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Introduction Methods Results Conclusion Paediatric cancers are rare, and most children requiring radiation therapy receive external beam radiation (EBRT). Although EBRT may offer organ preservation compared to surgery, it can be associated with significant late effects. Image‐guided brachytherapy is a highly specialised technique offering both organ preservation and dose conformity to minimise late toxicity.This is a retrospective mono‐institutional review of paediatric brachytherapy in one of the largest paediatric centres in Australia. Outcomes and toxicities are presented as well as brachytherapy versus proton plan comparison in four patients.A total of 14 patients were treated with adjuvant brachytherapy between 2012 and 2022. The predominant histology was rhabdomyosarcoma, and all patients had pelvic tumours. High‐dose rate (HDR) brachytherapy was given for 13 patients with one patient receiving low‐dose rate (LDR) brachytherapy. Only one grade three late toxicity was reported and two patients developed metastatic disease within one year of completion of treatment. The brachytherapy plan was superior to protons in two of four patients and equivocal in one patient.This is the first Australian publication of a paediatric brachytherapy series from a single institution. This retrospective series demonstrates the feasibility and safety of brachytherapy in paediatric pelvic tumours. The initial work presented here demonstrates the value of a comprehensive radiation plan review in selecting the optimal modality for an individual paediatric patient. [ABSTRACT FROM AUTHOR]

This document is a compilation of various research studies and articles on prostate cancer, focusing on treatment approaches, patient characteristics, and outcomes. The studies cover countries such as Nigeria, Ghana, Burkina Faso, and Cameroon, and examine factors like marital status, socioeconomic status, and age in relation to prostate cancer. The document provides valuable information for researchers and healthcare professionals interested in understanding the diverse perspectives and experiences of prostate cancer patients in different regions. [Extracted from the article]

Purpose: Intraprostatic recurrence (IRR) of prostate cancer after radiation therapy is increasingly identified. Our objective was to review the literature to determine the optimal workup for identifying IRR, the management options, and practical considerations for the delivery of re-irradiation as salvage local therapy. Methods: We performed a systematic review of available publications and ongoing studies on the topics of IRR, with a focus on salvage re-irradiation. Results: Work up of biochemically recurrent prostate cancer includes PSMA PET/CT and multiparametric MRI, followed by biopsy to confirm IRR. Management options include continued surveillance, palliative hormonal therapy, and salvage local therapy. Salvage local therapy can be delivered using re-irradiation with low dose rate brachytherapy, high dose rate (HDR) brachytherapy, and stereotactic body radiotherapy (SBRT), as well as non-radiation modalities, such as cryotherapy, high-intensity focused ultrasound, irreversible electroporation and radical prostatectomy. Data demonstrate that HDR brachytherapy and SBRT have similar efficacy compared to the other salvage local therapy modalities, while having more favorable side effect profiles. Recommendations for radiation therapy planning and delivery using HDR and SBRT based on the available literature are discussed. Conclusion: Salvage re-irradiation is safe and effective and should be considered in patients with IRR. [ABSTRACT FROM AUTHOR]

Background: High‐dose‐rate (HDR) brachytherapy (BT) has been acknowledged as a widely utilized treatment for patients with intermediate‐ and high‐risk prostate cancer, despite its side effects such as edema, incontinence, and impotence. Nevertheless, the treatment is consistently limited by the potential danger of excessive irradiation to organs‐at‐risk (OARs) like the urethra, bladder, and rectum. Purpose: This study aims to introduce curvilinear catheter implantation in the prostate gland for HDR treatment. The objective is to improve the radiation dose distribution by offering access channels conformal to the prostate anatomy. This approach seeks to minimize toxicity to nearby OARs while utilizing a reduced number of needles, potentially leading to improved clinical outcomes. Methods: Curvilinear catheters were first pre‐planned for an anonymized patient using Oncentra treatment planning system (TPS) and hybrid inverse planning optimization (HIPO) algorithm. The trajectories of the catheters were then analyzed using MATLAB to extract their radius of curvature. Tendon‐driven active needles were then used to implant curvilinear catheters inside an anthropomorphic phantom. Results: Proposed curvilinear catheter implantation resulted in significant improvement in terms of dosimetric constraints to the OARs and coverage to the prostate. Tendon‐driven active needles were shown to be capable of realizing the required pre‐planned curvatures inside prostate. It was shown that the active needle can realize a desired radius of curvature and a desired trajectory with an average accuracy of 9.1 ± 8.6 and 1.27 ± 0.50 mm in air and inside a tissue‐mimicking phantom, respectively. Conclusion: This work demonstrates the feasibility of using tendon‐driven active curvilinear catheter implantation in prostate to improve the outcomes of HDR‐BT via improved radiation dose distribution to the prostate and reduced toxicity to the OARs. [ABSTRACT FROM AUTHOR]

Whether brachytherapy based microboosting of the dominant intraprostatic lesion (DIL) improves outcomes over standard approaches is not known. The purpose of this study is to perform a systematic review on brachytherapy microboosting of the DIL to evaluate clinical outcomes and toxicities with this treatment approach. This review was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Databases including Pubmed, Embase, and Google Scholar were queried. About 16 studies met our inclusion criteria. These studies reported PSA control and/or toxicities based on standardized scales. There were 10 studies (two monotherapy, eight combination) that used HDR microboosting on a total of 516 patients. HDR dose (EQD2 assuming alpha/beta of 1.5) to the DIL ranged from 90 to 180 Gy. Most patients were low/intermediate risk. PSA control rates at 5–8 years ranged from 69% to 100%. Acute/late G3-G4 GU/GI toxicities ranged from 0% to 12%. There were six studies (five monotherapy, one combination) that used LDR microboosting on a total of 1041 patients. Studies performed a microboost of 130–150% of the whole gland prescription to the DIL. Most patients were low/intermediate risk. PSA control rates at 5 years ranged from 69% to 98%. Acute/late G3–4 GU/GI toxicities ranged from 0% to 4%. Over 1000 patients have been treated with a brachytherapy based microboost in published series. Severe acute/late toxicities appear limited. PSA control rates with more than 5 years of follow-up are limited. Longer-term follow-up is needed to determine ideal utilization of this approach. [ABSTRACT FROM AUTHOR]

In vivo dosimetry (IVD) is rarely performed in brachytherapy (BT), allowing potential dose misadministration to go unnoticed. This study presents a clinical routine-calibration method of detectors for IVD in high (HDR) and pulsed dose rate (PDR) Ir-192 BT. To evaluate the dosimetric precision and feasibility of an in-clinic calibration routine of detectors for IVD in afterloading BT. Calibrations were performed in a PMMA phantom with two needles inserted 20 mm apart. The source was loaded in one of the needles at 15 dwells for 10 s. The detector was placed in the other needle, and its signal was recorded. The mean signal at each dwell position was fitted to the expected dose rate with the calibration factor and the detector's longitudinal position being free parameters. The method was tested with an inorganic scintillation detector using one Ir-192 FlexiSource HDR and two Ir-192 GammaMedPlus PDR sources and followed by validation measurements in water. The standard measurement uncertainty (k = 1) of the calibration factor in absolute terms (Gy/s) was 3.2/3.4% for the HDR/PDR source. The uncertainty was dominated by source strength uncertainty, and the precision of the method was <1%. The mean ± 1SD of the difference in measured and expected dose rate during validation was 1.5 ± 4.7% (HDR) and 0.0 ± 4.1% (PDR) with a positional uncertainty in the setup of 0.33/0.23 mm (HDR/PDR) (k = 1). A precise and feasible in-clinic calibration method for IVD and source strength consistency tests in BT was presented. [ABSTRACT FROM AUTHOR]

We aim to investigate perioperative and subacute postoperative complications in patients undergoing LDR or HDR monotherapy for prostate cancer. We hypothesize a low rate of complications, and a favorable toxicity profile in patients treated with HDR compared to LDR. A prospectively collected institutional database was queried for patients treated with HDR or LDR prostate monotherapy between 1998 and 2021. Toxicities were determined per CTCAE. Claims based billing codes were obtained to identify additional events. Events occurring within 4 months of treatment were defined as perioperative or subacute postoperative complications. 759 patients were identified, 446 received LDR with 125I, and 313 received HDR with 192Ir. HDR patients had higher risk features: 75.7% with Gleason score 7+ versus 2.4% of LDR, and 16% with initial PSA 10+ ng/mL versus 2.7% of LDR. Toxicities were mild with the most common being grade 1 GU frequency and nocturia at ∼50%. HDR patients had significantly less grade 2 dysuria (2.6% vs. 9.0%), frequency (4.8% vs. 9.4%), hematuria (1.0% vs. 5.2%), nocturia (3.8% vs. 9.4%), and urinary obstructive symptoms (7.3% vs. 11.2%), all statistically significant. 11 (1.4%) patients had infection requiring antibiotics: 8 (1.8%) from the LDR group and 3 (1%) from the HDR group. Cardiopulmonary events were low at <2% overall, without difference between HDR and LDR. Overall toxicity rates support the safety of prostate brachytherapy. HDR monotherapy is associated with significantly less perioperative and subacute postoperative GU events when compared to LDR monotherapy. Cardiopulmonary events were equally rare in both groups. [ABSTRACT FROM AUTHOR]

