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Objective . MRI is the standard imaging modality for high-dose-rate brachytherapy of cervical cancer. Precise contouring of organs at risk (OARs) and high-risk clinical target volume (HR-CTV) from MRI is a crucial step for radiotherapy planning and treatment. However, conventional manual contouring has limitations in terms of accuracy as well as procedural time. To overcome these, we propose a deep learning approach to automatically segment OARs (bladder, rectum, and sigmoid colon) and HR-CTV from female pelvic MRI. Approach . In the proposed pipeline, a coarse multi-organ segmentation model first segments all structures, from which a region of interest is computed for each structure. Then, each organ is segmented using an organ-specific fine segmentation model separately trained for each organ. To account for variable sizes of HR-CTV, a size-adaptive multi-model approach was employed. For coarse and fine segmentations, we designed a dual convolution-transformer UNet (DCT-UNet) which uses dual-path encoder consisting of convolution and transformer blocks. To evaluate our model, OAR segmentations were compared to the clinical contours drawn by the attending radiation oncologist. For HR-CTV, four sets of contours (clinical + three additional sets) were obtained to produce a consensus ground truth as well as for inter/intra-observer variability analysis. Main results . DCT-UNet achieved dice similarity coefficient (mean ± SD) of 0.932 ± 0.032 (bladder), 0.786 ± 0.090 (rectum), 0.663 ± 0.180 (sigmoid colon), and 0.741 ± 0.076 (HR-CTV), outperforming other state-of-the-art models. Notably, the size-adaptive multi-model significantly improved HR-CTV segmentation compared to a single-model. Furthermore, significant inter/intra-observer variability was observed, and our model showed comparable performance to all observers. Computation time for the entire pipeline per subject was 12.59 ± 0.79 s, which is significantly shorter than the typical manual contouring time of >15 min. Significance . These experimental results demonstrate that our model has great utility in cervical cancer brachytherapy by enabling fast and accurate automatic segmentation, and has potential in improving consistency in contouring. DCT-UNet source code is available athttps://github.com/JHU-MICA/DCT-UNet., (© 2024 Institute of Physics and Engineering in Medicine. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Purpose: To evaluate the relationship between delivered radiation (RT) and post-RT inversion-recovery ultrashort-echo-time (IR-UTE) MRI signal-intensity (SI) in gynecologic cancer patients treated with high-dose-rate (HDR) brachytherapy (BT)., Methods: Seven patients underwent whole-pelvis RT (WPRT) followed by BT to the high-risk clinical target volume (HR-CTV). MR images were acquired at three time-points; pre-RT, post-WPRT/pre-BT, and 3-6 months post-BT. Diffuse-fibrosis (F Diffuse ) was imaged with a non-contrast dual-echo IR (inversion time [TI] = 60 ms) UTE research application, with image-subtraction of the later echo, only retaining the ultrashort-echo SI. Dense-fibrosis (F Dense ) imaging utilized single-echo Late-Gadolinium-Enhanced IR-UTE, acquired ∼ 15 min post-Gadavist injection. Resulting F Diffuse and F Dense SI were normalized to the corresponding gluteal-muscle SI. Images were deformably registered between time-points based on normal tissue anatomy. The remnant tumor at both time-points was segmented using multi-parametric MRI. Contours corresponding to the 50%, 100%, 150%, and 200% isodose lines (IDLs) of the prescription BT-dose were created. Mean F Diffuse and F Dense SI within (i) each IDL contour and (ii) the remnant tumor were calculated. Post-BT F Diffuse and F Dense SI were correlated with prescribed BT-dose. To determine the relationship between BT-dose and IR-UTE SI, the differences in the post-BT F Dense across IDLs was determined using paired t-tests with Bonferroni correction., Results: F Dense was higher in regions of higher dose for 6/7 patients, with mean ± SD values of 357 ± 103% and 331 ± 97% (p = .03) in the 100% and 50% IDL, respectively. F Dense was higher in regions of higher dose in the responsive regions with mean ± SD values of 380 ± 122% and 356 ± 135% (p = .03) in the 150% and 50% IDL, respectively. Within the segmented remnant tumor, an increase in prescribed dose correlated with an increase in F Dense post-BT (n = 5, r = .89, p = .04). Post-BT F Diffuse inversely correlated (n = 7, r = -.83, p = .02) with prescribed BT-dose within the 100% IDL., Conclusions: Results suggest that F Dense SI 3-6 months post-BT is a sensitive measure of tissue response to heterogeneous BT radiation-dose. Future studies will validate whether F Diffuse and F Dense are accurate biomarkers of fibrotic radiation response., (© 2024. The Author(s).)

