Brachytherapy Research Articles (Page 1)

Advances in imaging modalities and radiotherapy (RT) technologies have enabled the development of focal RT approaches for localized prostate cancer (PCa). This systematic review aims to evaluate the oncological and toxicity outcomes of focal or partial-gland RT, while also discussing the optimal patient selection criteria and treatment planning strategies for this emerging approach. This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was performed on February, 2025, on Pubmed, with the keywords "focal RT" and "definitive" and "prostate cancer"; and "focal brachytherapy (BT)" and "definitive" and "prostate cancer". Both focal BT and partial-gland stereotactic body radiotherapy (SBRT) strategies demonstrated a minimal impact on toxicity and quality of life parameters. Only a transient increase in urinary frequency was suggested at 6-12 months following focal treatment, returning to baseline thereafter. In highly selected low-risk (LR) and intermediate-risk (IR) PCa patients with both excellent radiological-histological concordance and a limited number of positive cores, focal RT demonstrated excellent biochemical relapse-free survival and metastasis-free survival, reaching up to 97% and 100% at 5 years. Subsequent intraprostatic relapse mostly occurred out-of-field, and were salvaged with either focal treatment or radical prostatectomy, with no signal of increased risk of severe toxicity. Focal RT is associated with low toxicity rates, and excellent oncological outcomes. However, most studies recruited LR or favorable IR PCa, including patients eligible for active surveillance. Results from ongoing and future studies evaluating focal RT in IR PCa patients not eligible for active surveillance, and incorporating advanced imaging for target volume definition are eagerly awaited.

Thermal bridging due to high-conductivity metal elements in steel-framed systems can affect building performance. The presence of thermal bridges, radiative heat exchange between air-facing surfaces, and natural convection driven by buoyancy effects within cavities contribute to complex 3D airflow and heat transfer phenomena within these systems. With the wide range of reflective and mass insulation properties used in steel-framed wall assemblies, this study employs a previously developed and validated 3D numerical model to evaluate the thermal performance of a reflective insulation system (RIS) and a hybrid system that integrates reflective insulation with conventional mass insulation. Additionally, a methodology aligned with ASTM C1224 is introduced for separating the thermal bridging effects of steel framing elements to allow for evaluating the thermal resistances of wall cavities in RIS and hybrid systems. This work demonstrates, for the first time to the author’s knowledge, the coupled effects of conduction, convection, radiation, and airflow in steel-framed assemblies incorporating reflective insulation with and without conventional mass insulation. It further identifies a previously unreported critical conductivity threshold where partial and full cavity insulation yield equivalent resistance and provides data to extend current standards that omit RIS. The findings indicate that for mass insulation materials with low thermal conductivity, wall systems in which cavities are completely filled with insulation exhibit greater thermal resistance than those with only partially filled cavities. However, as the thermal conductivity of the insulation increases, the trend reverses, with partially filled cavities providing higher thermal resistance than completely filled ones. There exists a critical thermal conductivity threshold at which the thermal resistance of both configurations becomes equivalent. Beyond this point, wall systems with less insulation in their cavities can achieve superior thermal resistance to those where the cavities are completely filled. Given that existing design guidelines, such as Thermal Design and Code Compliance for Cold-Formed Steel Walls, do not currently address RIS, the data generated in this study provide a foundation for future updates. By integrating RIS and hybrid systems into thermal design practices, this research supports the development of cost-effective, high-performance steel-framed wall systems that enhance energy efficiency while maintaining material and regulatory compliance.

Bilayer nanofiber-coated stent integrating internal radiation and spatiotemporal IL-12 release promotes antitumor immune response.

Deep learning-based automatic dose optimization for brachytherapy.

MUlticentre REtrospective comparison of definitive EBRT with or without HDR BRAchytherapy boost in patients with locally-advanced prostate cancer and regional lymph NOde metastases (MUREBRANO) - A propensity score matched analysis.

Helium 4He nuclei based radiotherapy.

Re-irradiation in patients affected by prostate cancer and relapsing after previous definitive or postoperative radiotherapy. An international registry based study on behalf of Italian association of radiotherapy and clinical oncology (AIRO). (RE-START).

Quantitative assessment of uranium and alpha-emitting radionuclides in lung cancer patients using CR-39 Detectors: Influence of gender and smoking behavior.