This study compares conventional 192Ir-based high dose rate brachytherapy (HDR-BT) with 169Yb-based HDR intensity modulated brachytherapy (IMBT) for focal prostate cancer treatment. Additionally, the study explores the potential to generate less invasive treatment plans with IMBT by reducing the number of catheters needed to achieve acceptable outcomes. A retrospective dosimetric study of ten prostate cancer patients initially treated with conventional 192Ir-based HDR-BT and 5-14 catheters was employed. RapidBrachyMCTPS, a Monte Carlo-based treatment planning system was used to calculate and optimize dose distributions. For 169Yb-based HDR IMBT, a custom 169Yb source combined with 0.8 mm thick platinum shields placed inside 6F catheters was used. Furthermore, dose distributions were investigated when iteratively removing catheters for less invasive treatments. With IMBT, the urethra D 10 and D 0.1cc decreased on average by 15.89 and 15.65 percentage points (pp) and the rectum V 75 and D 2cc by 1.53 and 11.54 pp, respectively, compared to the conventional clinical plans. Similar trends were observed when the number of catheters decreased. On average, there was an observed increase in PTV V 150 from 2.84 pp with IMBT when utilizing all catheters to 8.83 pp when four catheters were removed. PTV V 200 increased from 0.42 to 2.96 pp on average. Hotspots in the body were however lower with IMBT compared to conventional clinical plans. 169Yb-based HDR IMBT for focal treatment of prostate cancer has the potential to successfully deliver clinically acceptable, less invasive treatment with reduced dose to organs at risk. [ABSTRACT FROM AUTHOR]

High dose-rate (HDR) brachytherapy is integral for the treatment of numerous cancers. Preclinical studies involving HDR brachytherapy are limited. We aimed to describe a novel platform allowing multi-modality studies with clinical HDR brachytherapy and external beam irradiators, establish baseline dosimetry standard of a preclinical orthovoltage irradiator, to determine accurate dosimetric methods. A dosimetric assessment of a commercial preclinical irradiator was performed establishing the baseline dosimetry goals for clinical irradiators. A 3D printed platform was then constructed with 14 brachytherapy channels at 1cm spacing to accommodate a standard tissue culture plate at a source-to-cell distance (SCD) of 1 cm or 0.4 cm. 4-Gy CT-based treatment plans were created in clinical treatment planning software and delivered to 96-well tissue culture plates using an Ir192 source or a clinical linear accelerator. Standard calculation models for HDR brachytherapy and external beam were compared to corresponding deterministic model-based dose calculation algorithms (MBDCAs). Agreement between predicted and measured dose was assessed with 2D-gamma passing rates to determine the best planning methodology. Mean (±standard deviation) and median dose measured across the plate for the preclinical irradiator was 423.7 ± 8.5 cGy and 430.0 cGy. Mean percentage differences between standard and MBDCA dose calculations were 9.4% (HDR, 1 cm SCD), 0.43% (HDR, 0.4 cm SCD), and 2.4% (EBRT). Predicted and measured dose agreement was highest for MBDCAs for all modalities. A 3D-printed tissue culture platform can be used for multi-modality irradiation studies with great accuracy. This tool will facilitate preclinical studies to reveal biologic differences between clinically relevant radiation modalities. [ABSTRACT FROM AUTHOR]

Kilovoltage computed tomography plays a crucial role in radiotherapy planning. However, the presence of high-density metallic objects can introduce streaking artifacts in CT scans, resulting in inaccurate dose calculations by the treatment planning software. Previous studies have explored manual density overrides and artifact reduction algorithms individually to enhance dose calculation accuracy, but their combined application on patient plans within a treatment planning system remains unexplored. This research aims to assess the necessity of manual density overrides when an artifact reduction algorithm is already employed to address dental artifacts in oropharyngeal cancer treatment plans. A total of 20 previously treated volumetric modulated arc therapy plans were collected, and manual density overrides were removed followed by plan recalculation. Dosimetric parameters were then compared between the original and modified plans. Statistical analysis revealed several dosimetric parameters for the planning target volume (PTV), clinical target volume (CTV), and oral cavity that exhibited statistically significant differences upon removing the manual density override. However, these differences were found to be small in absolute terms. No other organs evaluated demonstrated statistically significant differences in dose. The most significant disparity observed was an 8.26 cGy increase in mean dose to the CTV, which represents only 0.12% of the prescription dose. Based on these findings, it can be concluded that manual density overrides are likely unnecessary when an artifact reduction algorithm is employed in oropharyngeal cancer cases. [ABSTRACT FROM AUTHOR]

High dose rate (HDR) brachytherapy procedures for cervical cancer require multiple applicator insertions for multiple (typically 5) fractions of a single plan, which carries a risk for variability in applicator position between fractions. Due to applicator displacement relative to patient anatomy, the dose to nearby organs-at-risk (OARs) may vary significantly from one fraction to the next. The purpose of this study was to evaluate the effect of changes in HDR tandem and ring (T&R) applicator position on doses to nearby OARs and to present a quick and simple method to estimate doses to OARs inter-fractionally without having to perform a re-plan. Ninety CT image sets for 20 patients, ages 44 to 86, undergoing T&R-based HDR for cervical cancer were used retrospectively for this study. Measures of applicator positional and angular changes relative to the bony anatomy were obtained using image fusion in MIM software, between the planning CT (plan CT) and the CT on the treatment day (CT-TX). Dosimetric data were determined, also using MIM software, using the original (first fraction) dose distribution applied to organs at risk (rectum and bladder), transferred via rigid registration from the plan CT to each CT-TX. Bladder and rectum contours were also transferred from each plan CT to each CT-TX and were tweaked manually to match anatomy on each CT-TX and examined visually for appropriateness. Differences in translation and rotation of the T&R applicator between the planning CT and subsequent individual fractions were recorded and plotted against dose differences between each fraction of treatment and the original (first) fraction. Absolute dose (D 2cc) and volume (V 50) differences vs positional shifts were calculated and plotted, and the Pearson Product-Moment correlation coefficient between dose parameters and measured positional shifts was determined. Average dosimetric differences between planned dose and subsequent fractional doses obtained through rigid registration were 1.48 ± 1.92 Gy, 14.91 ± 11.92 cm3, 0.56 ± 0.93 Gy, and 1.77 ± 2.18 cm3 for Bladder D 2cc , Bladder V 50 , Rectum D 2cc , and Rectum V 50 , respectively. Correlation between Bladder V 50 and sagittal plane rotation gave an r2 of 0.4, showing the most correlation of all parameters studied. Bladder dose and volume increased by a maximum of about 2.7 Gy and 50 cm3 overall for Bladder D 2cc and Bladder V 50 , respectively. Bladder V 50 was most sensitive to T&R applicator displacements. We have quantified the effects of applicator positional changes on dose changes for the bladder and rectum. Even large changes in applicator position between fractions did not result in significant changes in dose to these normal tissues, indicating that adaptive re-planning is not necessary. [ABSTRACT FROM AUTHOR]

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 (FDiffuse) 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 (FDense) imaging utilized single-echo Late-Gadolinium-Enhanced IR-UTE, acquired ∼ 15 min post-Gadavist injection. Resulting FDiffuse and FDense 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 FDiffuse and FDense SI within (i) each IDL contour and (ii) the remnant tumor were calculated. Post-BT FDiffuse and FDense SI were correlated with prescribed BT-dose. To determine the relationship between BT-dose and IR-UTE SI, the differences in the post-BT FDense across IDLs was determined using paired t-tests with Bonferroni correction. Results: FDense 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. FDense 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 FDense post-BT (n = 5, r =.89, p =.04). Post-BT FDiffuse inversely correlated (n = 7, r = -.83, p =.02) with prescribed BT-dose within the 100% IDL. Conclusions: Results suggest that FDense SI 3–6 months post-BT is a sensitive measure of tissue response to heterogeneous BT radiation-dose. Future studies will validate whether FDiffuse and FDense are accurate biomarkers of fibrotic radiation response. [ABSTRACT FROM AUTHOR]