The use of brachytherapy for the treatment of gynecologic malignancies, particularly cervical cancer, has a long and rich history that is nearly as long as the history of radiation oncology itself. From the first gynecologic brachytherapy treatments in the early 20th century to the modern era, significant transformation has occurred driven largely by advancements in technology. The development of high-dose rate sources, remote afterloaders, novel applicators, and 3-dimensional image guidance has led to improved local control, and thus improved survival, solidifying the role of brachytherapy as an integral component in the treatment of locally advanced cervical cancer. Current research efforts examining novel magnetic resonance imaging sequences, active magnetic resonance tracking, and the application of hydrogel aim to further improve local control and reduce treatment toxicity., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: The MRI-guided cervical cancer brachytherapy provides unparalleled soft-tissue contrast for target and normal tissue contouring, but eliminates the ability to use conventional metallic fiducials for radiation source path reconstruction as required for treatment planning. Instead, the source path is reconstructed by manually aligning a library model to the signal void produced by the applicator, which takes time intraoperatively and precludes fully automated treatment planning. The purpose of this study is to present and validate an algorithm to automatically reconstruct tandem and ring applicators using MRI for cervical cancer brachytherapy treatment planning., Methods: Applicators were reconstructed using T2-weighted MR images acquired at 1.5 T from 33 brachytherapy fractions including 10 patients using a model-to-image registration algorithm. The algorithm involves (a) image filtering and maximum intensity projection to highlight the applicator, (b) ring center identification using the circular Hough transform, and (c) three-dimensional surface model registration, optimized by maximizing the image intensity gradient normal to the model surface. Two independent observers manually reconstructed all applicators, enabling the calculation of interobserver variability and establishing a ground truth. Algorithm variability was calculated by comparing algorithm results to each individual observer, and algorithm accuracy was calculated by comparing algorithm results to the ground truth. The algorithm variability and accuracy were compared to the interobserver variability using paired t-tests., Results: Mean ± SD interobserver variability was 0.83 ± 0.31 mm and 0.78 ± 0.29 mm for the ring and tandem, respectively. The algorithm had mean ± SD variability and accuracy of 0.72 ± 0.32 mm (P = 0.02) and 0.60 ± 0.24 mm (P = 0.0005) for the ring, and 0.70 ± 0.29 mm (P = 0.11) and 0.58 ± 0.24 mm (P = 0.004) for the tandem, respectively., Conclusions: The algorithm variability and accuracy were within the interobserver variability measured in this study. The algorithm accuracy and mean execution time of 10.0 s are sufficient for clinical tandem and ring reconstruction, and are a step toward fully automated tandem and ring brachytherapy treatment planning., (© 2019 American Association of Physicists in Medicine.)

Objective: The purpose was to compare local control (LC), overall survival (OS) and dose to the organs at risk (OAR) in women with locally advanced cervical cancer treated with MR-guided versus CT-guided interstitial brachytherapy (BT)., Methods: 56 patients (29 MR, 27 CT) were treated with high-dose-rate (HDR) interstitial BT between 2005-2015. The MR patients had been prospectively enrolled on a Phase II clinical trial. Data were analyzed using Kaplan-Meier (K-M) and Cox proportional hazards statistical modeling in JMP® & R®., Results: Median follow-up time was 19.7months (MR group) and 18.4months (CT group). There were no statistically significant differences in patient age at diagnosis, histology, percent with tumor size >4cm, grade, FIGO stage or lymph node involvement between the groups. Patients in the MR group had more lymphovascular involvement compared to patients in the CT group (p<0.01). When evaluating plans generated, there were no statistically significant differences in median cumulative dose to the high-risk clinical target volume or the OAR. 2-year K-M LC rates for MR-based and CT-based treatments were 96% and 87%, respectively (log-rank p=0.65). At 2years, OS was significantly better in the MR-guided cohort (84% vs. 56%, p=0.036). On multivariate analysis, squamous histology was associated with longer OS (HR 0.23, 95% CI 0.07-0.72) in a model with MR BT (HR 0.35, 95% CI 0.08-1.18). There was no difference in toxicities between CT and MR BT., Conclusion: In this population of locally advanced cervical-cancer patients, MR-guided HDR BT resulted in estimated 96% 2-year local control and excellent survival and toxicity rates., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To assess whether R2* mapping with a standard Monoexponential (ME) or a Gaussian Augmentation of the Monoexponential (GAME) decay model better characterizes gradient-echo signal decays in gynecological cancers after external beam radiation therapy at 3T, and evaluate implications of modeling for noninvasive identification of intratumoral hypoxia., Materials and Methods: Multi-gradient-echo signals were acquired on 25 consecutive patients with gynecologic cancers and three healthy participants during inhalation of different oxygen concentrations at 3T. Data were fitted with both ME and GAME models. Models were compared using F-tests in tumors and muscles in patients, muscles, cervix, and uterus in healthy participants, and across oxygenation levels., Results: GAME significantly improved fitting over ME (P < 0.05): Improvements with GAME covered 34% of tumor regions-of-interest on average, ranging from 6% (of a vaginal tumor) to 68% (of a cervical tumor) in individual tumors. Improvements with GAME were more prominent in areas that would be assumed hypoxic based on ME alone, reaching 90% as ME R2* approached 100 Hz. Gradient echo decay parameters at different oxygenation levels were not significantly different (P = 0.81)., Conclusion: R2* may prove sensitive to hypoxia; however, inaccurate representations of underlying data may limit the success of quantitative assessments. Although the degree to which R2 or σ values correlate with hypoxia remains unknown, improved characterization with GAME increases the potential for determining any correlates of fit parameters with biomarkers, such as oxygenation status. J. MAGN. RESON. IMAGING 2016;44:1020-1030., (© 2016 International Society for Magnetic Resonance in Medicine.)

Purpose: In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization using magnetic resonance imaging (MRI) and CT., Methods: The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter's trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High-resolution 3D MRI of the phantom was performed followed by catheter digitization based on the catheter's imaging artifacts. The catheter trajectory error was characterized in terms of the mean distance between corresponding dwell points in MRTR-generated catheter trajectory and MRI-based catheter digitization. The MRTR-based catheter trajectory reconstruction process was also performed on three gynecologic cancer patients, and then compared with catheter digitization based on MRI and CT., Results: The catheter tip localization error increased as the MRTR stylet moved further off-center and as the stylet's orientation deviated from the main magnetic field direction. Fifteen catheters' trajectories were reconstructed by MRTR. Compared with MRI-based digitization, the mean 3D error of MRTR-generated trajectories was 1.5 ± 0.5 mm with an in-plane error of 0.7 ± 0.2 mm and a tip error of 1.7 ± 0.5 mm. MRTR resolved ambiguity in catheter assignment due to crossed catheter paths, which is a common problem in image-based catheter digitization. In the patient studies, the MRTR-generated catheter trajectory was consistent with digitization based on both MRI and CT., Conclusions: The MRTR system provides accurate catheter tip localization and trajectory reconstruction in the MR environment. Relative to the image-based methods, it improves the speed, safety, and reliability of the catheter trajectory reconstruction in interstitial brachytherapy. MRTR may enable in-procedural dosimetric evaluation of implant target coverage.

