Brachytherapy最新文献

Purpose: In surface brachytherapy, commercial applicators assist with catheter placement, but significant opportunities remain to further improve clinical efficiency. This study introduces the Montreal Mail, a novel modular 3D printed surface brachytherapy applicator, and compares its performance to that of two reference devices.

Methods: The Montreal Mail applicator features three generic components, including a 3D printed chainmail, impression paste, and a silicone pad. Each component was characterized radiologically using computed tomography (CT). An anthropomorphic hand phantom, configured to replicate the complex flexion deformity characteristic of Dupuytren's disease, was used to evaluate the Montreal Mail alongside two reference applicators: the Freiburg Flap (Elekta) and the Nova Surface (Adaptiiv Medical Technologies). For each applicator, the distance between catheter centers and the skin surface was quantified. Dosimetric accuracy was assessed using gamma index analysis of radiochromic film (Gafchromic EBT4) measurements.

Results: The radiological response of each component of the Montreal Mail applicator was found to be comparable to that of human tissues. The variability in source-to-skin distance was quantified using the interquartile range, which measured 1.8 mm for the Freiburg Flap, 1.4 mm for the Montreal Mail, and 0.6 mm for the Nova Surface applicator. Film-based dosimetric analysis demonstrated that all three applicators achieved gamma index passing rates above 96%, using the 3%/3 mm criterion relative to the planned dose distribution.

Conclusions: This study demonstrates that the Montreal Mail applicator is a practical solution that performs comparably to reference clinical devices in terms of surface adhesion and dose delivery. Moreover, its modular design offers a novel approach with the potential to enhance clinical efficiency.

Objectives: Despite the prevalence of prostate malignancies, there remains a need to improve toxicity profiles while maintaining oncologic control. Standard whole-gland treatment prescriptions have been associated with rectal, bladder, and urethral toxicity. This dosimetric study evaluated a differential dosing approach using Pd-103 low-dose-rate brachytherapy that delivers full prescription dose (125 Gy) to MRI-visible lesions while reducing dose to uninvolved prostate tissue (100 Gy).

Methods: Twenty-seven patients with unifocal, MRI-visible, biopsy-proven low- or intermediate-risk prostate cancer were identified. For each patient, two dosimetric plans were generated: a standard plan prescribing 125 Gy to the entire prostate, and a de-escalation plan prescribing 125 Gy to the MRI-visible lesion and 100 Gy to the remaining prostate. Dosimetric parameters including rectal D0.1cc and D2cc, bladder D2cc and D10cc, and urethral D10% and D30% were compared using Wilcoxon signed-rank tests.

Results: Fifty-four plans (27 standard, 27 de-escalation) were analyzed. The de-escalation approach achieved statistically significant dose reductions to all organs at risk (p < 0.0001). Median reductions were: rectum D0.1cc -10.77 Gy (17.7%), D2cc -5.99 Gy (17.4%); bladder D2cc -13.84 Gy (20.1%), D10cc -5.88 Gy (17.4%); and urethra D10% -35.47 Gy (22.5%), D30% -30.14 Gy (21.9%). Large effect sizes were observed for urethral doses (Cohen's d = 1.52-2.01).

Conclusion: MRI-guided differential dosing in Pd-103 LDR brachytherapy is technically feasible and achieves substantial reductions in organ-at-risk exposure, particularly urethral doses (>20%). While these dosimetric improvements suggest potential for reduced toxicity, clinical validation through our ongoing prospective Phase II trial is needed to confirm clinical benefit.

Objective: To explore the impact of radiation dosage on vital ocular structures to identify target dosage for vision preservation in patients with uveal melanoma treated with Eye Physics plaque brachytherapy.

Design: Retrospective study.

Subjects: Patients with choroidal melanoma treated with I-125 brachytherapy between 2017 and 2021 with at least 1-year follow up.

Methods: Retrospective chart review was performed. Time-to-event analysis was used to evaluate the effect of total dosage on ophthalmic structures. Other parameters analyzed include initial visual acuity, presence or absence of radiation retinopathy, tumor thickness, and tumor proximity to the fovea and optic nerve. Evaluation was based on 2 events: final best visual acuity of ≤20/200 and visual loss ≥5 lines from baseline. Univariate and multivariate Cox proportional hazards models were used for analysis.

Main outcome measures: Visual acuity at baseline and each follow up visit.