Prospective cohort study to validate esophageal dose constraints and predictive models for esophagitis in patients with breast cancer undergoing hypofractionated regional nodal radiotherapy.

Evaluating the accuracy of SPECT/CT LSF estimations in SIRT therapies using Monte Carlo simulations with virtual 4D anthropomorphic phantoms.

MIR dosimetry using CR-39 based α spectroscopy.

Accurate absorbed dose assessment is crucial for personalized hyperthyroidism treatment, but challenges remain in calculating the thyroid dose of 131I using the medical internal radiation dose (MIRD) schema. Further exploration is needed to improve image segmentation for personalized thyroid phantoms, assess uncertainty in S value calculations, and compare dose estimates between the MIRD schema and the Marinelli-Quimby formula. This work aims to design a multi-scale deep learning model to enhance accuracy and reliability in absorbed dose calculations for hyperthyroid patients based on the MIRD schema. To improve multi-scale semantic learning and integration, multi-scale residual and multi-head attention modules were added to the UNet++ architecture. An information entropy-based uncertainty quantification module was proposed to assess segmentation confidence and enhance reliability. Patient-specific thyroid voxel phantoms were created from clinical segmentation results, S values were calculated, and overall uncertainty was evaluated. Finally, absorbed dose differences between the MIRD schema and Marinelli-Quimby formula were compared. The comparative experiments on the publicly available head and neck organ-at-risk CT and MR segmentation (HaN-Seg) dataset showed that the MSRA-UNet++ model excelled in segmenting multiple organs. Specifically, for thyroid segmentation, the proposed model achieved a Dice Similarity Coefficient (DSC) of 88.23% and a Hausdorff Distance 95% (HD95) of 9.43 pixels. When applied on clinical dataset, Jaccard Index (JI) improved 6.17%, compared to UNet++. The uncertainty quantification results showed higher uncertainty at the thyroid edges and low uncertainty in the interior. Patient-specific phantoms were created from segmentation results, and the S value was calculated using Monte Carlo method. Time-integral activity was determined by radioiodine kinetics data. The absorbed dose was evaluated using the MIRD schema and compared with the Marinelli-Quimby formula, which overestimated the MIRD schema by an average of 7.74%. The proposed MSRA-UNet++ network provides segmentation results with estimated uncertainty and higher accuracy. The reliability of S values was enhanced by combining segmentation uncertainty with Monte Carlo simulations. To the best of our knowledge, this study is the first to introduce an uncertainty quantification module into the CT image segmentation process for hyperthyroid patients. Additionally, it combines patient-specific thyroid voxel phantoms with individualized radioiodine kinetics data to assess the absorbed dose using the MIRD schema, with the results compared to the Marinelli-Quimby formula. The code will be release on https://github.com/410435553.

High-dose-rate (HDR) plesiotherapy with flap for the treatment of non-melanoma skin cancer.

Radiomics-based machine-learning approach to predict response at brachytherapy using pretreatment magnetic resonance imaging in locally advanced cervical cancer.

Abstract Despite the internal tides are well-known at mid-latitudes due to their strong energy and long-range propagation, near the equator, internal tides are generally too weak to receive sufficient research interest. Utilizing combined numerical simulations and altimeter data, we reveal an M 2 internal tidal beam, originating from the Mussau Ridge with a weak generation of 0.51 GW, radiating much further than expected across the Caroline Basin. The joint effects of the ridge-trench-rise topography, negligible equatorial earth rotational force, South Equatorial Current refraction and a shallow and thin thermocline combined to induce this long-range propagation. Dissipation occurs locally near the source, but also remotely within the Caroline Basin due to the long-range propagation. Upper layer dissipation reaches 10 −9 W/kg, one to two orders of magnitude higher than near the seafloor, and only 21.5% of the total dissipation occurs below 1000 m. The remote dissipation presents the multilayer distribution, first decreasing downward and then increasing near the seafloor. The calculated internal tidal dissipation rates were generally consistent with fine-scale parameterizations, except where f approaches zero, where fine-scale parameterization becomes completely inapplicable. Our study highlights the importance of equatorial internal tide dissipation especially below the thermocline, which should be understood reliably and parameterized differently in ocean and climate models.