Background: Direction Modulated Brachytherapy (DMBT) enables conformal dose distributions. However, clinicians may face challenges in creating viable treatment plans within a fast‐paced clinical setting, especially for a novel technology like DMBT, where cumulative clinical experience is limited. Deep learning‐based dose prediction methods have emerged as effective tools for enhancing efficiency. Purpose: To develop a voxel‐wise dose prediction model using an attention‐gating mechanism and a 3D UNET for cervical cancer high‐dose‐rate (HDR) brachytherapy treatment planning with DMBT six‐groove tandems with ovoids or ring applicators. Methods: A multi‐institutional cohort of 122 retrospective clinical HDR brachytherapy plans treated to a prescription dose in the range of 4.8–7.0 Gy/fraction was used. A DMBT tandem model was constructed and incorporated onto a research version of BrachyVision Treatment Planning System (BV‐TPS) as a 3D solid model applicator and retrospectively re‐planned all cases by seasoned experts. Those plans were randomly divided into 64:16:20 as training, validating, and testing cohorts, respectively. Data augmentation was applied to the training and validation sets to increase the size by a factor of 4. An attention‐gated 3D UNET architecture model was developed to predict full 3D dose distributions based on high‐risk clinical target volume (CTVHR) and organs at risk (OARs) contour information. The model was trained using the mean absolute error loss function, Adam optimization algorithm, a learning rate of 0.001, 250 epochs, and a batch size of eight. In addition, a baseline UNET model was trained similarly for comparison. The model performance was evaluated on the testing dataset by analyzing the outcomes in terms of mean dose values and derived dose‐volume‐histogram indices from 3D dose distributions and comparing the generated dose distributions against the ground‐truth dose distributions using dose statistics and clinically meaningful dosimetric indices. Results: The proposed attention‐gated 3D UNET model showed competitive accuracy in predicting 3D dose distributions that closely resemble the ground‐truth dose distributions. The average values of the mean absolute errors were 1.82 ± 29.09 Gy (vs. 6.41 ± 20.16 Gy for a baseline UNET) in CTVHR, 0.89 ± 1.25 Gy (vs. 0.94 ± 3.96 Gy for a baseline UNET) in the bladder, 0.33 ± 0.67 Gy (vs. 0.53 ± 1.66 Gy for a baseline UNET) in the rectum, and 0.55 ± 1.57 Gy (vs. 0.76 ± 2.89 Gy for a baseline UNET) in the sigmoid. The results showed that the mean absolute error (MAE) for the bladder, rectum, and sigmoid were 0.22 ± 1.22 Gy (3.62%) (p = 0.015), 0.21 ± 1.06 Gy (2.20%) (p = 0.172), and ‐0.03 ± 0.54 Gy (1.13%) (p = 0.774), respectively. The MAE for D90, V100%, and V150% of the CTVHR were 0.46 ± 2.44 Gy (8.14%) (p = 0.018), 0.57 ± 11.25% (5.23%) (p = 0.283), and ‐0.43 ± 19.36% (4.62%) (p = 0.190), respectively. The proposed model needs less than 5 s to predict a full 3D dose distribution of 64 × 64 × 64 voxels for any new patient plan, thus making it sufficient for near real‐time applications and aiding with decision‐making in the clinic. Conclusions: Attention gated 3D‐UNET model demonstrated a capability in predicting voxel‐wise dose prediction, in comparison to 3D UNET, for DMBT intracavitary brachytherapy planning. The proposed model could be used to obtain dose distributions for near real‐time decision‐making before DMBT planning and quality assurance. This will guide future automated planning, making the workflow more efficient and clinically viable. [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance imaging (MRI) is the gold standard for delineating cancerous lesions in soft tissue. Catheter‐based interventions require the accurate placement of multiple long, flexible catheters at the target site. The manual segmentation of catheters in MR images is a challenging and time‐consuming task. There is a need for automated catheter segmentation to improve the efficiency of MR‐guided procedures. Purpose: To develop and assess a machine learning algorithm for the detection of multiple catheters in magnetic resonance images used during catheter‐based interventions. Methods: In this work, a 3D U‐Net was trained to retrospectively segment catheters in scans acquired during clinical MR‐guided high dose rate (HDR) prostate brachytherapy cases. To assess confidence in segmentation, multiple AI models were trained. On clinical test cases, average segmentation results were used to plan the brachytherapy delivery. Dosimetric parameters were compared to the original clinical plan. Data was obtained from 35 patients who underwent HDR prostate brachytherapy for focal disease with a total of 214 image volumes. 185 image volumes from 30 patients were used for training using a five‐fold cross validation split to divide the data for training and validation. To generate confidence measures of segmentation accuracy, five trained models were generated. The remaining five patients (29 volumes) were used to test the performance of the trained model by comparison to manual segmentations of three independent observers and assessment of dosimetric impact on the final clinical brachytherapy plans. Results: The network successfully identified 95% of catheters in the test set at a rate of 0.89 s per volume. The multi‐model method identified the small number of cases where AI segmentation of individual catheters was poor, flagging the need for user input. AI‐based segmentation performed as well as segmentations by independent observers. Plan dosimetry using AI‐segmented catheters was comparable to the original plan. Conclusion: The vast majority of catheters were accurately identified by AI segmentation, with minimal impact on plan outcomes. The use of multiple AI models provided confidence in the segmentation accuracy and identified catheter segmentations that required further manual assessment. Real‐time AI catheter segmentation can be used during MR‐guided insertions to assess deflections and for rapid planning of prostate brachytherapy. [ABSTRACT FROM AUTHOR]

Background: High dose rate (HDR) image-guided brachytherapy with Cobalt-60 isotope is a relatively recent approach. The aim of the study is to evaluate the clinical and dosimetric parameters in terms of tumour response, bladder, and rectal toxicity in patients undergoing Co-60 HDR brachytherapy. Materials and Method: All patients were initially treated with chemoradiation (CT-RT) at our center or other referral centers with external beam radiation therapy (EBRT) for a dose of 45 Gy–60 Gy at 1.8-2Gy/fraction (including nodal boost) with concomitant chemotherapy with either cisplatin or carboplatin. Patients were then scheduled for brachytherapy within 1 week after completion of CT-RT and are assessed by local examination. Depending on local examination parameters at the time of brachytherapy they were eligible either for intracavitary brachytherapy (ICBT) or interstitial brachytherapy (ISBT). Results: The complete response (CR) observed in stage I, II, III, IVA were 60%, 79.4%, 86% and 76.2% respectively. Complete response was seen in patients with mean EQD2 of 78.67 Gy10, 83.33 Gy10, 84.23 Gy10, 85.63 Gy10 in stages I, II, III, IVA respectively. 79.2% of cisplatin-treated patients and 87.5% of carboplatin-treated patients had a complete response indicating that patients treated with either chemotherapy had similar response rates. Conclusions: According to results obtained from the study we conclude by saying that higher rates of complete response to treatment in cervical cancer is seen in patients with shorter overall treatment time (OTT), shorter interval between end of definitive CT-RT and beginning of brachytherapy and squamous cell histology. The study also noted the trend of increasing mean EQD2 to tumor with increasing stage for achieving complete response. Higher acute bladder and rectal toxicity is seen in patients who received EQD2 of ¿70-90Gy3 and ¿70Gy3 respectively. The study findings suggest that the clinical outcomes and the toxicities are clinically comparable with other radioisotope based HDR brachytherapy treatment. [ABSTRACT FROM AUTHOR]