Purpose: The purpose of this study was to assess variability in contouring the gross tumor volume (GTV) and clinical target volume (CTV) of 3 clinical cervix cancer cases by a cohort of international experts in the field in preparation for the development of an online teaching atlas., Methods and Materials: Twelve international experts participated. Three clinical scenarios: node positivity (PLN), retroverted uterus (RV), and parametrial invasion (PI) were used. Sagittal and axial magnetic resonance images of the clinical cases were downloaded to participants' treatment planning systems for contouring. The GTV/cervix/uterus/parametria/vagina and nodal CTV were contoured. Contour consensus was assessed for sensitivity/specificity using an expectation maximization algorithm called Simultaneous Truth and Performance Level Estimation and experts' overall agreement was summarized by kappa statistics., Results: Agreement for GTV in the 3 clinical cases was high (Simultaneous Truth and Performance Level Estimation sensitivity, 0.54-0.92; specificity, 0.97-0.98; and kappa measure for PLN, RV, and PI was 0.86, 0.76, and 0.42; P < .0001). Moderate to substantial agreement was seen for nodal CTV (kappa statistics for PLN, RV, and PI was 0.65, 0.58, and 0.62; P < .0001), uterus (kappa for PLN, RV, and PI was 0.45, 0.74, and 0.77; P < .0001), and parametria (kappa for PLN, RV, and PI was 0.49, 0.62, and 0.50; P < .0001). Contouring heterogeneity was greatest for the cervix (kappa measure for PLN, RV, and PI was 0.15, 0.4, and 0.24; P < .0001) and vagina (kappa for PLN, RV, and PI was 0.47, 0.36 and 0.46; P < .0001), reflecting difficulties in determining the interface between GTV and these tissues., Conclusion: Kappa statistics of the different CTV components generally demonstrated moderate to substantial agreement among international experts in the field of gynecological radiation therapy. Further planning target volume margins accounting for organ motion and setup errors are a necessary addition to the CTV., (Copyright © 2015. Published by Elsevier Inc.)

Purpose: The purpose of this consensus statement from the American Brachytherapy Society (ABS) is to summarize recent advances and to generate general guidelines for the management of medically inoperable endometrial cancer patients with radiation therapy., Methods: Recent advances in the literature were summarized and reviewed by a panel of experts. Panel members participated in a series of conference calls and were surveyed to determine their current practices and patterns. This document was reviewed and approved by the full panel, the ABS Board of Directors and the ACR Commission on Radiation Oncology., Results: A transition from two-dimensional (2D) to three-dimensional (3D) treatment planning for the definitive treatment of medically inoperable endometrial cancer is described. Magnetic resonance (MR) imaging can be used to define the gross tumor volume (GTV), clinical target volume (CTV), and the organs at risk (OARs). Brachytherapy alone can be used for medically inoperable endometrial cancer patients with clinical Stage I cancer with no lymph node involvement and no evidence of deep invasion of the myometrium on MR imaging. In the absence of MR imaging, a combined approach using external beam and brachytherapy may be considered., Conclusions: Recent advances support the use of MR imaging and 3D planning for brachytherapy treatment for medically inoperable endometrial cancer., (Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)

Purpose: To develop an active MR-tracking system to guide placement of metallic devices for radiation therapy., Methods: An actively tracked metallic stylet for brachytherapy was constructed by adding printed-circuit micro-coils to a commercial stylet. The coil design was optimized by electromagnetic simulation, and has a radio-frequency lobe pattern extending ∼5 mm beyond the strong B0 inhomogeneity region near the metal surface. An MR-tracking sequence with phase-field dithering was used to overcome residual effects of B0 and B1 inhomogeneities caused by the metal, as well as from inductive coupling to surrounding metallic stylets. The tracking system was integrated with a graphical workstation for real-time visualization. The 3 Tesla MRI catheter-insertion procedures were tested in phantoms and ex vivo animal tissue, and then performed in three patients during interstitial brachytherapy., Results: The tracking system provided high-resolution (0.6 × 0.6 × 0.6 mm(3) ) and rapid (16 to 40 frames per second, with three to one phase-field dithering directions) catheter localization in phantoms, animals, and three gynecologic cancer patients., Conclusion: This is the first demonstration of active tracking of the shaft of metallic stylet in MR-guided brachytherapy. It holds the promise of assisting physicians to achieve better targeting and improving outcomes in interstitial brachytherapy., (© 2014 Wiley Periodicals, Inc.)

Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy., Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case., Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR., Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The application of magnetic resonance image (MRI)-guided brachytherapy has demonstrated significant growth during the past 2 decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and resulted in mounting evidence of improved clinical outcome regarding local control, overall survival as well as morbidity. MRI-guided prostate high-dose-rate and low-dose-rate brachytherapies have improved the accuracy of target and organs-at-risk delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high-quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: To present outcome and toxicity results of the first real-time intraoperative MRI-guided interstitial approach to gynecologic cancer., Methods and Materials: From February 2004 to December 2006, 25 patients with gynecologic malignancies were enrolled and treated in a prospective clinical trial of real-time MRI-guided interstitial brachytherapy. This was followed by a confirmatory CT imaging scan. Statistical analyses included Kaplan-Meier estimates for overall and relapse-free survival., Results: MRI visualization of needles during placement permitted accurate placement with no inadvertent insertions. This prevented unnecessary normal-tissue perforation as confirmed by CT simulation. With a mean followup of 3.8 years (range, 2-6.8), 1-, 2-, and 3-year overall survival rates were 80%, 60% and 43%, respectively; corresponding relapse-free survival rates were 79%, 65%, and 59%, respectively. Actuarial acute toxicity rates for any grade were 0% at 0-14 days and 80% (all grade 1) at 14-90 days. Long-term (>180 days) actuarial toxicity rates were 8% gastrointestinal, 4% bladder and 4% vaginal., Conclusions: Real-time MRI guidance during insertion of interstitial needles followed by 3D-planning maximized opportunities for tumor targeting and sparing of normal tissues. Although image guidance requires additional anesthesia time, clinical outcomes indicate potential for a successful reduction in toxicity using 3D image-guided in addition to 3D image-planned brachytherapy., (Copyright © 2013 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)