Results: One hundred thirty-six patients met inclusion criteria. Initial visual acuity was 20/20-20/40 in 71%, and ≤20/200 in 7% of patients. At final visit, 27% patients had 20/20-20/40 and 50% had ≤20/200. Higher total dose and average dose rate to the optic disc, fovea, lens, opposite retina and sclera were associated with worse visual outcomes. Foveal dosage <35 Gy resulted in the greatest proportion of patients maintaining useful vision followed by a dose of <27.5 Gy to the optic nerve.

Conclusions: <35 Gy to the fovea and <27.5 Gy to the optic disc results in >50% of patients maintaining useful vision and may represent dose target values and are important when considering neoadjuvant treatments prior to definitive plaque brachytherapy.

Background: Primary urethral cancer (PUC) is a heterogeneous and aggressive malignancy that accounts for less than 1% of all genitourinary malignancies. Due to its rarity, no prospective data exists to guide treatment paradigms. The purpose of this study is to report our clinical experience treating PUC with external beam radiation therapy (EBRT) with or without high-dose rate brachytherapy (HDR-BT) as part of curative-intent therapy.

Methods: Adult patients who had received treatment for PUC between January 2000 and December 2023 within a multi-center academic hospital system were queried in the medical record. Patients who received EBRT with or without HDR-BT as part of curative-intent treatment, including in the neoadjuvant, adjuvant, and definitive treatment settings, were included. Baseline clinicopathologic features, treatment details, and follow-up were recorded. The primary endpoint locoregional control (LRC), defined as the absence of recurrence at the primary site or regional lymph nodes, was estimated using the Kaplan Meier method and compared with the log-rank test. Cox regression analysis was performed to assess factors associated with LRC. A p-value of <0.05 was considered statistically significant.

Results: Seventy patients who received treatment for PUC were identified. Among these, 21 received EBRT as part of curative-intent treatment (including 8 in the adjuvant setting, 11 in the definitive setting, and 2 in the neoadjuvant setting). Among these 21 patients, 10 also received HDR-BT. The 2-year locoregional control rate was 100% versus 85.7% in patients who did and did not receive HDR-BT, respectively (p = 0.49). Univariate analysis did not show a significant correlation of sex, stage, race, receipt of systemic therapy, EBRT dose, or HDR-BT use with locoregional control. Among the 10 patients that received HDR-BT, one patient experienced a chronic grade 3 fistula, however, fistula was present after biopsy and before radiation. Two of the 10 patients experienced a grade 3 stricture which resolved over time with dilation. No patients experienced grade 4 or 5 toxicity.

Conclusions: PUC is a rare malignancy with little data to guide treatment paradigms. HDR-BT may offer improved locoregional control with acceptable toxicity in this small study. Larger studies are needed to refine optimal therapeutic approach and radiation treatment technique.

Purpose: Fractionated HDR brachytherapy, following external beam radiotherapy, is essential for treating locally advanced cervical cancer. Modern techniques enable the delivery of multiple fractions with a single application. However, application process and removal cause significant pain and distress. With no standardized guidelines for anesthesia in gynecological brachytherapy, this study surveyed current anesthesia practices across India to better understand the variability.

Methods and materials: A survey was conducted using an online questionnaire distributed to radiation oncologists via social media platforms (survey instrument: Rivera et al., 2024). Analysis was done using descriptive statistics.

Results: Ninety-three responses were received, excluding 14 repeats; 79 responses were analyzed. Most of the respondents were male (52%). The most common place for intracavitary application is a dedicated brachytherapy suite. Spinal anesthesia, alone or in combination, was the most frequently used technique for intracavitary (39%), hybrid (30%), and interstitial (36%) brachytherapy. Most institutions are doing >20 applications per month. During waiting periods and treatments, oral analgesia is most commonly used. Nearly half (49%) of respondents perceived the procedure as distressing, yet fewer than half (44%) reported implementing measures to reduce psychological distress. Compared with Western data, Indian practice is characterized by higher procedure volumes, a greater reliance on regional anesthesia, and limited use of conscious sedation.

Conclusion: We observed clinician preference for a specific analgesic modality, highlighting clinician bias in pain control during gynecological brachytherapy. Analgesia and anesthesia during waiting times and applicator removal are areas of interest and shall be explored further. There is a need for good evidence for better management of pain and distress associated with gynecological brachytherapy.

Purpose: To assess the clinical efficacy and feasibility of combining MRI-guided radiofrequency ablation (RFA) with ¹²⁵I seed brachytherapy for hepatocellular carcinoma (HCC) adjoining large vessels (≥3 mm diameter).

Materials and methods: This single-center, retrospective cohort study analyzed prospectively collected data from March 2010 to March 2017. Approved by the institutional ethics review board, this retrospective analysis evaluated 84 patients with HCC situated near major vasculature, treated from March 2010 to March 2017. A total of 97 tumors underwent MRI-guided RFA combined with ¹²⁵I seed implantation. Outcome measures included technical success, overall survival (OS), recurrence-free survival, local tumor progression, and comparative analyses between treatment-naive and previously treated subgroups.

Results: All interventions were completed without complications, achieving a primary technical efficacy rate of 98.81% (83/84). Postimplantation dosimetry confirmed adequate coverage in all cases (median D90 118 Gy, V100 94%). No seed migration or radiation-related toxicity (including radiation-induced liver disease) was recorded. The mean OS was 30.96 ± 18.98 months, with 1-, 3-, 5-, and 7-year OS rates of 100%, 98.20%, 87.10%, and 72.80%, respectively. Disease recurrence developed in 38.10% (32/84) of patients at a mean of 16.84 ± 13.61 months. Local tumor progression occurred in 7.1% (6/84). Significant intergroup differences emerged in portal hypertension (p = 0.009) and baseline AFP levels (p = 0.0015), with the treatment-naïve group demonstrating superior survival outcomes (p = 0.012).

Conclusions: The combined approach of MRI-guided RFA and ¹²⁵I brachytherapy represents a safe and effective strategy for managing HCC near major vasculature, providing high technical success rates and durable survival outcomes. Early intervention in treatment-naïve patients may be critical for outcome optimization. Prospective multicenter trials with extended follow-up are warranted to confirm these observations.

Purpose: To present comprehensive development and evaluation methodologies for a generalizable deep learning (DL)-driven autocontouring model of standard pelvic organs-at-risk (OARs) in MRI-planned cervical brachytherapy.

Materials and methods: A curated dataset of 200 3D-MRIs (85% training/validation, 15% testing) including multiple applicator types, varying treated anatomies, and manual contours of OARs (bladder, rectum, sigmoid, small bowel) by 3 physicians was utilized to develop an nnU-Net-based autocontouring model. Iterative tuning was conducted to determine the optimal hyperparameters and enhance evaluation metrics. Model performance was assessed using quantitative metrics, like geometric (e.g., Dice Coefficient (DC) and Hausdorff Distance 95th Percentile (HD95)) and dosimetric (dose-volume histograms (DVHs), dose differences (ΔD2cc)), and then correlated with qualitative physician-review (modified Turing and Likert tests).

Results: Geometric metrics were best for bladder (e.g., mean ± SD DC|HD95(mm) 0.93 ± 0.02|2.26 ± 1.07) with greater variability exhibited for small bowel (0.62 ± 0.16|24.90 ± 14.36). Dosimetric comparisons of manual vs predicted contours showed high agreement in DVHs, with mean ΔD2cc <0.60 Gy EQD2₃ across all OARs. Model performance was consistent, irrespective of applicator type, OAR volume, or contourer. Quantitative scores in support of DLM were not always associated with as favorable qualitative results, yet physician-review showed clinical acceptability (80% for bladder and rectum).

Conclusion: The DL-based autocontouring model, trained on a heterogeneous in-house dataset, demonstrates clinical acceptability for OARs as determined by comprehensive evaluation. It also shows promise for translatability to target contouring, and adaptability to other gynecological (noncervix) brachytherapy applications. Differences in qualitative and quantitative results exist; directionality and magnitude should be considered in clinical usability assessments of brachytherapy autocontouring models.

Introduction: Brachytherapy boost improves biochemical disease-free survival (bDFS) for intermediate/high-risk prostate cancer, but may increase toxicity. We prospectively assessed tumor control, survival, toxicity, and quality of life (QoL) in a large cohort treated with high-dose-rate (HDR) brachytherapy boost after hypo-fractionated external beam radiotherapy (EBRT) and assessed predictors for tumor control and survival.

Methods and materials: From 2010 to 2020 patients received EBRT (58 Gy in 20 fractions to prostate/seminal vesicles or 62.5 Gy in 25 fractions with 50 Gy to pelvic nodes), followed by a 10 Gy HDR brachytherapy boost, and androgen deprivation therapy (ADT) up to 3 years. Biochemical recurrence was defined by the Phoenix criterion. Toxicity (CTCAE v3.0) and QoL (IPSS, Likert scales for bowel and erectile function) were prospectively recorded. Outcomes were analyzed using Kaplan-Meier analysis and Cox/competing-risk models.

Results: Among 274 patients (267 high risk), median follow-up was 95 months. Eight-year bDFS and overall survival (OS) were both 76%, and prostate cancer-specific survival (PCASS) 95%. PSA nadir > 0.1 ng/mL was the strongest predictor for biochemical failure and PCASS (8-year bDFS: 88% vs. 31%, p < 0.001). Longer time to PSA nadir improved tumor control and survival. Late Grade 3 genitourinary toxicity occurred in 4.4% and gastrointestinal in 0.7%. Median IPSS increased from 7 to maximum 10 (p < 0.001), minor bowel symptoms from 3% to maximum 13%. Complete erectile dysfunction rose from 18% to maximum 47% (p < 0.001).

Conclusion: EBRT with ADT and HDR brachytherapy boost provides durable tumor control with acceptable long-term toxicity. PSA nadir and time to nadir are strong predictors for outcomes and may support personalized follow-up strategies.

Purpose: This study aimed to evaluate the efficacy and safety of combining transarterial chemoembolization (TACE) with 125Iodine (125I) seed implantation for the treatment of recurrent hepatocellular carcinoma (HCC) following radiofrequency ablation (RFA).

Method: A retrospective analysis was conducted on 221 HCC patients treated between January 2016 and January 2025, divided into two groups: TACE monotherapy (n = 132) and TACE combined with 125I seed implantation (TACE-125I, n = 89). Treatment outcomes, including overall survival (OS), progression-free survival (PFS), and recurrence patterns, were assessed. Complications were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE v5.0).

Results: The TACE-125I group demonstrated significantly improved survival outcomes compared to the TACE group, with a median OS of 38 months (95% CI: 34.6-41.4) versus 21 months (95% CI: 14.6-27.4) (p < 0.001) and a median PFS of 19 months (95% CI: 13.7-24.3) versus 10 months (95% CI: 7.8-12.2) (p < 0.001). Local recurrence rates were lower in the TACE-125I group (10 cases vs. 20 cases). The safety profile was favorable, with no severe complications or procedure-related fatalities. Multivariate analysis identified the neutrophil-to-lymphocyte ratio (NLR) as an independent prognostic factor for both OS and PFS.

Conclusions: The combination of TACE and 125I seed implantation significantly improves survival and local tumor control in recurrent HCC after RFA, offering a promising therapeutic option for patients with limited treatment alternatives. Further prospective studies are needed to validate these findings and optimize patient selection criteria.

Background: Palladium-103 (Pd-103) brachytherapy has been associated with excellent oncologic outcomes for favorable risk prostate cancer. Our purpose was to evaluate whether de-escalated dose Pd-103 was associated with a difference in biochemical failure (BF) compared with standard-dose Pd-103 for low-risk prostate cancer.

Materials and methods: Patients with low-risk prostate cancer (cT1b-T2b, Gleason 6, and prostate-specific antigen (PSA) ≤ 10 ng/mL) were randomized 1:1 to standard dose (125 Gy) versus de-escalated dose (110 Gy) Pd-103 brachytherapy. The primary endpoint was biochemical failure (BF), defined as PSA ≥ 0.4 ng/mL. Fine-Gray regression analysis was used to identify baseline factors associated with BF, with death as a competing risk. Grade 3 genitourinary (GU) and gastrointestinal (GI) toxicities were reported.

Results: This analysis included 316 patients, who were randomized between February 2006 and February 2014. At a median follow-up of 11.0 years, the 12-year cumulative incidences of BF for the standard and de-escalated dose arms were 1.3% and 2.7%, respectively (p = 0.40). On multivariate regression, body mass index (adjusted sub-distribution hazard ratio (sHR): 1.18; 95% confidence interval (CI) = 1.06-1.32; p = 0.003) and PSA (adjusted sHR: 1.76; 95% CI = 1.36-2.28; p < 0.001) were associated with BF. Cumulative incidences of Grade 3 GU toxicities at 12-years were 6.5% and 3.9% for standard and de-escalated arms, respectively (p = 0.34). There were no Grade 3 GI toxicities in either arm.

Conclusions: De-escalated dose Pd-103 (110 Gy) could be considered for patients with low-risk prostate cancer who opt for definitive treatment.