Objective Rectal toxicity is one of the primary dose-limiting side effects of prostate cancer radiotherapy, and consequential impairment on quality of life in these patients with long survival is an important problem. In this study, we aimed to evaluate the possibility of predicting rectal toxicity with artificial intelligence model which was including certain dosimetric parameters. Materials and methods One hundred and thirty-seven patients with a diagnosis of prostate cancer who received curative radiotherapy for prostate +/− pelvic lymphatics were included in the study. The association of the clinical data and dosimetric data between early and late rectal toxicity reported during follow-up was evaluated. The sample size was increased to 274 patients by synthetic data generation method. To determine suitable models, 15 models were studied with machine learning algorithms using Python 2.3, Pycaret library. Random forest classifier was used with to detect active variables. Results The area under the curve and accuracy were found to be 0.89–0.97 and 95%–99%, respectively, with machine learning algorithms. The sensitivity values for acute and toxicity were found to be 0.95 and 0.99, respectively. Conclusion Early or late rectal toxicity can be predicted with a high probability via dosimetric and physical data and machine learning algorithms of patients who underwent prostate +/− pelvic radiotherapy. The fact that rectal toxicity can be predicted before treatment, which may result in limiting the dose and duration of treatment, makes us think that artificial intelligence can enter our daily practice in a short time in this sense. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to validate the use of a model‐based dose calculation algorithm (MBDCA), Acuros BV, for high dose rate brachytherapy treatment planning for a community‐based hospital with a Bravos afterloader. Based on published AAPM recommendations, this work details a practical approach for community‐based clinics to complete initial validation of Acuros BV, in order to add a MBDCA to a TG‐43 based brachytherapy treatment planning program. Methods: Source dimensions and materials used in Acuros BV and TG‐43 source models were compared to the physical source. TG‐186 testing was completed with standardized test cases externally calculated with Monte Carlo compared to locally calculated with Acuros BV. Point doses calculated using TG‐43 were compared to those calculated with Acuros BV in water at various dose grid settings. Secondary dose check software was used to evaluate dose distributions resembling clinical patient plans, both in water and on CT datasets representative of patient anatomy. Results: The major source of discrepancy of source models was the length of modeled steel cable. TG‐186 testing showed that the largest differences between Monte Carlo and Acuros BV dose distributions were located along the source axis for cases calculated in water, as well as located in regions of high dose gradients and within the applicator for the case calculated with a generic shielded applicator. An audit of point doses calculated with both TG‐43 and Acuros BV in water found that dose grid settings significantly affected agreement. Secondary dose check software indicated that Acuros BV functioned satisfactorily, and a 5% threshold was adopted for secondary dose checks on gynecologic plans. Conclusion: This validation process indicated that Acuros BV met expected standards and affirmed its suitability for integration into this clinical practice's brachytherapy treatment planning. [ABSTRACT FROM AUTHOR]

Background: The management of locally recurrent gynecological carcinoma remains a challenge due to the limited availability of data. This study aims to share our institutional experience in using definitive radiotherapy (RT) for the treatment of locally recurrent cervical and endometrial carcinoma. Methods: The study retrospectively reviewed 20 patients in our hospital completing salvage 3D image-based HDR brachytherapy, with or without EBRT, for locally recurrent cervical and endometrial carcinoma after surgery. The Kaplan–Meier method was applied to estimate the disease-free survival (DFS) and overall survival (OS). The toxicities were assessed by CTCAEv5. Results: During a median observation period of 21 months, the study reported a tumor objective response rate of 95%. The 3-year DFS and OS rates were 89.4% and 90.9%, respectively. The EBRT combined with brachytherapy achieved a median cumulative dose of 88 Gy to CTV D90. 14 patients received concurrent and/or systemic chemotherapy. Two patients suffered locoregional recurrence after salvage treatment, one of whom only received salvage brachytherapy for prior RT history. The analysis identified significant predictors for DFS, including tumor histology and FIGO stage. 5 patients observed acute grade 1–2 rectal (15%) or genitourinary (10%) toxicities. Late toxicities including grade 1–2 rectal bleeding (10%) and grade 2 pelvic fracture (5%) were seen in 3 patients. Conclusions: 3D image-guided brachytherapy combined with EBRT shows effective tumor control and acceptable toxicity profile for women with locally recurrent gynecologic cancer. The success in managing vaginal recurrence is notably influenced by histologic subtype and FIGO staging. [ABSTRACT FROM AUTHOR]

Background: There currently exists no widespread high dose‐rate (HDR) brachytherapy afterloader quality assurance (QA) tool for simultaneously assessing the afterloader's positional, temporal, transit velocity and air kerma strength accuracy. Purpose: The purpose of this study was to develop a precise and rigorous technique for performing daily QA of HDR brachytherapy afterloaders, incorporating QA of: dwell position accuracy, dwell time accuracy, transit velocity consistency and relative air kerma strength (AKS) of an Ir‐192 source. Method: A Sharp ProGuide 240 mm catheter (Elekta Brachytherapy, Veenendaal, The Netherlands) was fixed 5 mm above a 256 channel epitaxial diode array 'dose magnifying glass' (DMG256) (Centre for Medical and Radiation Physics, University of Wollongong). Three dwell positions, each of 5.0 s dwell times, were spaced 13.0 mm apart along the array with the Flexitron HDR afterloader (Elekta Brachytherapy, Veenendaal, The Netherlands). The DMG256 was connected to a data acquisition system (DAQ) and a computer via USB2.0 link for live readout and post‐processing. The outputted data files were analyzed using a Python script to provide positional and temporal localization of the Ir‐192 source by tracking the centroid of the detected response. Measurements were repeated on a weekly basis, for a period of 5 weeks to determine the consistency of the measured parameters over an extended period. Results: Using the DMG256 for relative AKS measurements resulted in measured values within 0.6%–3.0% of the expected activity over a 7‐week period. The sub‐millisecond temporal accuracy of the device allowed for measurements of the transit velocity with an average of (10.88 ± 1.01) cm/s for 13 mm steps. The dwell position localization for 1, 2, 3, 5, and 10 mm steps had an accuracy between 0.1 and 0.3 mm (3σ), with a fixed temporal accuracy of 10 ms. Conclusion: The DMG256 silicon strip detector allows for clinics to perform rigorous daily QA of HDR afterloader dwell position and dwell time accuracy with greater precision than the current standard methodology using closed circuit television and a stopwatch. Additionally, DMG256 unlocks the ability to perform measurements of transit velocity/time and relative AKS, which are not possible using current standard techniques. [ABSTRACT FROM AUTHOR]

Background: Non‐melanoma skin cancer is one of the most common types of cancer and one of the main approaches is brachytherapy. For small lesions, the treatment of this cancer with brachytherapy can be done with two commercial applicators, one of these is the Large Field Valencia Applicators (LFVA). Purpose: The aim of this study is to test the capabilities of the LFVA to use clinically 60Co sources instead of the 192Ir ones. This study was designed for the same dwell positions and weights for both sources. Methods: The Penelope Monte Carlo code was used to evaluate dose distribution in a water phantom when a 60Co source is considered. The LFVA design and the optimized dwell weights reported for the case of 192Ir are maintained with the only exception of the dwell weight of the central position, that was increased. 2D dose distributions, field flatness, symmetry and the leakage dose distribution around the applicator were calculated. Results: When comparing the dose distributions of both sources, field flatness and symmetry remain unchanged. The only evident difference is an increase of the penumbra regions for all depths when using the 60Co source. Regarding leakage, the maximum dose within the air volume surrounding the applicator is in the order of 20% of the prescription dose for the 60Co source, but it decreases to less than 5% at about 1 cm distance. Conclusions: Flatness and symmetry remains unaltered as compared with 192Ir sources, while an increase in leakage has been observed. This proves the feasibility of using the LFVA in a larger range of clinical applications. [ABSTRACT FROM AUTHOR]

Concurrent chemo-radiation followed by high dose rate brachytherapy is the standard of care for locally advanced cervical cancer. The proximity of the ureters to the tumor volume risks ureteric stenosis. Here we outline the current understanding of radiotherapy induced ureteric stenosis in patients treated for cervical cancer, focusing on the incidence, risk factors, clinical consequences, and management. Searches on EMBASE, PubMed, Science Direct, and Google Scholar were performed for publications reporting on radiotherapy, cervix cancer and ureteric stenosis. Multi and single center, prospective/retrospective, cohort, and cross-sectional studies were included. This narrative review identified key issues relevant to radiation induced ureteric stenosis in cervical cancer in the literature. Thirteen studies were evaluated, identifying crude and actuarial rates of ureteric stenosis of 0.3–13.5% and 1.5–4.4% (at 5 years) respectively. The risk of ureteric stenosis is highest in the first 5 years after radiotherapy but continues to occur at a rate of 0.15% per year. Risk factors including advanced FIGO stage, tumor size >5 cm and baseline hydronephrosis increase the incidence of ureteric stenosis. EQD2 doses of ≥ 77Gy were significantly associated with ≥grade 3 ureteric morbidity. The majority of patients were managed with nephrostomy +/- ureteric stent insertion, with some requiring ureteral reimplantation, urinary diversion or nephrectomy. This review has identified multiple considerations, highlighting the need to identify patients highest at risk of ureteric stenosis. There is also a need to recognize ureters as organs at risk, record dose exposure, and apply dose constraints, all of which set the landscape for allowing dose optimization. [ABSTRACT FROM AUTHOR]