Gynecologic malignancies are a leading cause of death in women worldwide. Standard treatment for many primary and recurrent gynecologic cancer cases includes external-beam radiation followed by brachytherapy. Magnetic resonance (MR) imaging is beneficial in diagnostic evaluation, in mapping the tumor location to tailor radiation dose and in monitoring the tumor response to treatment. Initial studies of MR guidance in gynecologic brachytherapy demonstrate the ability to optimize tumor coverage and reduce radiation dose to normal tissues, resulting in improved outcomes for patients. In this article, we describe a methodology to aid applicator placement and treatment planning for 3 Tesla (3-T) MR-guided brachytherapy that was developed specifically for gynecologic cancers. This methodology has been used in 18 cases from September 2011 to May 2012 in the Advanced Multimodality Image Guided Operating (AMIGO) suite at Brigham and Women's Hospital. AMIGO comprises state-of-the-art tools for MR imaging, image analysis and treatment planning. An MR sequence using three-dimensional (3D)-balanced steady-state free precession in a 3-T MR scanner was identified as the best sequence for catheter identification with ballooning artifact at the tip. 3D treatment planning was performed using MR images. Items in development include software designed to support virtual needle trajectory planning that uses probabilistic bias correction, graph-based segmentation and image registration algorithms. The results demonstrate that 3-T MR image guidance has a role in gynecologic brachytherapy. These novel developments have the potential to improve targeted treatment to the tumor while sparing the normal tissues., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: Accurate target definition is vitally important for definitive treatment of cervix cancer with intensity-modulated radiotherapy (IMRT), yet a definition of clinical target volume (CTV) remains variable within the literature. The aim of this study was to develop a consensus CTV definition in preparation for a Phase 2 clinical trial being planned by the Radiation Therapy Oncology Group., Methods and Materials: A guidelines consensus working group meeting was convened in June 2008 for the purposes of developing target definition guidelines for IMRT for the intact cervix. A draft document of recommendations for CTV definition was created and used to aid in contouring a clinical case. The clinical case was then analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants., Results: Nineteen experts in gynecological radiation oncology generated contours on axial magnetic resonance images of the pelvis. Substantial STAPLE agreement sensitivity and specificity values were seen for gross tumor volume (GTV) delineation (0.84 and 0.96, respectively) with a kappa statistic of 0.68 (p < 0.0001). Agreement for delineation of cervix, uterus, vagina, and parametria was moderate., Conclusions: This report provides guidelines for CTV definition in the definitive cervix cancer setting for the purposes of IMRT, building on previously published guidelines for IMRT in the postoperative setting., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Purpose: To compare the contours and dose-volume histograms (DVH) of the tumor and organs at risk (OAR) with computed tomography (CT) vs. magnetic resonance imaging (MRI) in cervical cancer brachytherapy., Methods and Materials: Ten patients underwent both MRI and CT after applicator insertion. The dose received by at least 90% of the volume (D(90)), the minimal target dose (D(100)), the volume treated to the prescription dose or greater for tumor for the high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) and the dose to 0.1 cm3, 1 cm3, and 2 cm3 for the OARs were evaluated. A standardized approach to contouring on CT (CT(Std)) was developed, implemented (HR- and IR-CTV(CTStd)), and compared with the MRI contours., Results: Tumor height, thickness, and total volume measurements, as determined by either CT or CT(Std) were not significantly different compared with the MRI volumes. In contrast, the width measurements differed in HR-CTV(CTStd) (p = 0.05) and IR-CTV(CTStd) (p = 0.01). For the HR-CTV(CTStd), this resulted in statistically significant differences in the volume treated to the prescription dose or greater (MRI, 96% vs. CT(Std), 86%, p = 0.01), D(100) (MRI, 5.4 vs. CT(Std), 3.4, p <0.01), and D(90) (MRI, 8.7 vs. CT(Std), 6.7, p <0.01). Correspondingly, the IR-CTV DVH values on MRI vs. CT(Std), differed in the D(100) (MRI, 3.0 vs. CT(Std), 2.2, p = 0.01) and D(90) (MRI, 5.6 vs. CT(Std), 4.6, p = 0.02). The MRI and CT DVH values of the dose to 0.1 cm3, 1 cm3, and 2 cm3 for the OARs were similar., Conclusion: Computed tomography-based or MRI-based scans at brachytherapy are adequate for OAR DVH analysis. However, CT tumor contours can significantly overestimate the tumor width, resulting in significant differences in the D(90), D(100), and volume treated to the prescription dose or greater for the HR-CTV compared with that using MRI. MRI remains the standard for CTV definition.

Purpose: To evaluate the feasibility and to describe the acute toxicity of a real-time intraoperative magnetic resonance (MR)-image guided interstitial approach to treating vaginal recurrence of endometrial cancer., Methods and Materials: From February 2004 to April 2005, 10 patients with recurrent endometrial cancer underwent MR-guided interstitial brachytherapy. Parameters evaluated included needle placement, dose-volume histograms (DVH), and complications., Results: Magnetic resonance-image guidance resulted in accurate needle placement. Tumor DVH values included median volume, 47 cc; V100, 89%; V150, 61%; V200, 38%; D90, 71 Gy; and D100, 60 Gy. DVH of organs at risk resulted in a median D2cc of external beam and brachytherapy dose (% of brachytherapy prescription): bladder, 75Gy(3) (88%); rectum, 70Gy(3) (87%); and sigmoid, 56Gy(3) (41%). All patients experienced either a Grade 1 or 2 acute toxicity related to the radiation; only 1 patient had Grade 3 toxicity. No toxicities were attributable to the use of MR guidance., Conclusions: Real-time MR guidance during the insertion of interstitial needles reduces the likelihood of an inadvertent insertion of the needles into the bladder and the rectum. Three-dimensional dosimetry allows estimation of the dose to organs at risk. Toxicities are limited.

Simple Summary: Current treatment options for advanced cervical cancer are limited, with a 5-year overall survival rate of 17%. New effective therapeutic approaches that can increase survival and reduce disparities are greatly needed. In this study, an approach using a multifunctional liquid immunogenic fiducial eluter (LIFE) that can provide image contrast and enhance therapeutic efficacy during hypo-fractionated radiotherapy is investigated. We found this technique provides both computed tomography (CT) and magnetic resonance imaging (MRI) image contrast to guide radiotherapy. Additionally, in a model of metastatic cervical cancer, local treatment with LIFE and radiotherapy resulted in distant disease control and improvement in survival. Successful development of this approach may provide a short therapeutic option that could enhance treatment outcomes and reduce disparities. LIFE Biomaterial may also significantly provide a cheaper and convenient alternative to prolonged systemic treatment with opportunities to increase access to care and reduce health outcome disparities. Globally, cervical cancer is the fourth leading cancer among women and is dominant in resource-poor settings in its occurrence and mortality. This study focuses on developing liquid immunogenic fiducial eluter (LIFE) Biomaterial with components that include biodegradable polymers, nanoparticles, and an immunoadjuvant. LIFE Biomaterial is designed to provide image guidance during radiotherapy similar to clinically used liquid fiducials while enhancing therapeutic efficacy for advanced cervical cancer. C57BL6 mice were used to grow subcutaneous tumors on bilateral flanks. The tumor on one flank was then treated using LIFE Biomaterial prepared with the immunoadjuvant anti-CD40, with/without radiotherapy at 6 Gy. Computed tomography (CT) and magnetic resonance (MR) imaging visibility were also evaluated in human cadavers. A pharmacodynamics study was also conducted to assess the safety of LIFE Biomaterial in healthy C57BL6 female mice. Results showed that LIFE Biomaterial could provide both CT and MR imaging contrast over time. Inhibition in tumor growth and prolonged significant survival (* p < 0.05) were consistently observed for groups treated with the combination of radiotherapy and LIFE Biomaterial, highlighting the potential for this strategy. Minimal toxicity was observed for healthy mice treated with LIFE Biomaterial with/without anti-CD40 in comparison to non-treated cohorts. The results demonstrate promise for the further development and clinical translation of this approach to enhance the survival and quality of life of patients with advanced cervical cancer. [ABSTRACT FROM AUTHOR]

A middle-aged male with end-stage renal disease underwent cadaveric transplantation. Intraoperatively, a large mass was seen in the pelvis surrounding the vessels, native ureter, and bladder. Ultrasound showed echogenic fatty tissue in the pelvis suggestive of pelvic lipomatosis vessels were dissected, layers were separated with a lot of difficulty. The urinary bladder could not be defined. Hence, ureteroureterostomy was done and a DJ stent was placed. The patient had immediate graft function and attained a nadir creatinine of 0.6 mg/dl on postoperative day 6. [ABSTRACT FROM AUTHOR]

Purpose: Contouring clinical target volume (CTV) from medical images is an essential step for radiotherapy (RT) planning. Magnetic resonance imaging (MRI) is used as a standard imaging modality for CTV segmentation in cervical cancer due to its superior soft‐tissue contrast. However, the delineation of CTV is challenging as CTV contains microscopic extensions that are not clearly visible even in MR images, resulting in significant contour variability among radiation oncologists depending on their knowledge and experience. In this study, we propose a fully automated deep learning–based method to segment CTV from MR images. Methods: Our method begins with the bladder segmentation, from which the CTV position is estimated in the axial view. The superior–inferior CTV span is then detected using an Attention U‐Net. A CTV‐specific region of interest (ROI) is determined, and three‐dimensional (3‐D) blocks are extracted from the ROI volume. Finally, a CTV segmentation map is computed using a 3‐D U‐Net from the extracted 3‐D blocks. Results: We developed and evaluated our method using 213 MRI scans obtained from 125 patients (183 for training, 30 for test). Our method achieved (mean ± SD) Dice similarity coefficient of 0.85 ± 0.03 and the 95th percentile Hausdorff distance of 3.70 ± 0.35 mm on test cases, outperforming other state‐of‐the‐art methods significantly (p‐value < 0.05). Our method also produces an uncertainty map along with the CTV segmentation by employing the Monte Carlo dropout technique to draw physician's attention to the regions with high uncertainty, where careful review and manual correction may be needed. Conclusions: Experimental results show that the developed method is accurate, fast, and reproducible for contouring CTV from MRI, demonstrating its potential to assist radiation oncologists in alleviating the burden of tedious contouring for RT planning in cervical cancer. [ABSTRACT FROM AUTHOR]

