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Dosimetry - Crossref

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Last Updated: 03 August 2022

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CT dosimetry

The computed tomography medical examination is the single source of radiation to the general population in the developed world. Displayed dose measurements can be used with caution to calculate patient organ doses, safe dose, and risk, as well as a variety of models and applications. When interpreting dosimetry results, understanding of automatic exposure control and the effects of patient size is vital.

Source link: https://doi.org/10.1093/med/9780199655212.003.0015


A real-time optimal inverse planning for Gamma Knife radiosurgery by convex optimization: description of the system and first dosimetry data

OBJECTIVE The authors proposed a new, real-time interactive inverse planning system based on a fully convex framework, which would be used for Gamma Knife radiosurgery. METHODS is a website that provides an example of all potential shots' individual dose distributions of all potential bullets. The convex problem was solved, i. e. , which shots and at which weights would be used, considering that there is a shortage of funds to satisfy the needs while still minimizing the beam-on time. The device is called IntuitivePlan, and it helps data be moved from generated dose plans to Gamma Knife treatment planning software for further dosimetry analysis. CONCLUSIONS The possibility of using the Leksell Gamma Knife's advanced, real-time inverse planning in conjunction with the Leksell Gamma Knife opens new radiosurgery possibilities, particularly considering the possibility of using the full capabilities of the Leksell Gamma Knife's latest generations. This strategy gives new customers the opportunity of using the system for more and faster access to top-quality plans with a shorter technical education period and opens new planning opportunities for expert users. By doing so, intuitive graphical user interfaces can be created, allowing the user to directly connect with the planning system to graphically identify the desired dose map and to change on-the-fly the dose map by rotating, in a very user-friendly manner.

Source link: https://doi.org/10.3171/2018.7.gks181572


Gamma knife surgery for arteriovenous malformations in the brain: integration of time-resolved contrast-enhanced magnetic resonance angiography into dosimetry planning

Objects of this research The aim of this research was to develop an algorithm for the integration of time-based contrast-enhanced magnetic resonance angiography and dosimetry estimation for Gamma Knife surgery of arteriovenous malformations in the brain. Methods Twelve patients with brain AVMs referred to GKS underwent intraarterial digital subtraction angiography and time-resolved MR angiography, regardless of wearing an externally applied cranial stereotactic frame. Postprocessing with an interactive data language created hybrid data sets containing dynamic angiographic data and the MR markers that were essential for stereotactic transformation. In all 12 cases, stereotactic transformation of the mixed data sets containing the time-resolved MR angiography data with automatic detection of the MR markers was possible. In both cases, the stereotactic coordinates of vascular structures predefined from time-resolved MR angiography results were matched with DS angiography results. Conclusions Integration of time-resolved MR angiography results into the Leksell GammaPlan system for patients with brain AVMs is feasible.

Source link: https://doi.org/10.3171/jns-07/10/0854


A Mesh-Based Model of Liver Vasculature: Implications for Improved Radiation Dosimetry to Liver Parenchyma for Radiopharmaceuticals

Abstract Purpose: Background: Objectives: To allow a more precise differentiation of radiopharmaceutical decay sites within liver parenchyma than those within the organ's blood samples, the adult liver's internal vasculature model for blood dosimetry in radiation therapy. Through an in-house algorithm based on the ConstrainedConstructive-Optimization technique, individual lobe segments of the ICRP adult female and male livers were created within individual lobe segments of the ConstrainedConstructive-Optimization scheme. The liver capillaries and blood sinuses were among the AFL/AML's two regions: site specific liver models were developed and published in two regions, with specifically designed hepatic vessels in two regions; and site within the hepatic blood pool residing outside these vessels included the liver capillaries and blood sinuses. S-values for 22 radionuclides commonly used in radiopharmaceutical therapy were calculated using the updated dual-region liver models, which were then compared to S-values obtained in current dosimetric procedures: a single-region liver model of homogenized liver parenchyma and liver blood. According to respectively, S-values for alpha emitting radionuclides in the single-region AFL and AML models were approximately 14% and 11% higher than those calculated using the dual-region AFL and AML models, respectively. paraphrasedoutput:Conclusions: The liver's dosimetry of organ parenchyma was up to 13% and 11% higher than the single-region model for beta and auger-electron emitters, respectively.

Source link: https://doi.org/10.21203/rs.3.rs-1151866/v1


Biodistribution and Dosimetry Evaluation for A Novel Tau Tracer [18F]-S16 in Healthy Volunteers and Its Application in Assessment of Tau Pathology in Alzheimer’s Disease

Abstract Background : The aim of this report was to establish a fully automated radiosynthetic procedure for a novel tau tracer [18 F]-S16 and its performance, biodistribution, and dosimetry testing in healthy volunteers. Both [18 F]-FDG and [18 F]-FDG were also discussed, including the potential use of [18 F]-S16 PET imaging in AD tauopathies, as well as the identification of cerebral tau pathology and hypometablism patterns. The 18 F]-FDG PET imaging was used for AD diagnosis study in the study of suspected AD and healthy controls, as well as participants with a medical diagnosis of probable AD and healthy controls. We calculated mean activity in the pons as the reference region in the ten minute static results of [18 F]-FDG in ten min static data. Using the Mann-Whitney U test, AD and HCs were compared in different ROIs. Spearman rank correlation analysis was used to determine the voxel-wise correlations between [18 F]-FDG and [18 F]-FDG in AD patients with all cortical ROI regions. U00B1 60. 9 mg/MBq; The absorbtion dose of the urinary bladder wall was the highest, 133. 7 mm/bcSv/MBQ. In HCs, no definite [18 F]-S16 cerebral uptake region had been recognized visually. The SUVR of AD subjects in these regions was noticeably higher than that of HCs, with AD subject names much higher than that of HCs. In the substantia n. . . . and brainstem of both AD subjects and HCs, Tracer retention was observed. [18 F]-S16 PET indicated a high image quality for imaging tau deposition in AD patients and separating AD from HCs, as well as distinguishing AD from HCs.

Source link: https://doi.org/10.21203/rs.3.rs-958599/v1


Precision Dosimetry in Yttrium-90 Radioembolization through CT Imaging of Radiopaque Microspheres in a Rabbit Liver Model

Abstract Purpose: The aim of this paper is to perform precision dosimetry in a rabbit liver model using CT imaging of radiopaque microspheres, and to compare extracted dose measurements to those obtained from conventional PET-based dosimetry. Methods and Methods A CT calibration phantom was supposed to include posts with nominal microsphere concentrations of 0. 5 mg/mL, 5. 0 mg/mL, and 25. 0 mg/mL. The mean Hounsfield unit was extracted from the newspaper volume to create a calibration curve that compares Hounsfield units to microsphere concentrations. The application of the calibration curve to the CT liver volume was calculated by a CT-based activity distribution. Conclusions The calibration phantom reported a strong correlation with a slope of 14. 13 HU/mL, according to a linear least-squares fit to the average Hounsfield unit and microsphere concentration data, which in the calibration phantom showed a good correlation with a slope of 14. 13 HU/mL. The ANOVA analysis revealed statistically significant differences pf versus the mean dose derived from CT and PET, which showed no correlation between the mean dose obtained from CT and PET, but not PET.

Source link: https://doi.org/10.21203/rs.3.rs-806070/v1

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions