scholarly journals Effect of reconstruction methods and x-ray tube current-time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study

2016 ◽  
Vol 43 (3) ◽  
pp. 1265-1274 ◽  
Author(s):  
J. D. Thompson ◽  
D. P. Chakraborty ◽  
K. Szczepura ◽  
A. K. Tootell ◽  
I. Vamvakas ◽  
...  
Keyword(s):  
Current Time ◽  
X Ray ◽  
Observer Study ◽  
Reconstruction Methods ◽  
Tube Current ◽  
Nodule Detection ◽  
Tube Current Time Product

The clinical significance of modifying X-ray tube current-time product based on prior image deviation index for digital radiography

2019 ◽  
Vol 63 ◽  
pp. 35-40 ◽  
Author(s):  
Takeshi Takaki ◽  
Toshioh Fujibuchi ◽  
Seiichi Murakami ◽  
Takatoshi Aoki ◽  
Masafumi Ohki
Keyword(s):  
Clinical Significance ◽  
Digital Radiography ◽  
Current Time ◽  
X Ray ◽  
Deviation Index ◽  
Tube Current ◽  
Tube Current Time Product

scholarly journals Benefits of Low-Dose CT Scan of Head for Patients With Intracranial Hemorrhage

Dose-Response ◽  
2020 ◽  
Vol 19 (1) ◽  
pp. 155932582090977
Author(s):  
Dan Wu ◽  
Gang Wang ◽  
Bingyang Bian ◽  
Zhuohang Liu ◽  
Dan Li
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Ct Scan ◽  
Low Dose ◽  
Ct Scans ◽  
Current Time ◽  
Low Dose Ct ◽  
Tube Current ◽  
Conventional Ct ◽  
Tube Current Time Product

Objectives: For patients with intracranial hemorrhage (ICH), routine follow-up computed tomography (CT) scans are typically required to monitor the progression of intracranial pathology. Remarkable levels of radiation exposure are accumulated during repeated CT scan. However, the effects and associated risks have still remained elusive. This study presented an effective approach to quantify organ-specific radiation dose of repeated CT scans of head for patients with ICH. We also indicated whether a low-dose CT scan may reduce radiation exposure and keep the image quality highly acceptable for diagnosis. Methods: Herein, 72 patients with a history of ICH were recruited. The patients were divided into 4 groups and underwent CT scan of head with different tube current–time products (250, 200, 150, and 100 mAs). Two experienced radiologists visually rated scores of quality of images according to objective image noise, sharpness, diagnostic acceptability, and artifacts due to physiological noise on the same workstation. Organ-/tissue-specific radiation doses were analyzed using Radimetrics. Results: In conventional CT scan group, signal to noise ratio (SNR) and contrast to noise ratio (CNR) of ICH images were significantly higher than those in normal brain structures. Reducing the tube current–time product may decrease the image quality. However, the predilection sites for ICH could be clearly identified. The SNR and CNR in the predilection sites for ICH were notably higher than other areas. The brain, eye lenses, and salivary glands received the highest radiation dose. Reducing tube current–time product from 250 to 100 mA can significantly reduce the radiation dose. Discussion: We demonstrated that low-dose CT scan of head can still provide reasonable images for diagnosing ICH. The radiation dose can be reduced to ∼45% of the conventional CT scan group.

scholarly journals MOBILE MICROFOCAL X-RAY DIAGNOSTIC COMPLEX IN THE IMAGING OF PREMATURE NEWBORNS

2021 ◽  
Author(s):  
Alexander Vladimirovich Alkhazishvili ◽  
Yuri Nikolaevich Potrakhov ◽  
Aleksandr Sergeevich Misyurin ◽  
Alexandr Valerievich Vodovatov ◽  
Aleksey Yur`evich Skripnik
Keyword(s):  
Radiation Risk ◽  
Research Centre ◽  
Risk Category ◽  
Current Time ◽  
Premature Newborns ◽  
X Ray ◽  
National Medical ◽  
Radiation Output ◽  
Tube Current ◽  
Diagnostic Complex

Aim. Estimation of the diagnostic capabilities of microfocal X-ray diagnostic complex for the imaging of premature newborns. Materials and methods. The study was performed on the base of Almazov National Medical Research Centre. The study included X-ray examinations of 156 premature newborns using the method of microfocus radiography: 139 X-ray images of the chest, 17 X-ray images of the abdomen. Imaging was performed using the projection magnification technique with the patient positioned close to the X-ray source. Results. The microfocal X-ray images had the necessary quality for the diagnosis of pathological changes in the chest and abdomen for babies. Patient dose estimation was based on the radiation output of the X-ray unit and tube current-time product. For the maximum values of tube voltage, tube current and exposure time effective doses did not exceed 0.02 mSv, corresponding to negligible radiation risk category. Conclusion. Microfocal radiography allows performing informative X-ray examinations of premature newborns, especially using the projection magnification technique. The use of microfocal X-ray diagnostic complex allows reducing patient doses, increasing the mobility and usability of the X-ray equipment. The first experience of clinical application of microfocal radiography in neonatology and pediatrics with projection magnification of the X-ray image was evaluated as successful.

