Surface brachytherapy (BT) lacks standard quality assurance (QA) protocols. Commercially available treatment planning systems (TPSs) are based on a dose calculation formalism that assumes the patient is made of water, resulting in potential deviations between planned and delivered doses. Here, a method for treatment plan verification for skin surface BT is reported. Chips of thermoluminescent dosimeters (TLDs) were used for dose point measurements. High-dose-rate treatments were simulated and delivered through a custom-flap applicator provided with four fixed catheters to guide the Iridium-192 (Ir-192) source by way of a remote afterloading system. A flat water-equivalent phantom was used to simulate patient skin. Elekta TPS Oncentra Brachy was used for planning. TLDs were calibrated to Ir-192 through an indirect method of linear interpolation between calibration factors (CFs) measured for 250 kV X-rays, Cesium-137, and Cobalt-60. Subsequently, plans were designed and delivered to test the reproducibility of the irradiation set-up and to make comparisons between planned and delivered dose. The obtained CF for Ir-192 was (4.96 ± 0.25) μC/Gy. Deviations between measured and TPS calculated doses for multi-catheter treatment configuration ranged from −8.4% to 13.3% with an average of 0.6%. TLDs could be included in clinical practice for QA in skin BT with a customized flap applicator.

Purpose: To compare dosimetric trade-offs among two full-VMAT and two hybrid 3D-CRT/VMAT strategies for left-sided whole-breast irradiation (WBI), and to evaluate the influence of planning strategy, introducing a novel tangential hybrid approach (H-tVMAT). Patients and Methods: Twenty patients with left-sided breast cancer treated with WBI (40.05 Gy in 15 fractions) were retrospectively analyzed. For each patient, four plans were generated within a single treatment planning system under free-breathing conditions: large-angle VMAT, tangential VMAT (tVMAT), Hybrid VMAT (H-VMAT), and the novel tangential Hybrid tVMAT (H-tVMAT). Primary dosimetric endpoints included heart and pulmonary structures and the contralateral breast, with dedicated evaluation of low-dose exposure. Target conformity, homogeneity index (HI), and monitor units (MUs) were also assessed. Results: All strategies achieved clinically acceptable target coverage and homogeneity. Hybrid configurations consistently reduced cardiac, pulmonary, and contralateral low-dose exposure compared with full-VMAT solutions. Among the evaluated strategies, H-tVMAT provided the most favorable balance between heart/LAD sparing, low-dose containment, and target coverage. Appropriately configured tangential VMAT achieved dosimetric results close to hybrid solutions, underscoring the importance of arc geometry. No statistically significant differences in delivery complexity were observed across strategies. Conclusion: Dosimetric performance in left-sided WBI is strongly influenced by planning implementation rather than nominal technique category alone. Hybrid tangential VMAT achieved the most balanced dosimetric profile, while optimized tangential VMAT provided comparable results. These findings support a strategy-specific approach to technique selection, emphasizing the central role of implementation choices in breast radiotherapy planning.

Brain metastases (BMs) represent the most common intracranial tumours in adults with advanced solid cancers, significantly impacting morbidity and mortality. While the emergence of systemic therapies such as immunotherapy (IT) and targeted therapy (TT) has improved survival outcomes, the interaction of these modalities with stereotactic radiotherapy/radiosurgery (SRS/SRT) remains poorly explored. This study aims to evaluate the safety, local control (LC), and efficacy of combining SRS/SRT with IT or TT in patients with BM. This prospective, monocentric study ("RaBITT Trial") analysed patients with BM treated with SRS/SRT using the CyberKnife system (Accuray) between May 2020 and May 2023. Patients received IT or TT in conjunction with SRS/SRT. Outcomes assessed included LC, overall survival (OS), disease-free survival (DFS), and next-line systemic treatment-free survival (NEST-FS). Toxicity, including radionecrosis and haemorrhage, was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 criteria. Statistical analysis employed Kaplan-Meier curves and univariate (UVA) and multivariate (MVA) regression models. We analysed 45 patients with a total of 225 BMs. The LC rate at 1 and 2 years was 85.7% and 79.8%, respectively. The overall response rate was 85.3%, with 56 complete responses (CRs). Multivariate analysis identified a higher biological effective dose with an α/β ratio of 10 and prescription isodose as predictors of CR. DFS rates at 1 and 2 years were 37.1% and 27.5%, respectively, while OS rates were 52.5% and 44.7%, respectively. NEST-FS rates at 1 and 2 years were 35.9% and 25.5%, respectively. Toxicity analysis revealed a radionecrosis rate of 20% for patients (6.7% of total lesions), with most cases being asymptomatic. Intralesional haemorrhage occurred in 1.7% of lesions, predominantly in melanoma and lung cancer patients. The combination of SRS/SRT with IT or TT yields high rates of LC and overall response with a manageable safety profile, emphasising the importance of personalised dosimetric planning and careful toxicity monitoring. Despite promising outcomes, the study's monocentric nature and limited sample size highlight the need for multicenter trials with extended follow-up to optimise treatment strategies and better understand long-term risks and benefits.

1. Prostate cancer remains one of the most prevalent malignancies in men worldwide. For patients with localized or locally advanced disease, radiotherapy (RT) represents a cornerstone of definitive...