Search

Background: Electromagnetic Tracking (EMT) technology has been integrated in a prototype high-dose-rate brachytherapy (HDR-BT) afterloading device. Its potential for dwell position (DP) monitoring has earlier been demonstrated in prostate phantoms. However, its performance for prostate BT in the clinical setting remains to be assessed., Aim: Assess the reliability and value of EMT measurements in transrectal ultrasound-based (TRUS-based) and computed tomography-based (CT-based) prostate HDR-BT., Methods: EMT measurements were conducted on 20 patients undergoing dual-fraction prostate HDR-BT monotherapy. In each treatment fraction an individual TRUS-based or CT-based treatment plan was generated. The measurements were compared to DPs of manually reconstructed needles in those TRUS-based or CT-based treatment plans. An internal reference sensor was also placed in one needle to assess internal movement levels and its potential for movement correction., Results: For TRUS-based treatments, median Euclidean distances (ED) of 1.00 mm were observed between EMT measurements and manual DP determination. Reference sensor movement was minimal at a median of 0.18 mm. For DPs measured in the CT-room and treatment room, median EDs of 1.60 mm and 2.24 mm compared to CT-based DP determination respectively were observed, indicating the system's ability to detect changes in implant geometry over time and after patient repositioning. Median reference sensor movement of 0.97 mm was observed. Implementing reference sensor-based movement correction led to a significant but small decrease in ED for CT-based treatments., Conclusion: EMT is suitable for TRUS-based prostate HDR-BT quality assurance and error detection. While EMT can identify changes in implant geometry in CT-based prostate HDR-BT treatments, it showed lower accuracy in this setting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Purpose: The molecular classification of endometrial cancer (EC) has proven to have prognostic value and is predictive of response to adjuvant chemotherapy. Here, we investigate its predictive value for response to external beam radiotherapy (EBRT) and vaginal brachytherapy (VBT) in early-stage endometrioid EC (EEC)., Methods: Data of the randomized PORTEC-1 trial (n = 714) comparing pelvic EBRT with no adjuvant therapy in early-stage intermediate-risk EC and the PORTEC-2 trial (n = 427) comparing VBT with EBRT in early-stage high-intermediate-risk EC were used. Locoregional (including vaginal and pelvic) recurrence-free survival was compared between treatment groups across the four molecular classes using Kaplan-Meier's methodology and log-rank tests., Results: A total of 880 molecularly classified ECs, 484 from PORTEC-1 and 396 from PORTEC-2, were included. The majority were FIGO-2009 stage I EEC (97.2%). The median follow-up was 11.3 years. No locoregional recurrences were observed in EC with a pathogenic mutation of DNA polymerase-ε ( POLE mut EC). In mismatch repair-deficient (MMRd) EC, locoregional recurrence-free survival was similar after EBRT (94.2%), VBT (94.2%), and no adjuvant therapy (90.3%; P = .74). In EC with a p53 abnormality (p53abn EC), EBRT (96.9%) had a substantial benefit over VBT (64.3%) and no adjuvant therapy (72.2%; P = .048). In EC with no specific molecular profile (NSMP EC), both EBRT (98.3%) and VBT (96.2%) yielded better locoregional control than no adjuvant therapy (87.7%; P < .0001)., Conclusion: The molecular classification of EC predicts response to radiotherapy in stage I EEC and may guide adjuvant treatment decisions. Omitting radiotherapy seems to be safe in POLE mut EC. The benefit of radiotherapy seems to be limited in MMRd EC. EBRT yields a significantly better locoregional recurrence-free survival than VBT or no adjuvant therapy in p53abn EC. VBT is the treatment of choice for NSMP EC as it is as effective as EBRT and significantly better than no adjuvant therapy for locoregional tumor control.

