Purpose: To evaluate the Monte Carlo code MCNP4B for low-energy brachytherapy calculations, including the effects of interseed attenuation and patient specific heterogeneities, on the calculated dose distribution from transperineal implantation of 125I.
Methods And Materials: The Monte Carlo code MCNP4B was used to model and benchmark the absolute dose distribution from two 125I brachytherapy seeds (model 6711 and 6702). Based upon the physical source model, the total photon intensity and differential energy spectrum were evaluated as a function of angle from the transverse bisector of the source. These spectral and intensity data were reformatted to produce probability distributions for sampling from a virtual point source. The virtual source model and a modified version of MCNP4B is then used for simulating arbitrary brachytherapy source configurations within a homogeneous or heterogeneous patient specific computed tomography (CT)-based lattice geometry.
Results And Conclusion: Comparison with TG-43 data and the Monte Carlo calculations is excellent with MCNP4B predicting the radial dose function for the 125I 6711 and 6702 sources within 6% for all data points tested. Attenuation effects from neighboring seeds were investigated for pre- and postimplant seed distributions and found to be negligible. Preliminary dosimetry analysis of postimplant seed distributions comparing homogeneous water versus heterogeneous CT simulation geometries indicates an average decrease of approximately 5.6% for the volume of tissue irradiated to a prescription isodose line of 144 Gy.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s0360-3016(99)00343-0 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Investigating time-independent and time-dependent diffusion phenomena using steady-state diffusion MRI.
Sci Rep
January 2025
Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
Diffusion MRI is a leading method to non-invasively characterise brain tissue microstructure across multiple domains and scales. Diffusion-weighted steady-state free precession (DW-SSFP) is an established imaging sequence for post-mortem MRI, addressing the challenging imaging environment of fixed tissue with short T and low diffusivities. However, a current limitation of DW-SSFP is signal interpretation: it is not clear what diffusion 'regime' the sequence probes and therefore its potential to characterise tissue microstructure.
View Article and Find Full Text PDFA Monte Carlo simulation and meta-analysis of health risk due to formaldehyde exposure at different seasons of the year in various indoor environments.
Sci Total Environ
January 2025
Department of Environmental Protection, Faculty of Geology, Geophysics, and Environmental Protection, AGH University of Krakow, Al. Mickiewicza 30, 30-059 Krakow, Poland.
Formaldehyde is considered as a significant contaminant. This study aimed to perform comprehensive research with systematic review, health risk estimation, meta-analysis, and Monte Carlo simulation to evaluate exposure to formaldehyde at different seasons of the year in various indoor environments. A systematic literature review was initially performed.
View Article and Find Full Text PDFTwo-dimensional Monte Carlo simulation coupled with multilinear regression modeling of source-specific health risks from groundwater.
J Hazard Mater
January 2025
University of Belgrade, Faculty of Technology and Metallurgy, Karnegijeva 4, Belgrade 11120, Serbia. Electronic address:
Effective protection of groundwater requires an accurate health risk assessment of contaminants; however, the diversity of pollution sources, variability, and uncertainties in exposure parameters present significant challenges in this assessment. In this study, groundwater risk estimates associated with NO, and F, along with fourteen heavy metal(loid)s (V, Cr, Mn, Fe, Ni, Cu, As, Co, Cd, Se, Pb, Hg, Zn, and Al) in an agricultural area were optimized by implementing positive matrix factorization (PMF), multilinear regression, and two-dimensional Monte Carlo simulations to characterize source-specific health risks. Groundwater pollution was analyzed considering regional variations, including differences in elevation, land use and land cover, and soil types.
View Article and Find Full Text PDFProbabilistic Approaches for Risk Assessment and Regulatory Criteria Development: Current Applications, Gaps, and Opportunities.
Integr Environ Assess Manag
January 2025
Institute of Environmental Toxicology, Western Washington University, Bellingham, Washington, USA.
Traditional ecological and human health risk assessment often relies on deterministic frameworks that preclude the presence of variability or uncertainty among input parameters characterizing exposure, effects, and risk. To promote increased realism and generate more robust risk management decisions, probabilistic risk assessment (PRA) has been introduced as a foundational grouping of techniques that seeks to broadly characterize variability among its components. While multiple methods exist (e.
View Article and Find Full Text PDFLife cycle of bioethanol production from blends of different food waste.
Environ Technol
February 2025
Technology Institute, University of Passo Fundo, Passo Fundo, RS, Brazil.
Food waste offers a potential source for bioethanol production, but productivity depends on the chemical composition of the raw materials and the processes involved. However, assessment of the environmental sustainability of these processes is often absent and can be carried out using the Life Cycle Assessment (LCA) methodology. This study aimed to perform an LCA on bioethanol production from mixtures of different wastes, including tubers, fruits, and processed foods, focusing on the gate-to-gate phase.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!