To compare patient and tumor characteristics, dosimetry, and toxicities between interstitial Syed-Neblett and intracavitary Fletcher-Suit-Delclos Tandem and Ovoid (T&O) applicators in high dose rate (HDR) cervical cancer brachytherapy. A retrospective analysis was performed for cervical cancer patients treated with 3D-based HDR brachytherapy from 2011 to 2023 at a single institution. Dosimetric parameters for high-risk clinical target volume and organs at risk were obtained. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 5.0. A total of 115 and 58 patients underwent Syed and T&O brachytherapy, respectively. Patients treated with Syed brachytherapy were more likely to have larger tumors and FIGO stage III or IV disease. The median D2cc values to the bladder, small bowel, and sigmoid colon were significantly lower for Syed brachytherapy. Patients treated with Syed brachytherapy were significantly more likely to be free of acute gastrointestinal (44% vs. 21%, p = 0.003), genitourinary (58% vs. 36%, p = 0.01), and vaginal toxicities (60% vs. 33%, p = 0.001) within 6 months following treatment compared to patients treated with T&O applicators. In contrast, Syed brachytherapy patients were more likely to experience late gastrointestinal (68% vs. 49%, p = 0.082), genitourinary (51% vs. 35%, p = 0.196), and vaginal toxicities (70% vs. 57%, p = 0.264). Syed-Neblett and T&O applicators are suitable for HDR brachytherapy for cervical cancer in distinct patient populations. Acute toxicities are more prevalent with T&O applicators, while patients treated with Syed-Neblett applicators are more likely to develop late toxicities. [ABSTRACT FROM AUTHOR]

Prostate cancer is the second most common cancer among men, with many treatment modalities available for patients, such as radical prostatectomy, external beam radiotherapy, brachytherapy, high-intensity focused ultrasound, cryotherapy, electroporation and other whole-gland or focal ablative novel techniques. Unfortunately, up to 60% of men with prostate cancer experience recurrence at 5 to 10 years. Salvage radical prostatectomy can be offered as an option in the setting of recurrence after a primary non-surgical treatment. However, the complexity of salvage radical prostatectomy is considered to be greater than that of primary surgery, making it the least popular treatment of choice. With the wide use of robotic platforms in urologic oncologic surgery, salvage radical prostatectomy has attracted attention again because, compared to past data, modern series involving salvage Robot-Assisted Radical Prostatectomy have shown promising results. In this narrative literature review, we comprehensively examined data on salvage radical prostatectomy. We investigated the correlation between the different types of primary prostate cancer therapy and the following salvage radical prostatectomy. Furthermore, we explored the concept of a robotic approach and its beneficial effect in salvage surgery. Lastly, we emphasized several promising avenues for future research in this field. [ABSTRACT FROM AUTHOR]

Purpose: To create and evaluate a three‐dimensional (3D) Prompt‐nnUnet module that utilizes the prompts‐based model combined with 3D nnUnet for producing the rapid and consistent autosegmentation of high‐risk clinical target volume (HR CTV) and organ at risk (OAR) in high‐dose‐rate brachytherapy (HDR BT) for patients with postoperative endometrial carcinoma (EC). Methods and materials: On two experimental batches, a total of 321 computed tomography (CT) scans were obtained for HR CTV segmentation from 321 patients with EC, and 125 CT scans for OARs segmentation from 125 patients. The numbers of training/validation/test were 257/32/32 and 87/13/25 for HR CTV and OARs respectively. A novel comparison of the deep learning neural network 3D Prompt‐nnUnet and 3D nnUnet was applied for HR CTV and OARs segmentation. Three‐fold cross validation and several quantitative metrics were employed, including Dice similarity coefficient (DSC), Hausdorff distance (HD), 95th percentile of Hausdorff distance (HD95%), and intersection over union (IoU). Results: The Prompt‐nnUnet included two forms of parameters Predict‐Prompt (PP) and Label‐Prompt (LP), with the LP performing most similarly to the experienced radiation oncologist and outperforming the less experienced ones. During the testing phase, the mean DSC values for the LP were 0.96 ± 0.02, 0.91 ± 0.02, and 0.83 ± 0.07 for HR CTV, rectum and urethra, respectively. The mean HD values (mm) were 2.73 ± 0.95, 8.18 ± 4.84, and 2.11 ± 0.50, respectively. The mean HD95% values (mm) were 1.66 ± 1.11, 3.07 ± 0.94, and 1.35 ± 0.55, respectively. The mean IoUs were 0.92 ± 0.04, 0.84 ± 0.03, and 0.71 ± 0.09, respectively. A delineation time < 2.35 s per structure in the new model was observed, which was available to save clinician time. Conclusion: The Prompt‐nnUnet architecture, particularly the LP, was highly consistent with ground truth (GT) in HR CTV or OAR autosegmentation, reducing interobserver variability and shortening treatment time. [ABSTRACT FROM AUTHOR]

This study employed a commercial software velocity to perform deformable registration and dose calculation on deformed CT images, aiming to assess the accuracy of dose delivery during the radiotherapy for lung cancers. A total of 20 patients with lung cancer were enrolled in this study. Adaptive CT (ACT) was generated by deformed the planning CT (pCT) to the CBCT of initial radiotherapy fraction, followed by contour propagation and dose recalculation. There was not significant difference between volumes of GTV and CTV calculated from the ACT and pCT. However, significant differences in dice similarity coefficient (DSC) and coverage ratio (CR) between GTV and CTV were observed, with lower values for GTV volumes below 15 cc. The mean differences in dose corresponding to 95% of the GTV, GTV-P, CTV, and CTV-P between ACT and pCT were − 0.32%, 4.52%, 2.17%, and 4.71%, respectively. For the dose corresponding to 99%, the discrepancies were − 0.18%, 8.35%, 1.92%, and 24.96%, respectively. These differences in dose primarily appeared at the edges of the target areas. Notably, a significant enhancement of dose corresponding to 1 cc for spinal cord was observed in ACT, compared with pCT. There was no statistical difference in the mean dose of lungs and heart. In general, for lung cancer patients, anatomical motion may result in both CTV and GTV moving outside the original irradiation region. The dose difference within the original target area was small, but the difference in the planning target area was considerable. [ABSTRACT FROM AUTHOR]

This scientific paper focuses on the treatment of breast cancer, one of the most common cancers among women. Despite increased awareness and the popularity of screening tests, statistics indicate a significant rise in incidence. The paper presents breast-conserving treatment methods, including brachytherapy, as a modern technique with promising outcomes. It describes the physical properties of ionizing radiation used in brachytherapy, discussing the photoelectric effect, Compton effect, and the phenomenon of pair production. The paper then delves into the biological effects of ionizing radiation, emphasizing the dependence on the cell cycle phase. It highlights lethal, sublethal, and potentially lethal cellular damage, categorizing the effects of radiation interaction into early and late responses. The discussion transitions to the application of brachytherapy in breast cancer treatment, focusing on various techniques such as LDR, PDR, and HDR. The paper provides a detailed description of brachytherapy's use in breast-conserving treatment, considering contraindications, treatment planning, and Accelerated Partial Breast Irradiation (APBI) techniques. The radioisotopes used in brachytherapy are also presented, with special attention to Iridium-192. The physical and practical aspects related to this isotope are discussed, along with other commonly used radioisotopes such as Cesium-137, Cobalt-60, and Strontium-90. The paper concludes with a summary, emphasizing the significance of brachytherapy in breast cancer treatment and outlining its prospects for development. The authors highlight precision and shortened therapy duration. Aim of the study The following paper aims to present a review of current knowledge regarding brachytherapy in the treatment of breast cancer and the treatment outcomes associated with this method. The main goal is to raise awareness among healthcare professionals about current issues with improvement of breast cancer treatment procedures based on brachytherapy. Materials and methods This article presents the current state of knowledge about brachytherapy for breast cancer, as found in various scientific articles. The following English keywords and their Polish equivalents were used to search Google Scholar's medical databases: brachytherapy, conservative treatment, breast cancer, BT, MammoSite. The most relevant articles on the subject were selected. [ABSTRACT FROM AUTHOR]