Posthepatectomy liver failure (PHLF) remains the leading cause of morbidity and mortality following major liver resection. The preoperative conditioning of the future liver remnant (FLR) is therefore essential to optimize the resectability and avoid postoperative complications. The aim of this review article is the presentation and critical evaluation of current strategies for liver conditioning, including interventional, surgical and systemic strategies. Aselective literature search for databases was conducted in PubMed. The focus was on recent systematic reviews, randomized trials and registry analyses addressing portal vein embolization (PVE), liver venous deprivation (LVD), associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), selective internal radiation therapy (SIRT) and neoadjuvant chemotherapy. The PVE procedure has been the established standard for decades, with proven safety and reliable induction of hypertrophy but shows limitations due to insufficient growth or tumor progression in up to 20% of patients. In numerous studies the LVD procedure demonstrated a more rapid and extensive hypertrophy of the FLR compared with PVE, without compromising safety. The ALPPS provides the highest regeneration dynamics but is associated with high morbidity and mortality and requires strict patient selection. The SIRT (radiation lobectomy) enables both tumor control and a relevant compensatory hypertrophy, even though prospective comparative trials are lacking. Neoadjuvant chemotherapy, particularly FOLFOXIRI plus bevacizumab or biomarker-based treatment regimen selection, leads to high conversion and resection rates in initially nonresectable metastases. The current evidence shows that individualized strategies for liver conditioning are decisive to enable a safe resection. The selection of the procedure should be oriented to the patient characteristics, tumor biology and interdisciplinary treatment algorithms.

BACKGROUND: Renogram using Technetium-99m Diethylene Triamine Pentaacetic Acid (Tc-99m DTPA) is applied to evaluate renal perfusion, glomerular filtration rate (GFR), and urinary excretion. In patients with impaired renal function, delayed tracer elimination may increase accumulation in non-target organs such as the heart and liver, resulting in greater radiation exposure and reduced image quality. Studies examining the relationship between renal function and Tc-99m DTPA dose distribution remain limited, particularly in clinical settings in Indonesia. Therefore, in this study, an organ-level quantitative analysis of Tc-99m DTPA radiopharmaceutical dose distribution and absorbed dose using the Medical Internal Radiation Dose (MIRD) approach based on Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) imaging was performed.METHODS: Thirty adult patients undergoing renogram were categorized into low-GFR (<60 mL/min/1.73 m²) and high-GFR (≥60 mL/min/1.73 m²) groups. Each patient received 4–5 mCi of Tc-99m DTPA intravenously. Organ activities were obtained from regions of interest (ROIs) on SPECT/CT images, and organ-level absorbed doses (mGy) were calculated using the MIRD formalism.RESULTS: In the low-GFR group, tracer retention in non-target organs increased, with absorbed doses up to twofold higher in the heart (0.0002–0.0136 mGy) and liver (0.0010–0.0178 mGy) compared to the high-GFR group. Renal absorbed doses ranged from 0.0001–0.0694 mGy, showing no significant difference between the left and right kidneys, while significant differences were observed in the heart and liver.CONCLUSION: GFR significantly affects the radiopharmaceutical dose distribution and absorbed dose of Tc-99m DTPA. Reduced renal function increases radiation exposure in non-target organs, whereas normal function results in a more localized renal dose distribution.KEYWORDS: Tc-99m DTPA, renogram, MIRD, glomerular filtration rate, absorbed dose, SPECT/CT, nuclear medicine

Intra-arterial radioembolization (RE) with radiopharmaceuticals based on microspheres labeled with beta-emitting radionuclides is one of the most promising methods of inoperable liver cancer treatment. Phase 1 and 2 of clinical trials of a domestic radiopharmaceutical based on albumin microspheres with a diameter of 20—40 μm, labeled with rhenium-188 («MSA 20—40 μm, 188Re») has already been completed. Objective. To study the distribution of radiopharmaceutical «MSA 20—40 μm, 188Re» in the body of patients after radioembolization, to determine the individual absorbed doses of tumor lesions and risk organs of patients, and the local radiation doses of personnel. Material and methods. Radiopharmaceutical «MSA 20—40 μm, 188Re» with activities ranged from 3.1 MBq to 6.5 MBq was used for intra-arterial RE in 50 patients (18 females and 32 males) with primary liver cancer (C22.0, C22.1, C22.2, C22.9) and metastatic liver cancer (C18.0, C18.6, C18.7, C19.0, C20.0, C97). Scintigraphy and SPECT/CT of the whole body were performed at 1, 24, 48, and 72 h after RE. Radiometry of urine samples, which was taken for 48 h after RE, was carried out. The calculation of absorbed doses was performed according to recommendations of Medical Internal Radiation Dose (MIRD). To measure local radiation doses of medical personnel luminescent microdosimeters were used. Results. The urinary excretion of 188Re in patients of Phase I of clinical trials was on averaged 22.8%, decreasing to 13.6% after updating of radiopharmaceutical synthesis technology. A small (3.4%-13.4%) pulmonary shunt was observed in all patients. Absorbed doses in tumor lesions ranged from 4.6 Gy to 68.5 Gy, depending on administered activities and lesions volume. The values of individual radiation doses in critical organs of patients were significantly lower than the commonly applied dose constraints in radiotherapy. No personnel dose limits were exceeded in accordance with Radiation safety standards-99/2009. Conclusion. High stability of «MSA 20—40 μm, 188Re» during radioembolization procedure ensures the delivery of significantly higher absorbed doses in tumor foci as compared with risk organs of patients with inoperable liver cancer.

