scholarly journals Dosimetric Evaluation in Micro-CT Studies Used in Preclinical Molecular Imaging

2021 ◽  
Vol 11 (17) ◽  
pp. 7930
Author(s):  
Alexis N. Rueda ◽  
César Ruiz-Trejo ◽  
Eduardo López-Pineda ◽  
Mario E. Romero-Piña ◽  
Luis A. Medina

In microCT imaging, there is a close relationship between the dose of radiation absorbed by animals and the image quality, or spatial resolution. Although the radiation levels used in these systems are generally non-lethal, they can induce cellular or molecular alterations that affect the experimental results. Here, we describe a dosimetric characterization of the different image acquisition modalities used by the microCT unit of the Albira microPET/SPECT/CT scanner, which is a widely used multimodal imaging system in preclinical research. The imparted dose at the animal surface (IDS) was estimated based on Boone’s polynomial interpolation method and experimental measurements using an ionization chamber and thermoluminescent dosimeters. The results indicated that the imparted dose at surface level delivered to the mice was in the 30 to 300 mGy range. For any combination of current (0.2 or 0.4 mA) and voltage (35 or 45 kV), in the Standard, Good, and Best image acquisition modalities, the dose imparted at surface level in rodents was below its threshold of deterministic effects (250 mGy); however, the High Res modality was above that threshold.

2018 ◽  
Vol 10 (8) ◽  
pp. 2749
Author(s):  
Qi Wang ◽  
Fenzhen Su ◽  
Yu Zhang ◽  
Huiping Jiang ◽  
Fei Cheng

In addition to remote-sensing monitoring, reconstructing morphologic surface models through interpolation is an effective means to reflect the geomorphological evolution, especially for the lagoons of coral atolls, which are underwater. However, which interpolation method is optimal for lagoon geomorphological reconstruction and how to assess the morphological precision have been unclear. To address the aforementioned problems, this study proposed a morphological precision index system including the root mean square error (RMSE) of the elevation, the change rate of the local slope shape (CRLSS), and the change rate of the local slope aspect (CRLSA), and introduced the spatial appraisal and valuation approach of environment and ecosystems (SAVEE). In detail, ordinary kriging (OK), inverse distance weighting (IDW), radial basis function (RBF), and local polynomial interpolation (LPI) were used to reconstruct the lagoon surface models of a typical coral atoll in South China Sea and the morphological precision of them were assessed, respectively. The results are as follows: (i) OK, IDW, and RBF exhibit the best performance in terms of RMSE (0.3584 m), CRLSS (51.43%), and CRLSA (43.29%), respectively, while with insufficiently robust when considering all three aspects; (ii) IDW, LPI, and RBF are suitable for lagoon slopes, lagoon bottoms, and patch reefs, respectively; (iii) The geomorphic decomposition scale is an important factor that affects the precision of geomorphologic reconstructions; and, (iv) This system and evaluation approach can more comprehensively consider the differences in multiple precision indices.


2021 ◽  
Vol 119 ◽  
pp. 07002
Author(s):  
Youness Rtal ◽  
Abdelkader Hadjoudja

Graphics Processing Units (GPUs) are microprocessors attached to graphics cards, which are dedicated to the operation of displaying and manipulating graphics data. Currently, such graphics cards (GPUs) occupy all modern graphics cards. In a few years, these microprocessors have become potent tools for massively parallel computing. Such processors are practical instruments that serve in developing several fields like image processing, video and audio encoding and decoding, the resolution of a physical system with one or more unknowns. Their advantages: faster processing and consumption of less energy than the power of the central processing unit (CPU). In this paper, we will define and implement the Lagrange polynomial interpolation method on GPU and CPU to calculate the sodium density at different temperatures Ti using the NVIDIA CUDA C parallel programming model. It can increase computational performance by harnessing the power of the GPU. The objective of this study is to compare the performance of the implementation of the Lagrange interpolation method on CPU and GPU processors and to deduce the efficiency of the use of GPUs for parallel computing.


2001 ◽  
Vol 15 (1) ◽  
pp. 35-40
Author(s):  
Toshiaki Kodera ◽  
Toshihiko Kubota ◽  
Masanori Kabuto ◽  
Yuji Handa ◽  
Hisamasa Ishii ◽  
...  

2021 ◽  
pp. 1-17
Author(s):  
Roy Subhojit

The present work demonstrates an experience in estimating the threshold value of journey distances travelled by transit passengers using generalized polynomial function. The threshold value of journey distances may be defined as that distance beyond which passengers might no more be interested to travel by their reported mode. A knowledge on this threshold value is realized to be useful to limit the upper-most slab of transit fare, while preparing of a length-based fare matrix table. Theoretically, the threshold value can be obtained at that point on the cumulative frequency distribution (CFD) curve of journey distances at which the maximum rate of change of the slope of curve occurs. In this work, the CFD curve of the journey distance values is empirically modelled using Newton’s Polynomial Interpolation method, which helps to overcome various challenges usually encountered while an assumption of a theoretical probability distribution is considered a priori for the CFD.