Background: High dose rate brachytherapy is commonly used in the treatment of prostate cancer. Treatment planning is often performed under transrectal ultrasound (US) guidance, but brachytherapy needles can be challenging to digitize due to the presence of poor US conspicuity and imaging artifacts. The plan accuracy and quality, however, are dependent on the proper visualization of the needles with millimeter accuracy. Purpose: This work describes a technique for generating a color overlay of needle locations atop the grayscale US image. Prototype devices were developed to produce vibrations in the brachytherapy needles that generate a high contrast color Doppler (CD) signal that highlights the needle locations with superior contrast and reduced artifacts. Denoted by the acronym color VISION (Vibrationally Induced Shimmering for Identifying an Object's Nature), the technology has the potential to improve applicator conspicuity and facilitate automated applicator digitization. Methods: Three prototype vibrational devices with frequencies between 200–450 Hz were designed in‐house and evaluated with needle implants in a phantom and cadaveric male pelvis using: (1) an actuator attached to the front of a prostate needle template; (2) an actuator attached to the top of the needle template; and (3) a hand‐held actuator with a stylet, inserted directly into a needle's inner lumen. Acquired images were postprocessed in MATLAB to evaluate the potential for automated digitization. Results: All prototype devices produced localized shimmering in implanted brachytherapy needles in both the axial and sagittal planes. The template mounted actuators provided better vibrational coupling and ease of operation than the stylet prototype. The Michelson contrast, or visibility, of the shimmering CD signal was 100% compared with ≤40% for B‐mode imaging of a single needle. Proof‐of‐principle for automated applicator digitization using only the CD signal was demonstrated. Conclusions: The color VISION prototype devices successfully coupled mechanical vibrations into brachytherapy needles to generate US CD shimmering and accurately highlight brachytherapy needle locations. The high contrast and natively registered signal are promising for future work to automate the needle digitization and provide a real‐time visual overlay of the applicator on the B‐mode US image. [ABSTRACT FROM AUTHOR]

Brachytherapy utilizes a multitude of radioactive sources and treatment techniques that often exhibit widely different spatial and temporal dose delivery patterns. Biophysical models, capable of modeling the key interacting effects of dose delivery patterns with the underlying cellular processes of the irradiated tissues, can be a potentially useful tool for elucidating the radiobiological effects of complex brachytherapy dose delivery patterns and for comparing their relative clinical effectiveness. While the biophysical models have been used largely in research settings by experts, it has also been used increasingly by clinical medical physicists over the last two decades. A good understanding of the potentials and limitations of the biophysical models and their intended use is critically important in the widespread use of these models. To facilitate meaningful and consistent use of biophysical models in brachytherapy, Task Group 267 (TG‐267) was formed jointly with the American Association of Physics in Medicine (AAPM) and The Groupe Européen de Curiethérapie and the European Society for Radiotherapy & Oncology (GEC‐ESTRO) to review the existing biophysical models, model parameters, and their use in selected brachytherapy modalities and to develop practice guidelines for clinical medical physicists regarding the selection, use, and interpretation of biophysical models. The report provides an overview of the clinical background and the rationale for the development of biophysical models in radiation oncology and, particularly, in brachytherapy; a summary of the results of literature review of the existing biophysical models that have been used in brachytherapy; a focused discussion of the applications of relevant biophysical models for five selected brachytherapy modalities; and the task group recommendations on the use, reporting, and implementation of biophysical models for brachytherapy treatment planning and evaluation. The report concludes with discussions on the challenges and opportunities in using biophysical models for brachytherapy and with an outlook for future developments [ABSTRACT FROM AUTHOR]

Surface mould brachytherapy is a conformal radiotherapy technique that can deliver high dose to the target while sparing nearby normal structures, Here, we aim to describe the procedurals details for high-dose rate (HDR) surface mould brachytherapy in sebaceous carcinoma of eyelid in a 54-year old lady. She was hesitant for surgery and any form of invasive intervention like interstitial brachytherapy. So, she was treated with surface mould HDR brachytherapy to a total dose of 52 Gy in 13 fractions at a dose of 4 Gy per fraction delivered twice daily using Iridium-192 isotope with no acute side effects. She was evaluated on a weekly basis for any radiation side effects and now she is disease-free for 6 months post-treatment with only mild dry eye. A detailed step-by-step procedure of surface mould technique, simulation procedure, dose prescription, planning, plan evaluation and treatment has been described in this paper. Surface mould HDR brachytherapy can be safely used as organ preserving modality of treatment for eyelid carcinoma. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study is to validate the dosimetric parameters of High Dose Rate 192Ir Flexi-source (mHDR v1 model) using GATE (version 9.1) Geant4-based Monte Carlo code, which is widely used in clinical applications for brachytherapy. This validation serves as a preliminary step toward investigating the issues related to tissue heterogeneities in brachytherapy dosimetry. Methods: In this study, the geometry of the 192Ir Flexi-source mHDR-v1 was simulated within a water sphere using GATE Monte Carlo code. The dosimetric parameters, including air kerma strength Sk, dose rate constant λ, radial dose function g(r), and anisotropy function F (r, θ), were computed in accordance with the TG- 43U1 and ESTRO guidelines, and the results were compared with available literature and clinical data for validation. Results: The dose rate constant obtained was 1.078 cGy h-1 U-1 ± 0.012 cGy h-1 U-1, showing a relative difference of 2.79% compared to the reference value. The radial dose function, starting from 0.25 cm to 15 cm, showed excellent agreement with a maximum of 3.43% at 15 cm. For the anisotropy function F (r, θ), the agreements were within 4.45% for 5<θ<175, and within 13.29% for all θ values. Conclusion: Results from this study demonstrate that the validation of the Flexi-source HDR192Ir source is achievable using the GATE based Monte Carlo simulation. Consequently, the GATE code can be employed to explore challenges associated with tissue heterogeneities in brachytherapy dosimetry for 192Ir Flexi-source. [ABSTRACT FROM AUTHOR]

Dynamic range is one of the primary limitations that restricts digital image sensors from acquiring more visual information. Current high dynamic range (HDR) imaging techniques entail a trade-off between dynamic range and visual fidelity. In this work, we propose a HDR imaging method, termed PE-HDR, to achieve both a wide dynamic range and high visual fidelity without additional complex post-processing algorithms. Instead of merging a bracketed exposure sequence, the PE-HDR captures HDR images in a single shot using optical coded pixel-wise exposure control, enabling cost-effective and flexible HDR imaging. By incorporating a differentiable optical encoder and a neural network decoder, we jointly optimize the imaging pipeline from light irradiance to digital image signals, thereby refining the pixel-wise exposure control strategy and improving image fidelity. Both simulations and experiments demonstrate that the proposed method achieves a dynamic range of up to 120 dB and an excellent visual fidelity with spatial resolution of up to 2560 × 1600 pixels. [ABSTRACT FROM AUTHOR]

Optical fibres are gaining popularity for relative dosimetry in proton therapy due to their spatial resolution and ability for near real-time acquisition. For FLASH proton therapy, these fibres need to handle higher dose rates and larger doses than for conventional proton dose rates. We developed a multi-point fibre sensor embedded in a 3D-printed phantom which can measure the profile of a FLASH proton beam. Seven PMMA fibres of 1 mm diameter were embedded in a custom 3D-printed plastic phantom of the same density as the fibres. The phantom was placed in a proton beam with FLASH dose rates at the TRIUMF Proton Therapy Research Centre (PTRC). The sensor was exposed to different proton energies, 13.5 MeV, 19 MeV and 40.4 MeV, achieved by adding PMMA bolus in front of the phantom and three different beam currents, varying the dose rates from 7.5 to 101 Gy/s. The array was able to record beam profiles in both transverse and axial directions in relative agreement with measurements from EBT-XD radiochromic films (transverse) and Monte Carlo simulations (axial). A decrease in light output over time was observed, which might be caused by radiation damage in the matrix of the fibre and characterised by an exponential decay function. [ABSTRACT FROM AUTHOR]

PURPOSE: Dynamic operations platforms allow for cross-platform data extraction, integration, and analysis, although application of these platforms to large-scale oncology enterprises has not been described. This study presents a pipeline for automated, high-fidelity extraction, integration, and validation of cross-platform oncology data in patients undergoing treatment for rectal cancer at a single, high-volume institution. METHODS: A dynamic operations platform was used to identify patients with rectal cancer treated at MD Anderson Cancer Center between 2016 and 2022 who had magnetic resonance imaging (MRI) imaging and preoperative treatment details available in the electronic health record (EHR). Demographic, clinicopathologic, tumor mutation, radiographic, and treatment data were extracted from the EHR using a methodology adaptable to any disease site. Data accuracy was assessed by manual review. Accuracy before and after implementation of synoptic reporting was determined for MRI data. RESULTS: A total of 516 patients with localized rectal cancer were included. In the era after institutional adoption of synoptic reports, the dynamic operations platform extracted T (tumor) category data from the EHR with 95% accuracy compared with 87% before the use of synoptic reports, and N (lymph node) category with 88% compared with 58%. Correct extraction of pelvic sidewall adenopathy was 94% compared with 78%, and extramural vascular invasion accuracy was 99% compared with 89%. Neoadjuvant chemotherapy and radiation data were 99% accurate for patients who had synoptic data sources. CONCLUSION: Using dynamic operations platforms enables automated cross-platform integration of multiparameter oncology data with high fidelity in patients undergoing multimodality treatment for rectal cancer. These pipelines can be adapted to other solid tumors and, together with standardized reporting, can increase efficiency in clinical research and the translation of actionable findings toward optimizing patient outcomes. A new software platform to aggregate patient data in an automated fashion! Real-world evidence to advance cancer care. [ABSTRACT FROM AUTHOR]