Purpose. To assess the efficacy of eye-saving treatment (involving transpupillary thermotherapy (TTT) combined with strontium-90 (Sr90)/ yttrium-90 (Yt90) brachytherapy (BT)) for medium and large CM in terms of local tumor control rate at 12 months after the initiation of treatment. Material and Methods: This retrospective cohort study included 283 patients with CM who were treated at SI “The Filatov Institute of Eye Diseases and Tissue Therapy of the National Academy of Medical Sciences of Ukraine” from 2007 to 2024. The study sample consisted of 125 men (44.2%) and 158 women (55.8%), with a mean age (standard deviation) of 54.2 (12.4) years. Short-term success was defined as evidence of complete tumor regression, partial tumor regression or stabilization of the tumor process at 12 months after the initiation of treatment. Short-term failure was defined as evidence of continued tumor growth, tumor recurrence (a tumor growing from the scar) or extrabulbar spread at 12 months after the initiation of treatment. Results: Short-term treatment success was achieved in 274 patients (96.8%). Particularly, complete tumor regression was achieved in 86/274 patients (31.4%) or 86/283 patients (30.4%), partial tumor regression, in 165/274 (60.3%) or 165/283 (58.3%), and regression with stabilization of tumor size, in 23/274 (8.4%) or 23/283 (8.1%). Local treatment failure in the form of continued tumor growth was seen in 9/283 patients (3.2%) and led to enucleation. Conclusion: More effective outcome of the eye-saving treatment (involving TTT combined with Sr90/ Yt90 BT) for CM may be expected in patients with T1 stage (tumor thickness of 3.1-6.0 mm and base diameter of 3.1-9.0 mm), T2 stage (3.1-9.0 mm; 3.1-15.0 mm), and T3 stage with category 4 tumor size (tumor thickness of 3.1-6.0 mm and base diameter of 15.1-18.0 mm) and category 5 tumor size (6.1-9.0 mm; 12.1-18.0 mm).

Accurate estimation of absorbed doses in organs/tissues is essential for effective internal dosimetry. This is especially the case for positron-emission tomography-utilized radiopharmaceuticals that contain positron-emitting radionuclides. To achieve this, it is essential to calculate S-coefficients (S), basic coefficients representing the absorbed dose in the target organ per unit of nuclear transformation in the source organ. In addition, as the evolution of computational phantoms from stylized, voxelized, to mesh-type models continues, updating the S-coefficients to correspond with the new phantom generation becomes required. We employed the DoseCalcs Monte Carlo platform to estimate S-coefficients for four positron-emitting radionuclides, namely, C-11, N-13, O-15, and F-18. Based on decay and energy data for emitted positrons that were obtained from ICRP Publication 107, the simulations involved 24 regions as internal radiation sources in the male and female mesh-type phantoms of the International Commission on Radiological Protection (ICRP). We calculated the S-coefficients for 25 radiosensitive target regions. The graphs of S-coefficients for all target source pairs exhibit similar trends for the four radionuclides. We compared the results with the OpenDose database, which calculated S-coefficients for voxelized phantoms. The comparison showed that the S-coefficients and the OpenDose voxelized values were very close for most target regions in the mesh-type phantoms. However, discrepancies were observed in specific cases, such as thyroid UBCs and liver HeW. These discrepancies arise primarily from the differences in organs/tissues locations and shapes, as well as the differences in material composition, which is distributed across the large inter-distance between the source and target, contributing to significant variations.