Background and Purpose: Image-guided adaptive brachytherapy (IGABT) is an important modality in the cervical cancer treatment, and plan quality is sensitive to time pressure in the workflow. Patient anatomy-based quality-assurance (QA) with overlap volume histograms (OVHs) has been demonstrated to detect suboptimal plans (outliers). This analysis quantifies the possible improvement of plans detected as outliers, and investigates its suitability as a clinical QA tool in a multi-center setting., Materials and Methods: In previous work OVH-based models were investigated for the use of QA. In this work a total of 160 plans of 68 patients treated in accordance with the current state-of-the-art IGABT protocol from Erasmus MC (EMC) were analyzed, with a model based on 120 plans (60 patients) from UMC Utrecht (UMCU). Machine-learning models were trained to define QA thresholds, and to predict dose D 2cm3 to bladder, rectum, sigmoid and small bowel with the help of OVHs of the EMC cohort. Plans out of set thresholds (outliers) were investigated and retrospectively replanned based on predicted D 2cm3 values., Results: Analysis of replanned plans demonstrated a median improvement of 0.62 Gy for all Organs At Risk (OARs) combined and an improvement for 96 % of all replanned plans. Outlier status was resolved for 36 % of the replanned plans. The majority of the plans that could not be replanned were reported having implantation complications or insufficient coverage due to tumor geometry., Conclusion: OVH-based QA models can detect suboptimal plans, including both unproblematic BT applications and suboptimal planning circumstances in general. OVH-based QA models demonstrate potential for clinical use in terms of performance and user-friendliness, and could be used for knowledge transfer between institutes. Further research is necessary to differentiate between (sub)optimal planning circumstances., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background and Purpose: Image-guided adaptive brachytherapy (IGABT) is a key component in the treatment of cervical cancer, but the nature of the clinical workflow makes it vulnerable to suboptimal plans, as the theoretical optimal plan depends heavily on organ configuration. Patient anatomy-based quality-assurance (QA) with overlap volume histograms (OVHs) is a promising tool to detect such suboptimal plans, and in this analysis its suitability as a multi-institutional clinical QA tool is investigated., Materials and Methods: A total of 223 plans of 145 patients treated in accordance with the current state-of-the-art IGABT protocols from UMC Utrecht (UMCU) and Erasmus MC (EMC) were included. Machine-learning models were trained to predict dose D 2cm3 to bladder, rectum, sigmoid and small bowel with the help of OVHs. For this strategy, points are sampled on the organs-at-risk (OARs), and the distances of the sampled points to the target are computed and combined in a histogram. Machine-learning models can then be trained to predict dose-volume histograms (DVHs) for unseen data. Single-center model robustness to needle use and applicator type and multi-center model translatability were investigated. Performance of models was assessed by the difference between planned (clinical) and predicted D 2cm3 values., Results: Intra-validation of UMCU data demonstrated OVH model robustness to needle use and applicator type. The model trained on UMCU data was found to be robust within the same protocol on EMC data, for all investigated OARs. Mean squared error between planned and predicted D 2cm3 values of OARs ranged between 0.13 and 0.40 Gy within the same protocol, indicating model translatability. For the former protocol cohort of Erasmus MC large deviations were found between the planned and predicted D 2cm3 values, indicating plan deviation from protocol. Mean squared error for this cohort ranged from 0.84 to 4.71 Gy., Conclusion: OVH-based models can provide a solid basis for multi-institutional QA when trained on a sufficiently strict protocol. Further research will quantify the model's impact as a QA tool., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Brachytherapy is a common treatment in cervical, uterine and vaginal cancer management. The technique is characterised by rapid developments in the fields of medical imaging, dosimetry planning and personalised medical device design. To reduce unnecessary burden on patients, assessments and training of these technologies should preferable be done using high-fidelity physical phantoms. In this study, anthropomorphic deformable phantoms of the vaginal wall and cavity were developed for image-guided adaptive brachytherapy, in which vaginal wall biomechanics were mimicked. Phantoms were produced from both silicone and polyvinyl alcohol materials. Material characterisations were performed with uniaxial tensile tests, via which Young's moduli and toughness were quantified. In addition, the contrast between adjacent phantom layers was quantified in magnetic resonance images. The results showed that stress-strain curves of the silicone phantoms were within the range of those found in healthy human vaginal wall tissues. Sample preconditioning had a large effect on Young's moduli, which ranged between 2.13 and 6.94 MPa in silicone. Toughness was a more robust and accurate metric for biomechanical matching, and ranged between 0.23 and 0.28 ·10 6 J·m -3 as a result of preconditioning. The polyvinyl alcohol phantoms were not stiff or tough enough, with a Young's modulus of 0.16 MPa and toughness of 0.02 ·10 6 J·m -3 . All materials used could be clearly delineated in magnetic resonance images, although the MRI sequence did affect layer contrast. In conclusion, we developed anthropomorphic deformable phantoms that mimic vaginal wall tissue and are well visible in magnetic resonance images. These phantoms will be used to evaluate the properties and to optimise the development and use of personalised brachytherapy applicators., (Creative Commons Attribution license.)

