scholarly journals Results of the clinical evaluation of the low-dose protocols of the digital linear tomography of the chest

2020 ◽  
Vol 13 (1) ◽  
pp. 47-59
Author(s):  
I. G. Kamyshanskaya ◽  
V. M. Cheremisin ◽  
A. V. Vodovatov ◽  
A. N. Boriskina
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Early Treatment ◽  
Low Dose ◽  
Image Quality Assessment ◽  
Treatment Center ◽  
X Ray ◽  
Second Stage ◽  
Patient Doses

High levels of tuberculosis morbidity in the Russian Federation lead to the extensive use of X-ray diagnostics for the tuberculosis screening and assessment of the effectiveness of treatment. Digital radiography and computed tomography are traditionally used for the diagnostics of tuberculosis. These methods are associated with significant drawbacks: low specificity for radiography, high costs per examination, significant patient doses, and limited availability for computed tomography. As an additional method for the assessment of the effectiveness of the tuberculosis treatment it is possible to use linear tomography performed on the digital X-ray units. The aim of the current study was to evaluate the possibility of utilization of the digital linear tomography for the control of the effectiveness of tuberculosis treatment in a dedicated antitubercular medical facility. The study was divided in two stages. The first stage was aimed at the assessment of the diagnostic image quality of the digital linear tomograms obtained using the previously developed low-dose imaging protocols. Image quality assessment was performed using an anthropomorphic chest phantom and dedicated imitators of the lung lesions. Image quality was assessed by the experts (radiologists) based on the developed image quality criteria. Results of the first stage of the study indicate that all low-dose protocols allow obtaining images with at least acceptable image quality. Hence it was possible to propose low-dose protocols for clinical evaluations. The second stage of the study was performed as a prospective cohort survey aimed at the evaluation of the structure of X-ray examinations, patient doses and clinical image quality of the digital linear tomograms in antitubercular early treatment center. The cohort survey included two patient samples, uniform by age and gender composition, anthropometric characteristics and structure of diagnosis. One of the samples was imaged using standard (vendor) digital linear protocols, other – using the proposed low-dose protocols. Dose data collection (measurement of dose-area product and subsequent calculation of effective dose) and expert image quality assessment was performed for each patient. The results of the second stage of the study indicate that the use of the low-dose protocols allow reducing the patient effective doses per examination up to a factor of 6–8 (0.56 – 5.9 mSv for standard protocols; 0.2 – 1.15 mSv for low-dose protocols) due to the reduction in tube current-time product (126 mean mAs and 11 mean mAs, respectively). The dose reduction is accompanied by the reduction in the image quality of the linear tomograms (from “excellent” or “good” for standard protocols to “acceptable” for low-dose protocols). However, that dose not hinder the conclusion decision and identification of pathologies. Results of the study indicate that digital linear tomography can be used for the evaluation of the dynamics of the pathological process in the lungs with the previously defined localization of the pathology. The presented low-dose protocols were implemented into radiological practice of the antitubercular early treatment center. Currently, the proposed low-dose protocols are under evaluation for the large-scale study on the base of general practice hospitals

scholarly journals Improving Image Quality of Medical Low-Dose X-ray Image Sequences Using a Neural Filter

1999 ◽  
Vol 119 (11) ◽  
pp. 1383-1391
Author(s):  
Kenji Suzuki ◽  
Tatsuya Hayashi ◽  
Shigeyuki Ikeda ◽  
Isao Horiba ◽  
Noboru Sugie ◽  
...  
Keyword(s):  
Image Quality ◽  
Low Dose ◽  
Image Sequences ◽  
X Ray ◽  
Neural Filter

Typical errors when performing intraoral periapical x-rays, and their effect on image quality

2020 ◽  
pp. 36-44
Author(s):  
A.P. Arzhantsev
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Digital Image ◽  
Cone Beam ◽  
X Rays ◽  
Post Processing ◽  
X Ray ◽  
Selection Of ◽  
Periapical Radiography