Interpolation methods and curve fitting represent so huge problem that each individual interpolation is exceptional and requires specific solutions. PNC method is such a novel tool with its all pros and cons. The user has to decide which interpolation method is the best in a single situation. The choice is yours if you have any choice. Presented method is such a new possibility for curve fitting and interpolation when specific data (for example handwritten symbol or character) starts up with no rules for polynomial interpolation. This chapter consists of two generalizations: generalization of previous MHR method with various nodes combinations and generalization of linear interpolation with different (no basic) probability distribution functions and nodes combinations. This probabilistic view is novel approach a problem of modeling and interpolation. Computer vision and pattern recognition are interested in appropriate methods of shape representation and curve modeling.


2010 ◽  
Vol 39 ◽  
pp. 523-528
Author(s):  
Xin Hua Yang ◽  
Yuan Yuan Shang ◽  
Da Wei Xu ◽  
Hui Zhuo Niu

This paper introduces a design of a high-speed image acquisition system based on Avalon bus which is supported with SOPC technology. Some peripherals embedded in Avalon bus were customized and utilized in this system, such as imaging unit, decoding unit and storage unit, and these improved the speed of the whole imaging system. The data is compressed to three-fourths of the original by the decoding unit. A custom DMA is designed for moving the image data to the two caches of the SDRAM. This approach discards the method that FIFO must be put up in the traditional data acquisition system. And therefore, it reduced the CPU’s task for data moving. At the same time, the image acquisition and the data transmission can complete a parallel job. Finally, the design is worked on the high-speed image acquisition system which is made up of 2K*2K CMOS image sensor. And it improved the image acquisition speed by three ways: data encoding, custom DMA controller and the parallel processing.


Recent years have seen a marked increase in cardiovascular computed tomography (CT) imaging, with the technique now integrated into many imaging guidelines, including those published by NICE. Rapid clinical and technological progress has created a need for guidance on the practical aspects of CT image acquisition, analysis, and interpretation. The Oxford Specialist Handbook of Cardiovascular CT, now revised for the second edition by practising international experts with many years of hands-on experience, is designed to fulfil this need. The handbook is a practical guide on performing, analysing, and interpreting cardiovascular CT scans, covering all aspects from patient safety to optimal image acquisition to differential diagnoses of tricky images. The format is designed to be accessible and is laid out in easy to navigate sections. It is meant as a quick-reference guide, to live near the CT scanner, workstation, or on the office shelf.


Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2305 ◽  
Author(s):  
Zhongliang Wang ◽  
Hua Xiao

The huge volume of hyperspectral imagery demands enormous computational resources, storage memory, and bandwidth between the sensor and the ground stations. Compressed sensing theory has great potential to reduce the enormous cost of hyperspectral imagery by only collecting a few compressed measurements on the onboard imaging system. Inspired by distributed source coding, in this paper, a distributed compressed sensing framework of hyperspectral imagery is proposed. Similar to distributed compressed video sensing, spatial-spectral hyperspectral imagery is separated into key-band and compressed-sensing-band with different sampling rates during collecting data of proposed framework. However, unlike distributed compressed video sensing using side information for reconstruction, the widely used spectral unmixing method is employed for the recovery of hyperspectral imagery. First, endmembers are extracted from the compressed-sensing-band. Then, the endmembers of the key-band are predicted by interpolation method and abundance estimation is achieved by exploiting sparse penalty. Finally, the original hyperspectral imagery is recovered by linear mixing model. Extensive experimental results on multiple real hyperspectral datasets demonstrate that the proposed method can effectively recover the original data. The reconstruction peak signal-to-noise ratio of the proposed framework surpasses other state-of-the-art methods.


Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 148
Author(s):  
Xuefeng Chang ◽  
Kang Zheng ◽  
Dan Xie ◽  
Xiayun Shu ◽  
Keyu Xu ◽  
...  

An in situ image acquisition apparatus based on delay triggering for visualizing microdroplets formation is described. The imaging system includes a charge-coupled device camera, a motion control card, a driving circuit, a time delay triggering circuit, and a light source. By adjusting the varying trigger delay time which is synchronized with respect to the signal for jetting, the steady sequential images of the droplet flying in free space can be captured real-time by the system. Several image processing steps are taken to measure the diameters and coordinates of the droplets. Also, the jetting speeds can be calculated according to the delay time interval. For glycerin/water (60:40, mass ratio), under the given conditions of the self-made pneumatically diaphragm-driven drop-on-demand inkjet apparatus, the average of diameter and volume are measured as 266.8 μm and 9944 pL, respectively, and the maximum average velocity of the microdroplets is 0.689 m/s. Finally, the imaging system is applied to measure the volume of 200 microsolder balls generated from the inkjet apparatus. The average diameter is 87.96 μm, and the relative standard deviation is 0.83%. The results show good reproducibility. Unlike previous stroboscopic techniques, the present in situ imaging system which is absence of instantaneous high intensity light employs two control signals to stimulate the microdroplet generator and the charge-coupled device (CCD) camera. Hence, the system can avoid the desynchronization problem of signals which control the strobe light-emitting diode (LED) light source and the camera in previous equipment. This technology is a reliable and cost-effective approach for capturing and measuring microdroplets.


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