Background and Purpose: To investigate the accuracy of dwell position detection with a combined electromagnetic tracking (EMT) brachytherapy (BT) system for treatment verification, by quantifying positional errors due to EM field interference in typical pelvic BT clinical settings., Materials and Methods: Dedicated prostate and cervix BT phantoms were imaged with CT. For the cervix phantom, the Utrecht applicator + interstitial catheters were used. The implants were reconstructed and treatment plans were created with 270/65 dwell positions for the prostate/cervix phantom. Next, EMT experiments were performed in clinical BT settings using a prototype of a combined EMT/BT system. We quantified positional errors due to EM field interference from surrounding equipment by comparing planned and EMT-measured dwell positions. The mean residual error between planned and EMT-measured dwell positions was calculated in the prostate interstitial catheters and in the whole cervix implant including the applicator. For the cervix phantom, the analysis was repeated for only the interstitial catheters., Results: Mean residual errors of less than 0.5/0.4 mm in the prostate/cervix catheters were found. For the whole cervix implant including the applicator, large deviations up to 2.4 mm were found. Compared to the interference free set-up, the CT and patient bed environments showed larger residual errors in the interstitial catheters, but residual errors remained <1 mm in all cases., Conclusion: Dwell position detection with the combined system in interstitial catheters is sufficiently accurate to perform EMT-based treatment verification. The effect of EM interference from the surrounding equipment was limited., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: To develop and evaluate a fast, automated multi-criterial treatment planning approach for adaptive high-dose-rate (HDR) intracavitary + interstitial brachytherapy (BT) for locally advanced cervical cancer., Methods and Materials: Twenty-two previously delivered single fraction MRI-based HDR treatment plans (SF clin ) were used to guide training of our in-house system for multi-criterial autoplanning, aiming for an autoplan quality superior to the training plans, while respecting the clinically desired "pear-shaped" dose distribution. Next, the configured algorithm was used to automatically generate treatment plans for 63 other fractions (SF auto ). The SF auto plans were compared to the corresponding SF clin plans in blind pairwise comparisons by an expert clinician. Then, the effect of adaptive autoplanning on total treatment (TT) plans (external beam + 3 BT fractions) was evaluated for 16 patients by simulating the clinically applied adaptive strategy to generate TT auto plans and compare them with the corresponding clinical treatments (TT clin )., Results: In the blind comparisons, all SF auto plans were considered clinically acceptable. In 62/63 comparisons, SF auto plans were considered at least as good as, or better than the corresponding SF clin . The average optimization time for autoplanning was 20.5 ± 19.2 s (range 4.4-106.4 s) per plan. In 14 of 16 TT auto plans, the desired total dose of 90 Gy (EQD 2 ) was obtained, compared to only 9 in the corresponding TT clin , while autoplanning also decreased bladder and rectum doses., Conclusions: Fast, fully-automated multi-criterial treatment planning for adaptive HDR-BT for locally advanced cervical cancer is feasible. Autoplans were superior to corresponding clinical plans., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Addition of deep hyperthermia results in improved local control (LC) and overall survival (OS) compared to radiotherapy alone in patients with cervical carcinoma. Previously, we showed that the thermal dose of hyperthermia significantly correlates with LC and disease specific survival (DSS). Over the last decade, new radiation techniques were introduced resulting in improved LC., Aim: To validate the effect of thermal dose in a more recent cohort of patients treated with modern radiotherapy techniques, including image guided brachytherapy (IGBT)., Methods: We analyzed primary cervical carcinoma patients treated with a combination of radiotherapy and deep hyperthermia between 2005 and 2016 at our institute. Data on patient, tumor and treatment were collected including the thermal dose parameters TRISE and CEM43T90. Follow-up data on LC, disease free survival, DSS, OS as well as late toxicity data were collected. Data were analyzed using the Cox proportional hazard and Kaplan-Meier analyses., Results: 227 patients were included. In multivariate analysis, histology, FIGO stage, lymphadenopathy, TRISE, CEM43T90 and