During the study, intraoral periapical images were analyzed in 300 patients. The possibilities of using the methods of radiography and their influence on the quality of the obtained x-ray images were studied. The intraoral periapical radiography was compared with the results of orthopantomography and cone beam computed tomography. To identify the features of the mapping of zones of periapical destruction, 47 experimental x-ray studies were performed on skeletonized jaws with artificial defects in cortical plates. Often encountered errors are: an arbitrary choice of angles of inclination and the centration of the x-ray tube, the wrong location of the x-ray receiver in the patient's mouth, inaccurate installation or poor fixation of the patient's head, inefficient selection of physical and technical conditions of shooting, non-compliance with the conditions of the photo process with analog radiography or post-processing and printing digital image. The characteristic projection distortions of images resulting from these errors are analyzed and illustrated.

scholarly journals Possibilities of applying model-based iterative reconstructions in computed tomography of the lungs

2020 ◽  
Vol 24 (3) ◽  
pp. 107-113
Author(s):  
A. Yu. Silin ◽  
I. S. Gruzdev ◽  
G. V. Berkovich ◽  
A. E. Nikolaev ◽  
S. P. Morozov
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Low Dose ◽  
Ct Images ◽  
Lung Pathology ◽  
Diagnostic Quality ◽  
Screening Programs

Aim: A literature review of the possibilities of applying model iterative reconstruction (MIR) in computed tomography to improve image quality, including in low-dose scanning protocols.Materials and methods. The analysis of publications devoted to the application of MIR to reduce the radiation dose and improve the quality of images in CT diagnostics of lung pathology with an emphasis on the value of the achieved radiation dose was carried out.Results. The use of MIR eliminates digital noise from medical images, improving their quality. This feature can significantly reduce radiation exposure with low-dose protocols without loss of diagnostic quality. On average, application of MIR allows to reduce the radiation dose by 70% compared to a standard protocol, without increasing the noise level of CT images and maintaining the contrast-to-noise ratio. Previous studies have shown positive experience with the use of MIR in lung cancer screening programs and monitoring of cancer patients.Conclusion. The introduction of MIR in clinical practice can optimize the radiation exposure on the population without reducing the quality of CT images, however, the threshold dose to achieve a satisfactory image quality remains unexplored.

scholarly journals Temporomandibular joint imaging using cone-beam computed tomography

2020 ◽  
Author(s):  
◽  
Durer Iskanderani
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Cone Beam Computed Tomography ◽  
Low Dose ◽  
Cone Beam ◽  
Educational Tools ◽  
Radiographic Findings ◽  
X Ray ◽  
Absorbed Doses ◽  
Dose Optimisation