Tone-mapping algorithms aim to compress a wide dynamic range image into a narrower dynamic range image suitable for display on imaging devices. A representative tone-mapping algorithm, Retinex theory, reflects color constancy based on the human visual system and performs dynamic range compression. However, it may induce halo artifacts in some areas or degrade chroma and detail. Thus, this paper proposes a Retinex jointed multiscale contrast limited adaptive histogram equalization method. The proposed algorithm reduces localized halo artifacts and detail loss while maintaining the tone-compression effect via high-scale Retinex processing. A performance comparison of the experimental results between the proposed and existing methods confirms that the proposed method effectively reduces the existing problems and displays better image quality. [ABSTRACT FROM AUTHOR]

Purpose: To compare the dosimetric differences in vaginal brachytherapy (VBT) using single-channel vaginal cylinder (SCVC) and free-hand interstitial needles (FIN). Material and methods: Twenty-two women with malignant gynecologic tumors were prospectively treated with image-guided high-dose-rate (HDR) brachytherapy after surgery and external beam radiation therapy (EBRT). All HDR treatments were delivered using FIN implant technique. For dosimetric comparison purposes only, SCVCs of 2.5 cm diameter were placed in all patients. No sources were dwelled in cylinder applicator during clinical treatment. CT-guided brachytherapy treatment planning was performed according to GEC-ESTRO guidelines, with high-risk clinical target volume (HR-CTV) delineated based on clinical exams and MRI T2 sequences. Dose-volume parameters to HR-CTV and surrounding organs at risk (OARs) from interstitial plans were compared with those achieved from cylinder plans. Results: Compared with SCVC group, FIN group showed the same HR-CTV coverage. FIN group had higher V150% and V200% (p < 0.05). In addition, it had lower HI (p < 0.05). However, doses to the rectum D0.1cc (538.5 ±119.8 cGy), D1cc (415.4 ±73.3 cGy), D2cc (355.7 ±66.6 cGy), and Dmean (162.8 ±43.7 cGy) as well as the bladder D0.1cc (516.1 ±85.2 cGy) and D1cc (392.9 ±59.8 cGy) were lower in FIN group than in SCVC group (p < 0.05). Conclusions: FIN technique can be a dosimetrically preferable alternative to the commonly used SCVC for HDR VBT boost in patients with gynecological malignancies. It provides adequate coverage of target volumes, with minimal radiation dose to surrounding organs at risk. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was a retrospective dosimetric comparison of iridium-192 (192Ir) high-dose-rate (HDR) interstitial brachytherapy plans using model-based dose calculation algorithm (MBDCA) following TG-186 recommendations and TG-43 dosimetry protocol for breast, head-and-neck, and lung patient cohorts, with various treatment concepts and prescriptions. Material and methods: In this study, 59 interstitial 192Ir HDR brachytherapy cases treated in our center (22 breast, 22 head and neck, and 15 lung) were retrospectively selected and re-calculated with TG-43 dosimetry protocol as well as with Acuros™ BV dose calculation algorithm, with dose to medium option based on computed tomography images. Treatment planning dose volume parameter differences were determined and their significance was assessed. Results: For the breast planning target volume (PTV), TG-43 formalism calculated higher D90%, V95%, V100%, and V150% values than Acuros™ BV, ranging from 2.2% to 5.4% (mean differences), as it did for the head and neck cases, ranging from 2.5% to 4.7% and for the interstitial lung cases, ranging from 2.2% to 4.4%, showing statistical significance (p < 0.001). For the skin D0.1cm3, D0.2cm3, and D1cm3, the values were overestimated by TG-43, with a mean absolute differences of 1.4, 1.8, and 2.0 Gy, respectively for the breast, and 1.0 Gy for all DVH statistics for the head and neck cases compared with Acuros™ BV (p < 0.001). Ipsilateral lung V5Gy was also higher in TG-43-calculated plans, with a mean difference of 1.0% and 1.1% in the breast and lung implants, respectively. For the chest wall TG-43, the respective overestimation in D0.1cm3 and D1cm3 was 0.8 and 0.8 Gy for the breast, and 0.4 and 0.3 Gy for the interstitial lung cases, respectively. Conclusions: The TG-43 algorithm significantly overestimates the dose to PTVs and surrounding organs at risk (OARs) for breast, head and neck, and lung interstitial implants. TG-43 overestimation is in accordance with previous findings for breast and head and neck. To our knowledge, this is also exhibited for Acuros™ BV for the first time in interstitial lung HDR brachytherapy. [ABSTRACT FROM AUTHOR]

Aim: Health Technology Wales sought to evaluate the clinical and cost‐effectiveness of contact X‐ray brachytherapy (CXB) for early‐stage rectal cancer. Methods: Relevant studies were identified through systematic searches of MEDLINE, Embase, Cochrane Library and Scopus. A cost‐utility model was developed to estimate the cost‐effectiveness of CXB in National Health Service Wales, using results of the Organ Preservation in Early Rectal Adenocarcinoma (OPERA) trial. Patient perspectives were obtained through the Papillon Patient Support group and All‐Wales Cancer Network. Results: The OPERA randomized controlled trial showed that CXB improved complete response and organ preservation rates compared with external‐beam boost for people with T2–3b, N0–1, M0 rectal cancer who are fit for surgery. Managing more of this population non‐operatively after CXB was estimated to provide 0.2 quality‐adjusted life years at an additional cost of £887 per person. CXB was cost effective compared with external‐beam boost at a cost of £4463 per quality‐adjusted life year gained. This conclusion did not change in scenario analysis and CXB was cost effective in 91% of probabilistic sensitivity analyses. Patients valued receiving clear information on all available options to support their individual treatment choices. The detrimental impact of a stoma on quality of life led some patients to reject the idea that surgery was their only option. Conclusion: This evidence review and cost‐utility analysis indicates that CXB is likely to be clinically and cost effective, as part of a watch and wait strategy for adults fit for surgery. Wider access to CXB is supported by patient testimonies. [ABSTRACT FROM AUTHOR]

Background: Induced mutagenesis was employed in horse gram cv. CRIDA 1-18R with an objective of evolving mutants with increased yield potential. Methods: Based on preliminary study, the variety has been irradiated with desirable doses of gamma rays (200 Gy and 300 Gy), electron beam (100 Gy and 200 Gy) and its combination (100 Gy) and the material were forwarded to M2 generation following parentprogeny row basis. The genotypes exhibiting superior yield than control were further forwarded to M3 generation. Multivariate analyses were performed to determine the induction of micro-mutants for 11 quantitative traits. Result: The reduction in mean value over control was observed for most of the yield component traits at M2 generation. Among the mutagenic treatments, combination of gamma rays with electron beam registered high mean values for pod length (5.05 cm), number of pods per plant (54.42) and single plant yield (25.68 g) at M3 generation. Non-significant skewness and / or kurtosis at M3 population denoted the absence of epistatic interactions for plant yield. An increase in variability pattern, H2 and GAM at M3 generation indicated the scope for trait (plant height, number of seeds per pod, number of clusters per plant, number of pods per plant, biological yield and single plant yield) improvement through selection. [ABSTRACT FROM AUTHOR]

Background: The steep radiation dose gradients in cervical cancer brachytherapy (BT) necessitate a thorough understanding of the behavior of afterloader source cables or needles in the curved channels of (patient‐tailored) applicators. Purpose: The purpose of this study is to develop and validate computer models to simulate: (1) BT source positions, and (2) insertion forces of needles in curved applicator channels. The methodology presented can be used to improve the knowledge of instrument behavior in current applicators and aid the development of novel (3D‐printed) BT applicators. Methods: For the computer models, BT instruments were discretized in finite elements. Simulations were performed in SPACAR by formulating nodal contact force and motion input models and specifying the instruments' kinematic and dynamic properties. To evaluate the source cable model, simulated source paths in ring applicators were compared with manufacturer‐measured source paths. The impact of discrepancies on the dosimetry was estimated for standard plans. To validate needle models, simulated needle insertion forces in curved channels with varying curvature, torsion, and clearance, were compared with force measurements in dedicated 3D‐printed templates. Results: Comparison of simulated with manufacturer‐measured source positions showed 0.5–1.2 mm median and <2.0 mm maximum differences, in all but one applicator geometry. The resulting maximum relative dose differences at the lateral surface and at 5 mm depth were 5.5% and 4.7%, respectively. Simulated insertion forces for BT needles in curved channels accurately resembled the forces experimentally obtained by including experimental uncertainties in the simulation. Conclusion: The models developed can accurately predict source positions and insertion forces in BT applicators. Insights from these models can aid novel applicator design with improved motion and force transmission of BT instruments, and contribute to the estimation of overall treatment precision. The methodology presented can be extended to study other applicator geometries, flexible instruments, and afterloading systems. [ABSTRACT FROM AUTHOR]

