displacement using hover transport is statistically significant, compared to the manual transport method (p-value 0.0086; mean displacement 3.41 mm [95% CI: 2.96-3.97] for manual transport, and 2.27 mm [95% CI: 1.71-2.97] for hover transport fractions).ConclusionsThis study indicates that the hover transport system is effectively reducing displacement between tandem and patient bony anatomy during patient transports. The potential improvement in dosimetric accuracy due to this reduction warrants further study.

A comparison between traditional packing and RadiaDyne balloon packing for patients receiving HDR brachytherapy for cervical cancer

A comparison between traditional packing and RadiaDyne balloon packing for patients receiving HDR brachytherapy for cervical cancer

Feasibility of Pneumo-Occluder Balloon in Place of Vaginal Packing During Ring and Tandem HDR Brachytherapy for Cervical Cancer

Feasibility of Pneumo-Occluder Balloon in Place of Vaginal Packing During Ring and Tandem HDR Brachytherapy for Cervical Cancer

Intracavitary versus Intracavitary/Interstitial HDR Brachytherapy for Cervical Cancer: Dose Difference to High Risk Clinical Target Volume

Intracavitary versus Intracavitary/Interstitial HDR Brachytherapy for Cervical Cancer: Dose Difference to High Risk Clinical Target Volume

PO-0941: Verifying the treatment planning system in individualized HDR brachytherapy of cervical cancer

PO-0941: Verifying the treatment planning system in individualized HDR brachytherapy of cervical cancer