Cone-beam computed tomography (CBCT) is one of the most revolutionary innovations in dentistry, and was introduced into the dental field two decades ago as a three-dimensional (3D) imaging modality. Since then, it has gained general clinical acceptance, and is widespread among many dental specialties. The CBCT examination is a fast and user-friendly technique that provides multiplanar images with high spatial resolution, providing information that is unattainable with two-dimensional (2D) imaging in many diagnostic tasks. Thus, CBCT is an essential examination tool that can replace or complement other examinations. CBCT imaging plays a valuable role when hard tissue abnormalities are suspected in the temporomandibular joint (TMJ) by providing diagnostic information on cortical and subcortical boneintegrity or destruction/production changes. The growing availability and use of CBCT at dental clinics has led to concerns as to whether the information obtained by CBCT imaging justifies the additional exposure of the patient to radiation and the training required to examine and interpret the images. The radiation protection principles: justification and optimisation, should always be applied as the basis for protection. This thesis presents four studies on TMJ imaging using CBCT. In line with recent trends towards digital online education, two CBCT educational tools were developed for the interpretation of CBCT images of the TMJ and published on the Malmö University web site. The first was an educational tool including 35 CBCT examinations of TMJ, presented as 2D multiplane CBCT images. The second was a web-based programme containing 15 CBCT examinations of TMJ, presented as 3D multiplane CBCT images. Both tools included the image analysis criteria of the Diagnostic Criteria for Temporomandibular disorder (DC/TMD) as an assessment module, and were tested by dental students. It was found that they could be useful educational tools for TMJ assessment using CBCT images. The aim of the third study was to map and compare the distribution of absorbed doses using radiochromic film dosimeters in panoramic radiography and CBCT examinations of the TMJ using adult and child anthropomorphic head phantoms. Sheets of Gafchromic film (XR-QA2)were placed at five levels, corresponding to the radiographic examination, in the phantoms. The clinical protocols for panoramic and CBCT imaging of the TMJ of three dental X-ray units were used. The mean absorbed doses to a number of radiosensitive tissues within the oral and maxillofacial regions were estimated. The absorbed doses varied considerably among and within the radiosensitive tissues with examination type, X-ray unit, clinical setting, and patient age. The bonesurface and salivary glands received the highest absorbed doses in both radiographic examinations. The radiation burden was lower when using two small right and left fields of view (FOVs) than when using a single larger FOV. Accurate measurements of the absorbed dose in small dental radiation fields is challenging due to steep dose gradients. The use of Gafchromic film has shown promising results, allowing dose comparisons between different radiographic imaging. The last study was carried out to investigate the possibility of dose optimisation in CBCT examinations of the TMJ, in line with there commendations of the International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP). Thirty-four adult patients referred for CBCT imaging of the TMJ underwent two examinations with different scanning protocols, a manufacturer-recommended protocol (default), and a low-dose protocol in which the tube current was reduced to 20% of that in the default protocol. Three image stacks were reconstructed: the default protocol, the low-dose protocol, and the low-dose protocol processed using a noise reduction algorithm. Four radiologists evaluated the visibility of TMJ anatomic structures, image quality and radiographic findings. It was found that the visibility of the TMJ anatomical structures, the overall image quality and the radiographic findings using the low-dose protocol were comparable to those in the default protocol, indicating that diagnostically comparable results could be obtained with a five times lower radiation dose. Finally, this thesis highlights the diagnostics of TMJ imaging using CBCT in the context of image interpretation, imaging dosimetry and dose optimisation, all with the purpose of improving and optimising radiological TMJ diagnostics.

scholarly journals The Use of Artificial Intelligence in Computed Tomography Image Reconstruction: A Systematic Review

2020 ◽  
Vol 4 (2) ◽  
pp. 30-38
Author(s):  
Theresa Lee ◽  
◽  
Euclid Seeram ◽  
Keyword(s):  
Artificial Intelligence ◽  
Computed Tomography ◽  
Image Reconstruction ◽  
Image Quality ◽  
Low Dose ◽  
Ct Imaging ◽  
Clinical Implementation ◽  
Low Dose Ct ◽  
Dose Reductions

Background Current image reconstruction techniques in computed tomography (CT) such as filtered back-projection (FBP) and iterative reconstruction (IR) have limited use in low-dose CT imaging due to poor image quality and reconstruction times not fit for clinical implementation. Hence, with the increasing need for radiation dose reductions in CT, the use of artificial intelligence (AI) in image reconstruction has been an area of growing interest. Aim The aim of this review is to examine the use of AI in CT image reconstruction and its effectiveness in enabling further dose reductions through improvements in image quality of low-dose CT images. Method A review of the literature from 2016 to 2020 was conducted using the databases Scopus, Ovid MEDLINE, and PubMed. A subsequent search of several well-known journals was performed to obtain additional information. After careful assessment, articles were excluded if they were not obtainable from the databases or not available in English. Results This review found that deep learning-based algorithms demonstrate promising results in improving the image quality of low-dose images through noise suppression, artefact reduction, and structure preservation in addition to optimising IR methods. Conclusion In conclusion, with the two AI-based CT systems currently in clinical use showing favourable benefits, it is expected that AI algorithms will continue to proliferate and enable significant dose reductions in CT imaging.

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