Optimisation of CT scan parameters to increase the accuracy of gross tumour volume identification in brain radiotherapy

2020 ◽  
pp. 1-5
Author(s):  
Kosar Estak ◽  
Mohammad Mohammadzadeh ◽  
Nahideh Gharehaghaji ◽  
Tohid Mortezazadeh ◽  
Rahim Khatyal ◽  
...  
Keyword(s):  
Image Quality ◽  
Tumour Volume ◽  
Standard Protocol ◽  
Gross Tumour Volume ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Brain Radiotherapy ◽  
Tube Current ◽  
Tube Current Time Product

Abstract Aim: This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed. Materials and methods: A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method. Results: Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%). Findings: CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.

scholarly journals Sparse reconstruction methods in x-ray CT

2017 ◽  
Author(s):  
Juan Felipe Perez Juste Abascal ◽  
Monica Abella ◽  
Cyril Mory ◽  
Claudia de Molina ◽  
Nicolas Ducros ◽  
...  
Keyword(s):  
Sparse Reconstruction ◽  
X Ray ◽  
Reconstruction Methods

An Overview of 3D X-Ray Reconstruction Algorithms for PCB Inspection

2020 ◽  
Author(s):  
Alexandra Roberts ◽  
John True ◽  
Nathan T. Jessurun ◽  
Dr. Navid Asadizanjani
Keyword(s):  
Open Source ◽  
Printed Circuit Boards ◽  
Critical Role ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
Reconstruction Methods ◽  
Verification Methods ◽  
Pcb Manufacturing ◽  
Micro Tomography ◽  
The Government

Abstract Printed Circuit Boards (PCBs) play a critical role in everyday electronic systems, therefore the quality and assurance of the functionality for these systems is a topic of great interest to the government and industry. PCB manufacturing has been largely outsourced to cut manufacturing costs in comparison with the designing and testing of PCBs which still retains a large presence domestically. This offshoring of manufacturing has created a surge in the supply chain vulnerability for potential adversaries to garner access and attack a device via a malicious modification. Current hardware assurance and verification methods are based on electrical and optical tests. These tests are limited in the detection of malicious hardware modifications, otherwise known as Hardware Trojans. For PCB manufacturing there has been an increase in the use of automated X-ray inspection. These inspections can validate a PCB’s functionality during production. Such inspections mitigate process errors in real time but are unable to perform highresolution characterization on multi-layer fully assembled PCBs. In this paper, several X-ray reconstruction methods, ranging from proprietary to open-source, are compared. The high-fidelity, commercial NRecon software for SkyScan 2211 Multi-scale X-ray micro-Tomography system is compared to various methods from the ASTRA Toolbox. The latter is an open-source, transparent approach to reconstruction via analytical and iterative methods. The toolbox is based on C++ and MEX file functions with MATLAB and Python wrappers for analysis of PCB samples. In addition, the differences in required imaging parameters and the resultant artifacts generated by planar PCBs are compared to the imaging of cylindrical biological samples. Finally, recommendations are made for improving the ASTRA Toolbox reconstruction results and guidance is given on the appropriate scenarios for each algorithm in the context of hardware assurance for PCBs.

Effects of x-ray exposure on NOR and NAND flash memories during high-resolution 2D and 3D x-ray inspection

2016 ◽  
Vol 2016 (1) ◽  
pp. 000660-000665
Author(s):  
Anju Sharma ◽  
Preeth Sivakumar ◽  
Andrew Feigel ◽  
In Tae Bae ◽  
Lawrence P. Lehman ◽  
...  
Keyword(s):  
Exposure Time ◽  
Flash Memory ◽  
Low Energy ◽  
Memory Devices ◽  
Nand Flash ◽  
Flash Memories ◽  
Tube Voltage ◽  
X Ray ◽  
Data Corruption ◽  
Tube Current

Abstract In this paper, we present a detailed study on the effects of x-ray exposure on data corruption in commercially available NOR and NAND flash memory devices during x-ray inspection with a high-resolution Phoenix Nanomex system from GE. We investigated role of the x-ray tube voltage, tube current, device orientation, x-ray filters and photon energy. We explored the low exposure regime in detail when the first byte errors start occurring and also determined the absorbed dose for 100% byte errors. No data corruption was observed after the normal 2D x-ray inspection and CT scans of the NOR and NAND flash memory devices under study. However, increase in the tube voltage, tube current and/or the x-ray beam size resulted in byte errors which increased exponentially with the exposure time. The byte error rate was found to be much more sensitive to the tube voltage than the tube current. It was also affected by the device orientation with respect to the x-ray beam. The NAND flash memories were found to be more susceptible to data corruption from x-ray exposure than the NOR devices examined in this work. Some NOR devices were irradiated with the monochromatic x-rays from the CHESS synchrotron facility at Cornell University. Of all the photon energies used in this study, 12 keV x-ray irradiation resulted in the highest byte error rate. In this paper, we thus present a direct proof that it is the low-energy photon absorption that plays a major role in introducing bit errors in flash memories. Commonly available low-energy x-ray filters such as Cu and Al foils were found to be effective in preventing data corruption in such devices for long exposure time. Use of lower tube voltage, lower tube current, smaller x-ray spot size, short exposure time and low-energy x-ray filters, is recommended to prevent data corruption during 2D and 3D x-ray inspection of flash memory devices and other semiconductor devices in general.

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