Purpose: Brachytherapy combined with external beam radiotherapy (EBRT) is the standard treatment for cervical cancer and has been shown to improve overall survival rates compared to EBRT only. Magnetic resonance (MR) imaging is used for radiotherapy (RT) planning and image guidance due to its excellent soft tissue image contrast. Rapid and accurate segmentation of organs at risk (OAR) is a crucial step in MR image‐guided RT. In this paper, we propose a fully automated two‐step convolutional neural network (CNN) approach to delineate multiple OARs from T2‐weighted (T2W) MR images. Methods: We employ a coarse‐to‐fine segmentation strategy. The coarse segmentation step first identifies the approximate boundary of each organ of interest and crops the MR volume around the centroid of organ‐specific region of interest (ROI). The cropped ROI volumes are then fed to organ‐specific fine segmentation networks to produce detailed segmentation of each organ. A three‐dimensional (3‐D) U‐Net is trained to perform the coarse segmentation. For the fine segmentation, a 3‐D Dense U‐Net is employed in which a modified 3‐D dense block is incorporated into the 3‐D U‐Net‐like network to acquire inter and intra‐slice features and improve information flow while reducing computational complexity. Two sets of T2W MR images (221 cases for MR1 and 62 for MR2) were taken with slightly different imaging parameters and used for our network training and test. The network was first trained on MR1 which was a larger sample set. The trained model was then transferred to the MR2 domain via a fine‐tuning approach. Active learning strategy was utilized for selecting the most valuable data from MR2 to be included in the adaptation via transfer learning. Results: The proposed method was tested on 20 MR1 and 32 MR2 test sets. Mean ± SD dice similarity coefficients are 0.93 ± 0.04, 0.87 ± 0.03, and 0.80 ± 0.10 on MR1 and 0.94 ± 0.05, 0.88 ± 0.04, and 0.80 ± 0.05 on MR2 for bladder, rectum, and sigmoid, respectively. Hausdorff distances (95th percentile) are 4.18 ± 0.52, 2.54 ± 0.41, and 5.03 ± 1.31 mm on MR1 and 2.89 ± 0.33, 2.24 ± 0.40, and 3.28 ± 1.08 mm on MR2, respectively. The performance of our method is superior to other state‐of‐the‐art segmentation methods. Conclusions: We proposed a two‐step CNN approach for fully automated segmentation of female pelvic MR bladder, rectum, and sigmoid from T2W MR volume. Our experimental results demonstrate that the developed method is accurate, fast, and reproducible, and outperforms alternative state‐of‐the‐art methods for OAR segmentation significantly (p < 0.05). [ABSTRACT FROM AUTHOR]

Purpose: To develop an endovaginal MRI array that provides signal enhancement forward into the posterior parametrium and sideways into the vaginal wall, accelerating multiple‐contrast detection of residual tumors that survive external beam radiation. The array's enclosure should form an obturator for cervical cancer brachytherapy, allowing integration with MRI‐guided catheter placement, CT, and interstitial radiation dose delivery. Methods: The endovaginal array consisted of forward‐looking and sideways‐looking components. The forward‐looking element imaged the cervix and posterior endometrium, and the sideways‐looking elements imaged the vaginal wall. Electromagnetic simulation was performed to optimize the geometry of a forward‐looking coil placed on a conductive‐metallic substrate, extending the forward penetration above the coil's tip. Thereafter, an endovaginal array with one forward‐looking coil and four sideways‐looking elements was constructed and tested at 1.5 Tesla in saline and gel phantoms, and three sexually mature swine. Each coil's tuning, matching, and decoupling were optimized theoretically, implemented with electronic circuits, and validated with network‐analyzer measurements. The array enclosure emulates a conventional brachytherapy obturator, allowing use of the internal imaging array together with tandem coils and interstitial catheters, as well as use of the enclosure alone during CT and radiation delivery. To evaluate the receive magnetic field (B1−) spatial profile, the endovaginal array's specific absorption‐rate (SAR) distribution was simulated inside a gel ASTM phantom to determine extreme heating locations in advance of a heating test. Heating tests were then performed during high SAR imaging in a gel phantom at the predetermined locations, testing compliance with MRI safety standards. To assess array imaging performance, signal‐to‐noise‐ratios (SNR) were calculated in a saline phantom and in vivo. Swine images were acquired with the endovaginal array combined with the scanner's body and spine arrays. Results: Simulated B1− profiles for the forward‐looking lobe pattern, obtained while varying several geometric parameters, disclosed that a forward‐looking coil placed on a metal‐backed substrate could double the effective forward penetration from approximately 25 to ∼40 mm. An endovaginal array, enclosed in an obturator enclosure was then constructed, with all coils tuned, matched, and decoupled. The ASTM gel‐phantom SAR test showed that peak local SAR was 1.2 W/kg in the forward‐looking coil and 0.3 W/kg in the sideways‐looking elements, well within ASTM/FDA/IEC guidelines. A 15‐min 4 W/kg average SAR imaging experiment resulted in less than 2oC temperature increase, also within ASTM/FDA/IEC heating limits. In a saline phantom, the forward‐looking coil and sideways‐looking array's SNR was four to eight times, over a 20–30 mm field‐of‐view (FOV), and five to eight times, over a 15–25 mm FOV, relative to the spine array's SNR, respectively. In three sexually mature swine, the forward‐looking coil provided a 5 + 0.2 SNR enhancement factor within the cervix and posterior endometrium, and the sideways‐looking array provided a 4 + 0.2 SNR gain factor in the vaginal wall, relative to the Siemens spine array, demonstrating that the array could significantly reduce imaging time. Conclusions: Higher SNR gynecological imaging is supported by forward‐looking and sideways‐looking coils. A forward‐looking endovaginal coil for cervix and parametrium imaging was built with optimized metal backing. Array placement within an obturator enhanced integration with the brachytherapy procedure and accelerated imaging for detecting postexternal‐beam residual tumors. [ABSTRACT FROM AUTHOR]

Active magnetic resonance (MR) tracking for gynecologic brachytherapy was made possible by attaching the microradiofrequency coils to the brachytherapy applicator. The rectangular planar microcoil was fabricated using flexible printed circuits with dimensions of 8 mm × 1.5 mm. A 5-Fr (1.6 mm) tungsten brachytherapy stylet was custom-machined to incorporate the microcoils. The finite element analysis and the phantom tissue studies show that the proposed device enables in situ real-time guidance of access routes to the target anatomy safely and accurately. The setup was tested in a Siemens 3T MR scanner. The microcoils can be localized rapidly (up to 40 Hz) and precisely (resolution: 0.6 mm × 0.6 mm × 0.6 mm) using an MR-tracking sequence. [ABSTRACT FROM PUBLISHER]