IGBT had a significant effect on LC. In the patients treated with IGBT, the thermal dose parameter TRISE remained to have a significant effect on LC in univariate analysis., Conclusions: The positive association between thermal dose and clinical outcome is replicated in an independent, recent cohort of cervical carcinoma patients. Importantly, in patients receiving IGBT, the effect of thermal dose on clinical outcome is still observed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Introduction: Treatment with pelvic external beam radiotherapy with brachytherapy (EBRT/BT) for gynecological cancers may cause sexual dysfunction because of vaginal shortening and tightening. Regular vaginal dilator use is thought to reduce vaginal shortening and/or tightening, but compliance is poor., Aims: This study identified determinants of patients' adherence with dilator use after EBRT/BT., Methods: Semi-structured interviews were conducted with 30 women, aged 32-67 years, treated with EBRT/BT for gynecological cancers at two university medical centers in the past 36 months. Transcriptions were coded and analyzed with N-Vivo software., Main Outcome Measures: Determinants of dilator use were clustered based on the Health Action Process Approach, which describes (i) motivation processes that lead to a behavioral intention and (ii) volition processes that lead to the initiation or maintenance of actual behavior., Results: Almost all women attempted to perform long-term regular vaginal dilator use. Intended dilator use was determined by the expectation that it would prevent the development of vaginal adhesions and stenosis. Planning dilator use and making it part of a routine, using it under the shower, using lubricants, a smaller dilator size, or vibrators helped women. Others reported a lack of time or privacy, forgetting, or feeling tired. Women self-regulated dilator use by rotating the dilator and timing dilator use. Influencing factors were negative emotions regarding dilator use or its hard plastic design, (being anxious for) pain or blood loss, and an association with EBRT/BT. Some women mentioned a lack of instrumental support, for example, lubricants. Others received reassurance through informational support or were supported socially., Conclusion: Motivation and volition processes that determined dilator use were identified and used in the development of a sexual rehabilitation intervention. It is important to provide sufficient patient information and support, and enlarge patients' perceived self-efficacy., (© 2014 International Society for Sexual Medicine.)

A novel model of the titanium Rotterdam tandem and ovoid applicator is presented. As titanium produces artefacts in MR images, an MR sequence was sought and optimised for visualisation and accurate applicator reconstruction. The mean inter-observer (8 observers) variability for four patients was only 0.7 mm (maximum 1.7 mm)., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Abstract: Background: The PORTEC-2 trial showed efficacy and reduced side-effects of vaginal brachytherapy (VBT) compared with external beam pelvic radiotherapy (EBRT) for patients with high-intermediate risk endometrial cancer. The current analysis was done to evaluate long-term health related quality of life (HRQL), and compare HRQL of patients to an age-matched norm population. Methods: Patients were randomly allocated to EBRT (n =214) or VBT (n =213). HRQL was assessed using EORTC QLQ-C30 and subscales from PR25 and OV28 (bladder, bowel, sexual symptoms); and compared to norm data. Findings: Median follow-up was 65 months; 348 (81%) patients were evaluable for HRQL (EBRT n =166, VBT n =182). At baseline, patient functioning was at lowest level, increasing during and after radiotherapy to reach a plateau after 12 months, within range of scores of the norm population. VBT patients reported better social functioning (p =0.005) and lower symptom scores for diarrhoea, faecal leakage, need to stay close to a toilet and limitation in daily activities due to bowel symptoms (p ⩽0.001), compared to EBRT. There were no differences in sexual functioning or symptoms between the treatment groups; however, sexual functioning was lower and sexual symptoms more frequent in both treatment groups compared to the norm population. Interpretation: Patients who received EBRT reported clinically relevant higher levels of bowel symptoms and related limitations in daily activities with lower social functioning, 5 years after treatment. VBT provides a better HRQL, which remained similar to that of an age-matched norm population, except for sexual symptoms which were more frequent in both treatment groups. [Copyright &y& Elsevier]