Purpose: 3D printing has become a popular and widely available technique of rapid prototyping. The impact of used materials on the dose distribution has been studied for high energy sources. However, brachytherapy sources emit lower energy photons, and materials used in 3D printing may differ. This study was conducted to analyze the influence of common materials (polylactic acid - PLA and acrylonitrile butadiene styrene - ABS) used in stereolithography.
Material And Methods: A 3D-printed phantom was designed, printed, and used to calibrate Gafchromic films. In the next step, a range of 1 mm thick plates of PLA and ABS (from zero to thirty) were inserted between source and detector to measure the impact of studied materials on delivered dose. Measurements were performed using a calibrated radiochromic film and Farmer ionization chamber in water.
Results: No statistically significant correlation ( = 0.4854) between the thickness of inserted PLA and the dose delivered to the film was obtained. With ionization chamber, Spearman's rank order test showed a significant correlation ( = 0.00004); however, the correlation was found weak. In case of ABS measurement, a statistically significant ( = 0.0159), yet weak negative correlation was found between the thickness of used material and the dose delivered to the film. On the other hand, a weak statistically significant ( = 0.0212) but positive correlation was found when the dose was measured with Farmer ionization chamber. We find these correlations false, as all measured doses were within the measurement uncertainty range (film ±8.0%, Farmer ±8.8%) from 100% of the prescribed dose.
Conclusions: According to obtained results, with the accuracy of measurement under clinical conditions, the impact of highly filled PLA and ABS printed objects on the dose distribution from an Ir source in water can be omitted.
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http://dx.doi.org/10.5114/jcb.2021.105287 | DOI Listing |
Phys Med Biol
January 2025
Radiotherapy and Radiation Dosimetry group, National Physical Laboratory, Hampton Road, Middlesex, Teddington, TW11 0LW, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Internationally, reference dosimetry for clinical proton beams largely follows the guidelines published by the International Atomic Energy Agency (IAEA TRS-398 Rev. 1, 2024). This approach yields a relative standard uncertainty of 1.
View Article and Find Full Text PDFAppl Radiat Isot
January 2025
National Institute of Metrology (NIM), Beijing, 100029, China.
A current measurement system named ICMS-TIA (Ionization Current Measurement System based on Transimpedance Amplifier) for rapid and accurate measurement of the ionization current of 4πγ ionization chamber is developed based on an improved high-value resistance I-V conversion method with range switching function. The effective measurement range of the ICMS-TIA is from 50 fA to 50 μA and the response time of the system is less than 2.8 s.
View Article and Find Full Text PDFInt J Part Ther
March 2025
Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany.
Purpose: The spot size of scanned particle beams is of crucial importance for the correct dose delivery and, therefore, plays a significant role in the quality assurance (QA) of pencil beam scanning ion beam therapy.
Materials And Methods: This study compares 5 detector types-radiochromic film, ionization chamber (IC) array, flat panel detector, multiwire chamber, and IC-for measuring the spot size of proton and carbon ion beams.
Results: Variations of up to 30% were found between detectors, underscoring the impact of detector choice on QA outcomes.
Tech Innov Patient Support Radiat Oncol
March 2025
Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan.
Purpose: This study aims to compare treatment plans created using RapidPlan and PlanIQ for twelve patients with prostate cancer, focusing on dose uniformity, dose reduction to organs at risk (OARs), plan complexity, and dose verification accuracy. The goal is to identify the tool that demonstrates superior performance in achieving uniform target dose distribution and reducing OAR dose, while ensuring accurate dose verification.
Methods: Dose uniformity in the planning target volume, excluding the rectum, and dose reduction in the OARs (the rectum and bladder) were assessed.
J Neurosci Methods
January 2025
Cognitive Neuroscience Laboratory, German Primate Center - Leibniz Institute for Primate Research, Goettingen, Germany; Faculty of Biology and Psychology, University of Goettingen, Goettingen 37077 Germany.
Background: Neuronal activity is modulated by behavior and cognitive processes. The combination of several neurotransmitter systems, acting directly or indirectly on specific populations of neurons, underlie such modulations. Most studies with non-human primates (NHPs) fail to capture this complexity, partly due to the lack of adequate methods for reliably and simultaneously measuring a broad spectrum of neurotransmitters while the animal engages in behavioral tasks.
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