We report on recurrence patterns and prognostic features among pts treated definitively for primary vaginal cancer with placement of interstitial catheters in a magnetic resonance (MR) simulator and treatment in an adjacent brachytherapy suite. The cohort included 53 pts receiving radiotherapy (RT) for primary vaginal cancer from 9/2016-1/2022 at a single institution. Pts received external beam radiation (EBRT) plus high-dose rate brachytherapy (HDR-BT) (w/ MR guidance, Espree, Siemens, Inc.), or HDR-BT alone in the following settings: prior history of anal cancer s/p RT, early stage I, multiple co-morbidities w/ severe colitis or limited life expectancy. HDR-BT was delivered via Syed interstitial template or multichannel cylinder. Pre-procedure, pts had MR (T1-, T2-, diffusion-weighted, and dynamic contrast enhance) imaging to determine applicator required for ideal coverage. Interstitial HDR-BT pts had catheters placed in the MR room. Sequences performed post applicator insertion included T2-Space and high-res T2. Contouring of gross tumor volume (GTV), clinical target volume (CTV) of vagina, additional gynecologic organs if present (uterus, cervix), and normal tissues was performed based on an internal protocol. Interstitial cases had a subsequent CT scan to validate catheter digitization. Patient characteristics, treatment toxicity, and prognostic markers were analyzed. Kaplan-Meier (KM) estimates were generated for disease-free survival (DFS), local control (LC), and overall survival (OS). 41 pts were included. Median age was 61 yrs (range 33 - 90); median follow up was 28 months. Stage: FIGO I - 9 (22%), FIGO II - 11 (26.8%), FIGO III - 9 (22%), FIGO IV - 7 (17%), and recurrent - 5 (12.2%). 30 pts (73%) were squamous cell carcinoma, 5 pts (12.2%) were adenocarcinoma. RT with both EBRT+HDR-BT was done in 35 (85.4%) cases. 6 (14.6%) pts received HDR-BT alone. Syed interstitial implant was used for 40 (97.5%); 1 received multichannel cylinder. 33 (80%) received concurrent systemic therapy, primarily with cisplatin (24 pts). Median MR-defined CTV volume was 19.9 cm3 (range 0.77 cm3 - 202.1 cm3). Among the pts with a measurable lesion on MRI, median pre-RT tumor size was 4.5 cm (range 1.2-16.6cm). Median size at 3-month MR was 2.8 cm (range 1.3-13.3cm). Among pts who received EBRT+HDR-BT, median total D90 EQD2 was 70.2 Gy (range 56.6-91.5Gy). Median bladder, rectum, sigmoid, and bowel total EQD2 were 62.7 Gy (range 47.9-88Gy), 59.8 Gy (range 50.7-83.5Gy), 50.3 Gy (range 39.7-78.4Gy), and 50.1 Gy (range 43.2-89.9Gy), respectfully. For the pts who received HDR-BT only, median D90 EQD2 was 39.1 Gy (range 14.3-74.5Gy). Median bladder, rectum, sigmoid, and bowel EQD2 were 24.4 Gy (range 6.7-50.5Gy), 33.6 Gy (range 2.2-37.6Gy), 9 Gy (range 1.7-20.6Gy), and 2.4 Gy (range 2.3-28.3Gy). 12 pts progressed, none with local-only failure. 6 pts (46% of recurrences) progressed in multiple sites at recurrence. Disease spread distribution includes: Distant only = 7, distant+local = 2, regional LN only = 2, regional LN+local = 1. Sites of distant recurrence were lung (5), liver (3), and brain (4). Of these recurrences, 2 were in the HDR-BT only group (liver only and lung + local) and the remaining were in the EBRT + HDR BT group. For the entire cohort, 1 year OS was 82%, 2-year OS was 67%, and median OS was 5 years. 2-year DFS was 78% and 2-year LC was 93%. For the EBRT + HDR BT cohort vs. HDR-BT only cohort, 1 year OS was 80% vs. 66%, 2-year OS was 51% vs. 50%, 2-year DFS was 77% vs. 66%, and 2-year LC was 94% vs. 83%, respectively. The most common any grade treatment-related toxicity at 90-day follow up was vaginal pain, experienced by 15/40 pts. At 180-day follow up, this decreased to 8/32 pts. 6 (14.6%) pts experienced Grade 3 toxicity; 2 treated with argon laser ablation for rectal bleeding, 2 with hyperbaric oxygen for vaginal necrosis, 1 with colostomy + ileal conduit for colovesicular+colovaginal fistula, and 1 with surgical dilation for severe vaginal stenosis. In this series, MR-guided HDR-BT for primary vaginal cancer yields high rates of local control with limited grade 3+ toxicities, but lower rates of distant control indicate consideration for systemic therapy is warranted. [ABSTRACT FROM AUTHOR]

To report procedure time for novel MRI catheter tracking technology in patients undergoing template-based interstitial gynecologic brachytherapy implants. From 2018 to 2022, gynecologic patients undergoing template-based (Syed/Neblett) interstitial brachytherapy were included in this analysis. There are two cohorts: those treated with MRI-tracking technology and a comparison cohort. All patients underwent a standard template-based interstitial procedure, which included clinical examination, procedure preparation, obturator and needle insertion, mid-procedure MR images (if any), and final MRI acquisitions used in contouring and treatment planning. Additionally, for patients consenting to the MR-guided treatment investigation, custom-built MRI-tracking stylets were inserted in the implantable catheters to visualize positioning on the mid-procedure MR images as they were implanted. The procedural workflow is illustrated in Figure 1. For the investigational patient group, data logs recorded the procedure time dedicated to needle insertion. The comparison cohort of patients treated without MRI-tracking technology was used to determine the impact to procedure time when adding novel, developmental MRI-tracking technology. Extracted from the electronic medical record, the procedure start time was indicated by anesthesia handover to the attending radiation oncologist and procedure completion was indicated by the acquisition time of the post-implant MR imaging sequence. The procedure times and needle insertion times were reported as the median and interquartile range, which were compared using a student's t-test with alpha of 0.05 indicating significance. For both cohorts, patient and treatment characteristics are reported including primary disease site and average needles inserted. Between 2018 to 2022, 18 patients consented to interstitial procedures guided by MRI-tracking technology. For the same period, the comparison cohort without MRI-tracking technology included 62 patients. The disease sites for the MRI-tracking patients are eight cervix, seven vaginal, and three endometrial recurrences. The average needles inserted (± standard deviation) were 13 (± 4) and 14 (± 4) for the MRI-tracking and comparison cohorts (p = 0.49), respectively. Additionally, the median (interquartile range) procedure time was 95 (70 to 119) minutes and 99 (83 to 110) minutes for the MRI-tracking and non-MRI tracking patients, respectively. No statistical difference in procedure time is observed (p = 0.55). For patients with MRI-tracking, data logs times showed a median of 28 (23 to 43) minutes, which indicates the needle insertion is approximately one third of the total procedure time and approximately 2.2 minutes per needle. In the developmental stage of MRI-tracking technology, procedural times are not observed to be different from the standard procedures. Clinical implementation of developmental MRI-tracking stylets resulted in procedure time that did not show a difference when compared to standard procedures. This result suggests the additional overhead of incorporating developmental MRI-tracking technology in the procedure is offset by the physician's capability to more quickly complete the implant based on mid-procedure visualization of catheter implants. [ABSTRACT FROM AUTHOR]