The addition of a boost to the lumpectomy bed after whole-breast (WB) radiotherapy plays a key role in the treatment of patients with breast cancer (BC). The clinical benefits of a boost with high-dose-rate brachytherapy (HDR-BT) after conventional fractionation is supported by a large body of evidence. However, few studies have described its outcomes after a hypofractionated scheme. We included all patients treated with adjuvant WB-IMRT in 15 sessions followed by a single-session HDR-BT boost with local anesthesia on an outpatient basis. Between 2009 and 2017, 638 patients with early-stage BC were treated according to the aforementioned protocol after breast-conserving surgery. Median follow-up was 6 years (4–11). Despite the low incidence of side effects and their slightness, we did identify an impact of breast volume on the risk of acute radiodermatitis, fibrosis, pain and edema. However, we did not identify any relationship between the volume in cubic centimeters of the BT-implant with acute or long-term side effects. 2.2% patients had an actual local relapse, 2.4% a 2nd primary in the same breast and 2.39% were diagnosed with contralateral BC. Event-free survival at 11 years was 85.5% with an overall survival of 95.7%. Adjuvant hypofractionated whole-breast IMRT followed by a single dose HDR-BT boost has a low incidence of acute and chronic toxicity and excellent oncological outcomes. However, it may be worthwhile to intensify self-care protocols and surveillance in women with large breasts who may be at increased risk of side effects. [ABSTRACT FROM AUTHOR]

To Demonstrate the clinical validation of a machine learning (ML) model for applicator and interstitial needle prediction in gynecologic brachytherapy through a prospective clinical study in a single institution. The study included cervical cancer patients receiving high-dose-rate brachytherapy using intracavitary (IC) or hybrid interstitial (IC/IS) applicators. For each patient, the primary radiation oncologist contoured the high-risk clinical target volume on a pre-brachytherapy MRI, indicated the approximate applicator location, and made a clinical determination of the first fraction applicator. A pre-trained ML model predicted the applicator and IC/IS needle arrangement using tumor geometry. Following the first fraction, ML and radiation oncologist predictions were compared and a replanning study determined the applicator providing optimal organ-at-risk (OAR) dosimetry. The ML-predicted applicator and needle arrangement and the clinical determination were compared to this dosimetric ground truth. Ten patients were accrued from December 2020 to October 2022. Compared to the dosimetrically optimal applicator, both the radiation oncologist and ML had an accuracy of 70%. ML demonstrated better identification of patients requiring IC/IS applicators and provided balanced IC and IC/IS predictions. The needle selection model achieved an average accuracy of 82.5%. ML-predicted needle arrangements matched or improved plan quality when compared to clinically selected arrangements. Overall, ML predictions led to an average total improvement of 2.0 Gy to OAR doses over three treatment fractions when compared to clinical predictions. In the context of a single institution study, the presented ML model demonstrates valuable decision-support for the applicator and needle selection process with the potential to provide improved dosimetry. Future work will include a multi-center study to assess generalizability. [ABSTRACT FROM AUTHOR]

To present the outcome and toxicity results of a prospective trial of 21 Gy single fraction high-dose-rate (HDR) brachytherapy for men with low- or intermediate-risk prostate cancer. Patients were treated according to an IRB-approved prospective study of single fraction HDR brachytherapy. Eligible patients had low- or intermediate-risk prostate cancer with tumor stage ≤ T2b, PSA ≤ 15, and Gleason score ≤ 7. Patients underwent trans-rectal ultrasound-guided trans-perineal implant of the prostate followed by single fraction HDR brachytherapy to a dose of 21 Gy. The primary endpoint was grade ≥ 2 urinary/GI toxicity rates. Twenty-six patients were enrolled with a median follow up of 5.1 years and median age of 64 years. 88.5% of patients had T1 disease, 15.4% had Gleason score 6 (84.6% Gleason 7), and median pre-treatment PSA was 5.0 ng/mL. Acute and chronic grade ≥ 2 urinary toxicity rates were 38.5% and 38.5%, respectively. There were no grade ≥ 2 acute or chronic GI toxicities. Six (23.1%) patients experienced biochemical failure, six (23.1%) patients experienced radiographic local failure, and five (19.2%) patients had biopsy-proven local failure. No patients developed regional lymph node recurrence or distant metastasis. 5-year overall survival and cause-specific survival were 96.2% and 100%, respectively. 21 Gy single fraction HDR brachytherapy was associated with modestly higher-than-anticipated chronic urinary toxicity, as well as high biochemical and local failure rates. The results from this prospective pilot study do not support the use of this regimen in standard clinical practice. [ABSTRACT FROM AUTHOR]

In this systematic review and meta-analysis, we describe the oncologic and toxicity outcomes of definitive focal brachytherapy for prostate cancer. A PROSPERO registered study (CRD42023410170) was conducted following the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. PubMed, Embase, and The Cochrane Library were searched for studies between 2000 and 2022. Two authors independently performed the initial search. Biochemical recurrence-free survival (bRFS) was defined as the primary endpoint for the meta-analysis. Generalized linear mixed-effects models were conducted to calculate effect size and quantify heterogeneity. We also describe the side effects and local recurrence patterns of focal brachytherapy. Ten studies were identified and included 315 patients treated using focal brachytherapy as a definitive treatment. Mean (SD) age was 67.65 (7.9) years and mean (SD) PSA was 7.15 (2.7) ng/mL. Most patients (n = 236, 75%) underwent LDR Brachytherapy and 25% received HDR brachytherapy. Among the participants, 147 (46.5%) had a Gleason score ≤6, and 169 (53.5%) had a Gleason score ≥7. Only 11 (3.5%) patients received ADT. Overall, bRFS rate at median follow-up 4 years (Range: 1–6.42 years) was 91% (95% confidence interval [CI], 82–95%). Acute Grade ≤ 2 GU and GI toxicities were reported in 22 (7%) and 11 (3.5%) patients, respectively. Late Grade ≤ 2 GU and GI toxicity were reported in 6 (2%) and 14 (4.4%) patients, respectively. One case of prostate hemorrhage due to improper foley removal was noted but otherwise no acute or late Grade 3 or higher GI or GU toxicity related to radiotherapy was reported. Overall, definitive focal brachytherapy has a favorable toxicity profile. Oncologic outcomes are yet to mature. The evidence is limited by the small number of studies with low patients' number, across study heterogeneity, and possibility of publication bias. [ABSTRACT FROM AUTHOR]

Objective: To develop and validate a novel scoring system for predicting the risk of uterine perforation during brachytherapy (BT) in cervical cancer patients and to stratify patients based on this score to guide the use of ultrasound guidance during BT. Methods: Fifty patients with uterine perforation during BT between January 2018 and December 2020 were included. Common reasons for perforation were identified and a scoring system was developed. This was then applied to a cohort of 50 patients without perforation. The 2 cohorts were compared using the χ² test. To validate the scoring system, all newly diagnosed patients who underwent BT in 2021 were scored, and analysed using χ2 test and receiver operator characteristic curves. Results: The mean score in the test cohort was 10.16 (range=7-14) and 5.92 (range=5-8) for patients with and without perforation. In the validation cohort, the mean score was 6.9 (range=5-10) and 9.33 (range=7-11) for those with and without perforation. Patients with a score <8 were classified as low risk, while those with a score =8 were classified as high risk. Among the criteria evaluated for validation, response to external beam radiotherapy, uterine position, cervico-uterine angle (uterine flexion), identification of cervical os at BT assessment, and the total score were significant predictors, while previous history of perforation, uterine length, and additional uterine anomaly were not. Conclusion: The novel scoring system is an effective predictor of perforation risk during BT. Implementing this during BT assessment can optimize the need for ultrasound guidance during the procedure. [ABSTRACT FROM AUTHOR]