In the radiotherapy treatment planning of a lesion located in the head region with small field radiation beams, the heterogeneity corrections play an important role. In this work, we investigated the influence of a bony heterogeneity on dose profile inside a soft tissue phantom containing a bony material. PDD curves were obtained by simulation using the Monte Carlo code EGSnrc and employing Eclipse(R) treatment planning system algorithms (Batho, Modified Batho, Equivalent TAR and Anisotropic Analytic Algorithm) for a 15 MV photon beam and field sizes of 2x2 and 10x10 cm(2). The Equivalent TAR method exhibited better agreement with Monte Carlo simulations for the 2x2 cm(2) field size. The magnitude of the effect on PDD due to the bony heterogeneity for 1x1, 2x2 and 10x10 cm(2) field sizes increases to 10, 5 and 3%, respectively.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0010466 | PLOS |
J Comp Eff Res
January 2025
Health Value, HE Department, C/Virgen de Aránzazu, 21, 28034, Madrid, Spain.
To estimate the cost-effectiveness of cetuximab in combination with radiotherapy compared with radiotherapy alone, for the treatment of locally advanced head and neck cancer patients in Spain. A probabilistic Markov model (second-order Monte Carlo simulation) with a five-year time horizon and quarterly Markov cycles was performed from the perspective of the Spanish National Health System (NHS). The additional cost and quality-adjusted life-year (QALY) gain per patient receiving radiotherapy in combination with cetuximab compared with radiotherapy alone was €4356 (95% CI: €4350-4362) and 0.
View Article and Find Full Text PDFIndian J Nucl Med
November 2024
Center for Research and Production of Radioisotopes, Dalat Nuclear Research Institute, Vietnam Atomic Energy Institute (VINATOM), Da Lat City, Lam Dong Province, Vietnam.
Aims: This study aimed to evaluate the principal technical characteristics of a well-type gas-filled ionization chamber dose calibrator used in measuring radiopharmaceutical activity, namely accuracy, repeatability, and linearity. Furthermore, this work also explored the correlation between the device's response and the position and volume of the radiopharmaceutical I-131.
Materials And Methods: Experimental measurements were conducted on the ATOMLAB 500 dose calibrator using NIST traceable Cs-137 source to determine the accuracy and repeatability.
Sci Rep
January 2025
College of Safety Science and Engineering, Liaoning Technical University, Fuxin, 123000, Liaoning, China.
The abandoned coal in goaf will adsorb the gases ethylene (CH) and acetylene (CH) produced by coal oxidation, which makes the concentration data of the indicator gas inaccurate. Therefore, the adsorption law of coal and CH and CH gas is explored. The macromolecular structure model of coal was established and optimized by simulation, and the gas adsorption process was simulated by means of grand canonical Monte Carlo method.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Chemical Engineering, IIT Gandhinagar, Gandhinagar, Gujarat 382055, India.
We compare the structures of polymer globules, composed of flexible polymer chains, with liquid droplets made of nonbonded monomers of the same polymer in poor solvents. This comparison is performed in three different poor solvents, with and without the addition of cosolvents. Molecular dynamics simulations are used to analyze the properties of the polymer globules, while semigrand canonical Monte Carlo simulations are used to form metastable liquid droplets of nonbonded monomers through homogeneous nucleation in the same solvents.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Radiation Oncology, Inha University Hospital, Incheon, Republic of Korea.
Background: High-dose-rate (HDR) brachytherapy using Iridium-192 as a radiation source is widely employed in cancer treatment to deliver concentrated radiation doses while minimizing normal tissue exposure. In this treatment, the precision with which the sealed radioisotope source is delivered significantly impacts clinical outcomes.
Purpose: This study aims to evaluate the feasibility of a new four-dimensional (4D) in vivo source tracking and treatment verification system for HDR brachytherapy using a patient-specific approach.
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