Purpose: Chartrounds (www.chartrounds.com) was established in the United States in 2010 as a web-based platform for radiation oncologists to review cases with leading disease-site experts. However, the need for access to experts for peer review and education is not unique to the United States, and the Chartrounds platform was therefore adapted for improved global reach. Chartrounds was first expanded to India, and herein we report our initial experience with this initiative.Methods and Materials: The US Chartrounds platform was adapted to create Chartrounds India (ind.chartrounds.com). Through collaboration with the Association of Radiation Oncologists of India, India-based specialists were recruited, and the association's membership list was used to announce sessions to potential participants.Results: Between June 2017 and January 2018, 27 Chartrounds India sessions were completed, led by 21 different specialists (representing 10 centers in India) and covering 11 different disease sites/topics. A total of 240 members from 126 centers (private: 56%; teaching: 36%; public: 8%) across 24 states/territories participated in ≥1 session. Of the 240 members who participated in ≥1 session, 159 (66%) participated in ≥2 sessions and 60 (25%) participated in ≥5 sessions. The average number of participants per session was 34 (range, 13-72). On average, 80% of respondents rated the sessions as high or very high quality; 87% and 95% agreed or strongly agreed that the time was used effectively and that the sessions were relevant to daily practice, respectively. Seventy-six percent agreed or strongly agreed that the sessions will result in a change in their practice. The average feedback survey response rate was 32% (range, 17%-49%).Conclusions: Chartrounds has proven to be an effective resource for US-based radiation oncologists, and our initial experience with Chartrounds India suggests that an online platform for radiation oncology case review and education can be successfully implemented globally with use of local disease site experts. [ABSTRACT FROM AUTHOR]

Purpose To compare clinical outcomes of MR-based versus CT-based high-dose-rate interstitial brachytherapy (ISBT) for vaginal recurrence of endometrioid endometrial cancer (EC). Methods and Materials We reviewed 66 patients with vaginal recurrent EC; 18 had MR-based ISBT on a prospective clinical trial and 48 had CT-based treatment. Kaplan–Meier survival modeling was used to generate estimates for local control (LC), disease-free interval (DFI), and overall survival (OS), and multivariate Cox modeling was used to assess prognostic factors. Toxicities were evaluated and compared. Results Median followup was 33 months (CT 30 months, MR 35 months). Median cumulative equivalent dose in 2-Gy fractions was 75.5 Gy for MR-ISBT and 73.8 Gy for CT-ISBT ( p = 0.58). MR patients were older ( p = 0.03) and had larger tumor size (>4 cm vs. ≤ 4 cm) compared to CT patients ( p = 0.04). For MR-based versus CT-based ISBT, 3-year KM rate for local control was 100% versus 78% ( p = 0.04), DFI was 69% versus 55% ( p = 0.1), and OS was 63% versus 75% ( p = 0.81), respectively. On multivariate analysis, tumor Grade 3 was associated with worse OS (HR 3.57, 95% CI 1.25, 11.36) in a model with MR-ISBT (HR 0.56, 95% CI 0.16, 1.89). Toxicities were not significantly different between the two modalities. Conclusion Despite worse patient prognostic features, MR-ISBT was associated with a significantly better (100%) 3-year local control, comparable survival, and improved DFI rates compared to CT. Toxicities did not differ compared to CT-ISBT patients. Tumor grade contributed as the most significant predictor for survival. Larger prospective studies are needed to assess the impact of MR-ISBT on survival outcomes. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To present recommendations for the use of interstitial brachytherapy in patients with vaginal cancer or recurrent endometrial cancer in the vagina. Methods: A panel of members of the American Brachytherapy Society reviewed the literature, supplemented that with their clinical experience, and formulated recommendations for interstitial brachytherapy for primary or recurrent cancers in the vagina. Results: Patients with bulky disease (approximately >0.5cm thick) should be considered for treatment with interstitial brachytherapy. The American Brachytherapy Society reports specific recommendations for techniques, target volume definition, and dose–fractionation schemes. Three-dimensional treatment planning is recommended with CT scan and/or MRI. The treatment plan should be optimized to conform to the clinical target volume and should reduce the dose to critical organs, including the rectum, bladder, urethra, and sigmoid colon. Suggested doses in combination with external beam radiation therapy and summated equivalent doses in 2Gy fractions are tabulated. Conclusion: Recommendations are made for interstitial brachytherapy for vaginal cancer and recurrent disease in the vagina. Practitioners and cooperative groups are encouraged to use these recommendations to formulate treatment and dose-reporting policies. Such a process will result in meaningful outcome comparisons, promote technical advances, and lead to appropriate utilization of these techniques. [Copyright &y& Elsevier]