Background: Virtual wedge (VW) is used in radiotherapy to compensate for missing tissues and create a uniform dose distribution in tissues. According to TECDOC-1583 and technical reports series no. 430, evaluating the dose calculation accuracy is essential for the quality assurance of treatment planning systems (TPSs). In this study, the dose calculation accuracy of the collapsed cone superposition (CCS) algorithm in the postmastectomy radiotherapy of the chest wall for breast cancer was evaluated by comparing the calculated and measured dose in VW fields.
Methods: Two tangential fields with the typical VW angles were planned using ISOgray TPS in a thorax phantom. The CCS algorithm was used for dose calculation at 6 and 15 MV photon beams. The obtained dose distributions from EBT3 film spaces and TPS were evaluated using the gamma index.
Results: The measured and calculated dose values using VW in a heterogeneous medium with different beam energies were in a good agreement with each other (acceptance rate: 88.0%-93.4%). The calculated and measured data did not differ significantly with an increase/decrease in wedge angle. In addition, the results demonstrated that ISOgray overestimated and underestimated the dose of the soft tissue and lung in the planned volume, respectively.
Conclusions: According to the results of gamma index analysis, the calculated dose distribution using VW model with the CCS algorithm in a heterogeneous environment was within acceptable limits.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10445677 | PMC |
http://dx.doi.org/10.4103/jmss.jmss_7_22 | DOI Listing |
Vaccines (Basel)
December 2024
JSI Research & Training Institute, Inc., Arlington, VA 22202, USA.
A limited number of studies focus on estimating the costs of interventions to increase childhood immunization coverage in low- and middle-income countries (LMICs). Existing reviews often compare estimated costs but lack information on the methods used. The objective of this review is to summarize the methods used in costing studies that assessed interventions to reach zero-dose (ZD) children.
View Article and Find Full Text PDFVaccines (Basel)
December 2024
National Institutes for Food and Drug Control, No. 31, Huatuo Road, Beijing 102629, China.
Background: The Vero cell rabies vaccine is currently the most widely used human rabies vaccine. However, owing to the presence of residual host cell DNA (HCD) in the final product and the potential tumorigenicity of the DNA of high-passage Vero cells, the WHO not only sets a limit on the number of times cells used in production can be passaged, but also imposes strict requirements on the amount of residual HCD in the final vaccine product.
Objectives: To systematically reduce the HCD level in the final vaccine product, multiple purification steps are included in the vaccine production process.
Vaccines (Basel)
November 2024
Department of Data and Analytics, World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland.
Monitoring immunization inequalities is crucial for achieving equity in vaccine coverage. Summary measures of health inequality provide a single numerical expression of immunization inequality. However, the impact of different summary measures on conclusions about immunization inequalities has not been thoroughly studied.
View Article and Find Full Text PDFPharmaceutics
November 2024
Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
This study aimed to develop a quantitative analytical method for the simultaneous determination of cannabidiol (CBD) and melatonin (MT) in mouse plasma using the protein precipitation method coupled with LC-MS/MS. Additionally, this study sought to investigate the impact of CBD on the pharmacokinetics of MT in mice using this method. Mouse plasma samples were precipitated with acetonitrile and analyzed using a Kromasil 100-5-C8 (2.
View Article and Find Full Text PDFToxics
December 2024
Department of Toxicology, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Major Chronic Non-communicable Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Medical College of Soochow University, Suzhou 215123, China.
Acute and short-term toxicity tests are foundational to toxicology research. These tests offer preliminary insights into the fundamental toxicity characteristics of the chemicals under evaluation and provide essential data for chronic toxicity assessments. Fluoride is a common chemical in aquatic environments; however, the findings of toxicological data, such as LC for aquatic organisms, often exhibit inconsistency.
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